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Comment by seanhunter | Hacker News Reader

I worked with a guy who was crazy rich and wanted to build a great stereo. He went to a super high-end stereo shop and persuaded them to lend him a bunch of different speaker cables to "try out in his apartment". He was a phd engineer though, so rather than just listening to them he decided to do an experiment. He got some thick pure copper wire as a reference (got it from a hardware store because it's used to wire up domestic ovens and that kind of thing) and took his oscilloscope and measured the frequency response across all the cables. He found (as he expected) that the pure copper cable gave the best response so that's what he used to wire up his speakers. He did measure the acoustics in the room and put his speakers on metal pins on concrete blocks[1] to minimize mechanical interface between the speakers and the floor so the floor wouldn't clamp the bottom of the speakers.

His stereo sounded great and he was super smug about it, including taking the super expensive audiophile cables back and telling the shop they weren't as good as plain thick copper wire.

[1] This kind of thing https://images.homedepot-static.com/productImages/97a91edb-a...

View on HN

Here's a frequency response test pitting a coathanger against premium audio cable:

https://www.soundguys.com/cable-myths-reviving-the-coathange...

Spoiler: the difference between the coathanger and the premium cable is probably inaudible, and the difference between anything better than a coathanger (ie, literally any sort of copper wire) and the premium cable is certainly inaudible.

I had the same thought when I was building out my home theater system. Cables are cables, they're all just copper runs with gold plated ends, I'll just get whatever.

Well, I was dead wrong. Cheap cables hiss and hum like crazy when there's no signal.

Turns what you're paying for with expensive cables is better shielding around the copper. Unless you have perfectly air gapped cables that don't touch anything electrically conductive, they'll pick up some static charge and interference over a long enough run, and it's very audible.

So yeah, get half decent shielded cables for long unbalanced runs to passive speakers. Or just use balanced cables with active speakers.

The problem isn't that you cant make cables bad, its that you cant make cables excellent.

Its like vodka. There's certainly bad vodka, but there's not such thing as good vodka, only neutral tasteless vodka.

If we're using the vodka analogy. Vodka is the metal of the cable: the copper/aluminum/gold. Yes, you can have really bad quality metal, but it's practically unheard of given how easy it is to make good enough quality metal for cables.

What matters more is the rest of the ingredients mixed with vodka to make the cocktail (which is the connectors, insulation, and shielding of the cable). If those are good, they'll easily mask the common issues with cables. If those are bad, it doesn't matter how good your vodka/cable metal is.

just for the record, the shielding is metal or it's not shielding; it also needs to be grounded, but the power audio outputs of amplifiers are generally not designed for grounding; and you also need to worry about capacitance and inductance; twisted pairs might give you better noise characteristcs wrt AC wiring hum than shielding

I'm not saying wires don't matter and I'm not saying wires do matter, I'm saying inasmuch as they make a difference, there are plenty of ways to undermine what you are doing. Might be a better idea to send shielded high impedance signals around the room and put power amplifiers at the speakers.

Irrelevant to your point: some vodkas to my and many others' (generally Eastern European/Russian) tastes do taste good. I drink Stoli the same way I drink whiskey.

Hehe.

It is an example I ripped off of an old SV founder.

The Code of Federal Regulations upgraded Vodka in 2020.

Previously:

“Vodka” is neutral spirits so distilled, or so treated after distillation with charcoal or other materials, as to be without distinctive character, aroma, taste, or color.

Now:

Vodka: Neutral spirits which may be treated with up to two grams per liter of sugar and up to one gram per liter of citric acid. Products to be labeled as vodka may not be aged or stored in wood barrels at any time except when stored in paraffin-lined wood barrels and labeled as bottled in bond pursuant to § 5.88. Vodka treated and filtered with not less than one ounce of activated carbon or activated charcoal per 100 wine gallons of spirits may be labeled as “charcoal filtered.” Addition of any other flavoring or blending materials changes the classification to flavored vodka or to a distilled spirits specialty product, as appropriate. Vodka must be designated on the label as “neutral spirits,” “alcohol,” or “vodka”.

What does the sugar and acid do??? Does it cover up off flavors or something? Seems like that much would make it taste slightly like not vodka.

https://www.diffordsguide.com/g/1171/vodka/vodka-production-...

Thanks for the heads up.

They've ruined vodka and a great example.

>Turns what you're paying for with expensive cables is better shielding around the copper.

There's a threshold where any shielding improvement is inaudible, and that threshold is far below what most people would consider "expensive cables".

I'm surprised there's enough energy in the EMI to be audible unamplified! That would make it audible even if you just had the cable run and speaker with no hifi.

Shielding is definitely important on the "line" side and somewhat on the PSU side.

You make a good point about it being unamplified. To be fair, I pretty much committed every audio cable sin by running the cheap speaker cables in parallel with powered cables with the excess coiled up plopped on top of coiled power cables. Maybe it would've been fine just not running it parallel to power or not coiling.

But yes on very important for the line side. Connected a long cheap RCA cable to powered speakers, and the moment I pulled it across carpet the speakers started crackling. Then I understood exactly what my buddy meant by "these are garbage" when he gave them to me, so not too sure what the intended purpose of such a long poorly insulated RCA cable was.

> To be fair, I pretty much conducted every audio cable sin by running the cheap speaker cables in parallel with powered cables with the excess coiled up plopped on top of coiled power cables.

Ah yes, that is basically just an impromptu air-core transformer between mains and your speakers.

You could also get rid of the whole problem by using and entirely digital pathway right up to the speakers by means of AES3 or AES67.

I mean you could just snap some toroids on there too

Or use balanced cables

Speakers can't be driven with balanced cables.

Speaker cables are literally balanced, unless you're grounding them at the speaker. I grant you that if you're grounding them at the amp it's 'fake balanced', but if you're running an amp with an output transformer then it's literally balanced.

Also arguably you only need balanced when the noise gets way too much. When driving a speaker the power audio signal is much much much higher than any noise being picked up over a reasonable length.

For lengths longer than that, balanced cables (or digital signals over Ethernet) are used and the speaker has more local amplification.

Balanced gear is pro gear. Consumer audio is single ended.

I'm a little sad that they didn't link the obvious original inspiration for that test - this classic Audioholics forum post by Bob Dean from 2004: https://forums.audioholics.com/forums/threads/speakers-when-...

As far as I know, that post is where the coathanger wire test idea originated.

Another thing I really love about it when viewed in context is, right after he destroys the entire idea of expensive cables in one post, the immediate follow-up post is "Is your speaker system time coherent?" Some people will never be convinced.

The guy in the article could have saved a lot of money by learning what SINAD is before building a stereo that even looks noisy. I’m a little shocked when I see audio nerds who don’t know about audiosciencereview. Far too many people in the world are still buying line conditioners and fancy cables.

The part where they had a poll was very unscientific, it left comparisons to random audio equipment on the listeners end. Results would be based on the listeners situation more than the source.

Just some food for thought…

If you are doing long speaker cable runs and are using 12 gauge wire anyway… At some point it occurs to you, why not just use Romex ?

And, in fact, it’s a very good choice. 12/3 romex - typically used in three Way lighting circuits - gives you two speaker pair in one nice package.

Two downsides:

First, it can be confusing for future electricians, etc., who do not expect romex in the wall to be used for low voltage.

Second, stereo terminal connectors are not typically designed for solid copper and that can get a little frustrating and complicated.

… but then you think about it a little more and it occurs to you:

why not just build terminal blocks and make connections with WAGO lever nuts ?

Romex is grand at audio frequencies but what's even better is just sticking the amplifier in the speaker.

What you get from vanilla integrated speakers today is something that would have cost tens of thousands in the 90s and would not have been available in the 70s: dedicated amplifiers for each speaker element, with electronic crossovers and, if you want it, room correction.

If you stick the amplifier in the speaker, then you have much lower voltages and currents in the cable to the speaker, so you are, perversely, much more sensitive to noise that couples into your wiring.

As a silly and dramatic experiment, touch a wire connected to a passive speaker (without power applied — don’t zap yourself!). You won’t hear anything. Now touch the center pin of an RCA wire leading to a powered-on speaker with appreciable low frequency response, e.g. a subwoofer. Bzzzzzzzzz!

This is why balanced cables exist.

I really don't know why stereo components do not communicate digitally via ethernet cables. The only thing that won't work for is the output of the power amp.

My stereo is the usual rat's nest of various cables and connectors. I also have a tub full of various plugs, adapters, etc. Wouldn't it be nice to have a receiver that just had an ethernet connector on the back? Run it to an ethernet switch, and plug your turntable, TV, cassette player, into the switch?

One cool consequence is your components could be anywhere in the house, as any component could play over any powered speaker in the house.

> I really don't know why stereo components do not communicate digitally via ethernet cables.

If you’re building a new pro audio setup today, be it studio or even live sound, that’s likely how you’re doing it.

Even 20 years ago we had digital audio routers that worked pretty decently (not great, but well enough). This was a recording studio of course, not a home audio setting.

The reason we don’t have this in consumer audio is almost certainly cost. Now you need to add a ADC, Ethernet, and a small chip to run it all. Meanwhile nobody wants to run cables anymore and WiFi is everywhere. But of course putting WiFi in everything drives cost too.

The $10 Lightning to 3.5mm dongle for my iPhone has a microcontroller with RAM and an ADC, and the $20 lightning to Ethernet adapter has an Ethernet phy in it, so it's just a matter of someone getting funding, building it, and selling such a product. Latency would be a concern, but get a good firmware engineer on it.

It should be noted that the wifi version of this is sold by Sonos though I don't think they do surround sound for movie watching, but are focused on multi-room audio.

Sonos does surround audio with their sound bars, and you can connect them with Ethernet. There's also a hack to take the IKEA Sonos bookshelf speakers and connect them to different speakers, eg https://makezine.com/article/maker-news/hacking-the-sonos-ik...

I've used a couple of single/dual/tri-band wireless transmitters to hook up speakers, and I'd say I'm not really a fan. You have to be ok with dropped packets from interference (which happens pretty frequently if you're also sharing your 2.4/5/6ghz spectrum with WiFi), which is audible as silence or wrong sounds.

Or you're using a protocol that does retransmission/buffering, which introduces noticeable latency with the video or even between speakers.

WiFi is not so good as a replacement for wires — the latency is too high. The main contenders seem to be Dirac and AVB, both of which run over Ethernet. Dirac uses entirely ordinary Ethernet, and AVB wants some fancy extensions, which will bump up the price of your switches quite a bit.

For good audio, you want known, controlled latency, preferably with quite precise timing. For live audio, or for a fully convenient replacement for analog cable, you want that known latency to be very short.

And you either need no drops or you need an entire drop + retransmit cycle to fit within your latency. (Hmm, FEC could be used, I suppose — encode packets such that an entire lost packet could be recovered from the preceding packets plus the next couple packets.)

In the professional world, Dante seems to be taking over as the Audio over Ethernet solution.

I stream TV and music over the intertoobs all the time. It works fine. The bandwidth on a home network is much higher, so it should be fine.

There are wireless standards for this, no need for ethernet

https://www.wisatechnologies.com/speakers

I tried wireless speakers. They had poor fidelity and the music was often interrupted by static and dropouts.

The same thing happens with my Roku remote when I plug headphones into it.

No thanks.

Sonos works over WiFi just fine.

Doesn’t twisted pair solve this problem? You can encode signals in the difference in voltage between the two wires which means that any noise which occurs in both wires cancels out?

We have gotten pretty good at sending low voltage signals over wires with little to no noise so it seems like we can apply similar principles to audio gear?

Balanced signals are widely used in professional gear, and twisted pairs indeed reduce loop area, but it’s not perfect. I once helped out in a sound booth where the cables picked up AM radio, and some nonlinearity in the system made it audible.

> I once helped out in a sound booth where the cables picked up AM radio

This right here is part of the reason the "coathanger versus cable test" annoys me so much. All these wonderful graphs "proving" that cables don't matter never take environmental noise into account, which is frustrating because in reality that's exactly what you're testing.

The fact that you could pick up AM radio inside a sound studio means that, for experimental purposes, that environment is simply not good enough.

Are expensive cables mostly bullshit? sure. Do better cables still make a difference? My personal experience tells me absolutely yes, just usually not enough to matter to 95%+ of people.

Pro audio “snakes over cat5” seem to be thing now. Performers will probably connect their gear to the stage box using analog cables for the foreseeable future, but the big connection to the mixer seems likely to be digital in most new installations. (Just an analog snake cable, materials alone, may be more than the complete installed cost of a digital replacement.)

The mechanical design of pro audio balanced cables is poor and it's common to end up with a bad one in the field. A balanced amplifier with one input connected to a long unterminated wire is way worse than a single-ended cable would be under the same conditions. Even in consumer home use XLR cable ends will fail. We're stuck with it unfortunately unless you want full custom gear.

Genelecs and other pro-audio gear can get their signal via AES/EBU. Digital all the way through the chain up to the speaker is fantastic!

No I have a digital connection to the speaker, because I am modern and rational.

Meridian Audio have been making active digital speakers for over 25 years.

SPDIF input to every speaker with custom DSP to do digital crossover tuned to the cabinet and particular cones.

It's digital to the active speakers, and everything necessary happens there. I have a pair of genelec 8361a actives. They can become anything you want.

Assuming it's well designed. If so, this cant be beat.

Arent studio monitors this?

A lot of professional audio gear uses 5.08mm connectors. I bet WAGO makes some of them!

But be careful with NM-B cable. I didn’t find an exact reference in the NEC, but I bet that Article 200 and friends would not approve of the reuse of the bare conductor for anything other than ground and might also disapprove of using the white conductor for anything other than neutral. (If you’re not installing the cable in the wall, maybe it’s not subject to the NEC.)

Get some nice TC cable instead.

> using the white conductor for anything other than neutral.

Where the NEC applies, you can use the white conductor in a multiconductor cable for anything as long as it is "permanently reidentified", that is color coded where it is exposed. cf NEC 200.7.

I wonder if we're misunderstanding each other ...

I am not suggesting you dual-use your high voltage romex and also send audio signals on it ...

I am suggesting you run additional runs of romex dedicated solely to audio.

This would be NEC compliant.

Would it? You’re allowed to use chapter 3 wiring methods for audio, but two speaker circuits is four “ungrounded conductors.”

Red and black are fine for this purpose. I’m not so sure about white and bare.

Can you tape the ends red and black in this case? I thought there were some provisions for options there in case you had some super heavy cable but wrong color

The rules are different for <=4 AWG wires versus smaller wires. I don’t know why.

You can use tape or heat-shrink to re-identify a wire if its 4 AWG or greater or if it's part of a multiconductor cable (which NM-B is).

The reason for the 4 AWG rule is probably an economic one. Having spools of larger conductor cables in a variety of colors is not inexpensive. Allowing the reidentification seems reasonable, though I'd probably argue the cutoff could be thinner than 4. The multi-conductor cable exception is a practical [and economic] one. You might not be able to get multi-conductor cable assemblies with the exact color coding you need.

Ahh - makes sense - high amp cables get insanely expensive

I used 14ga (IIRC) security wire to wire all the ceiling speakers in my house back to the central amp.

It’s stranded copper with 2 conductors. Easy to run, fits in all the connectors, is cheap, and comes on big spools.

I seem to remember an article some years back that determined that CAT5 network cable made excellent speaker wire; though very thin, the wires were entirely capable of carrying the electrical signal, and the twists prevented interference from nearby electrical fields.

Speaker wire? Are you sure? Network cable has it all wrong for speaker cable.

Speakers are typically around 4-8 ohm. With long cables, it is easy to get several ohms of resistance, meaning a significant part of the current is going to end up heating the cable instead of producing sound. Not only it is a waste, but impedance is frequency-dependent, so sound quality will be affected. It is not audiophile bullshit, you can hear it clearly. What you need are the thickest and shortest cables that you can reasonable use. For very long distances, active speakers are preferable, or a high voltage (typically 100V) line and transformers.

Interference doesn't matter. You are putting lots of power in these wires, enough to move the speaker membranes, then move the air, then move your eardrums. Compared to that, what you get from external sources is negligible. If you hear humming, that's a ground loop, and your speaker wires are not at fault.

Now CAT5 cable could make great subwoofer cables. I don't know, but it kind of makes sense. Subwoofer cables are low current, and therefore more likely to pickup parasites. They also tend to be longer than typical interconnects. So shielding and twisting may help.

The resistance of copper cable is often overstated. Quality network cable has about 0.1 ohm/m/direction. So two pairs in paralel for each direction (4 wires), for a total of 5m should have about 0.25 ohm total resistance. I wouldn't say audiophile approved, but probably very close to undetectable for most, both regarding the loss and the response.

> but probably very close to undetectable for most, both regarding the loss and the response.

Yah. Take an 8 ohm speaker, which might vary from 5 to 20 ohms, but is relatively close to 8 ohms for much of its range.

At 5 ohms, your voltage is attenuated by 5% -- this is -0.45dB. Re: the "heating the cable" waste, you're losing .45 dB of sound output to heat.

At 20 ohms, your voltage is attenuated by almost nothing (.05 dB).

In any room, and with any real driver and amplifier you're going to have far bigger concerns for flatness of response than this .4 dB variation.

Bigger concerns are--- having something stranded and chonkier with big thick insulation is good for robustness and strain relief instead of trying to abuse network cables (even stranded) for the job. You can get thicker, nicer wire for this purpose than network cable for less money.

Not for speaker wire I wouldn't think, but it can carry balanced audio very well - people make converters to XLR or jacks that carry four balanced signals over a single CAT6 cable (using the shield also for ground). Given it's pretty close to the right impedance it can carry microphone or line level balanced audio very well.

It's a bit humorous to think audiophiles might be spending thousands of dollars on speaker cables to listen stuff that could have passed through literally $5 cables in the studio.

Just use balanced audio.

Passive speakers are naturally balanced, the necessary conditions being (a) stray currents induced in the cable see the same impedance on both wires, therefore producing identical voltage deviations (common-mode noise), and (b) the sound produced by the speaker is a function of the voltage difference between the two wires.

If induced noise is a problem in such a setup, the actual improvement to be made would be to use twisted pair or shielded cable, rather than bare parallel wires. This helps eliminate differential-mode noise due to near-field EMI which parallel wires are susceptible to.

do non active speakers support balanced audio? I mean

Interference isn't a problem in speaker cables because it is an amplified signal, so any added noise is too little to be audible.

> Interference isn't a problem in speaker cables because it is an amplified signal, so any added noise is too little to be audible.

I dispute that. Source: I could hear at a previous apartment where I used to live that something was off when I was listening to music. It was subtle, but it was there. It drove me mad until I realized that by lifting the speakers cable off the floor the interference was gone.

I don't care about the science in this case. I just don't for I've witnessed it myself (well, heard it really). I've tested my theory (lifting the cable of the ground) and repeated the experiment. It is a fact (for you it may just be a comment on the Internet, but for me it is factual).

Putting the cables on little wooden pieces I made got rid of the interference (at least I couldn't hear it anymore).

That was happening on a "budget" (less than $1 K) setup (including a DAC). Very clean source: bitperfect rips of my CD collection.

Quiet room. The added noise was noticeable and was perturbing the listening.

If there was interference then you would _always_ hear it, not just when playing music. In fact, it would be significantly easier to hear it when not playing music.

Yes, it's annoying and only very noticeable when the speakers were supposed to be silent, but weren't and hissed and hummed instead.

Swapped for better shielded cables and the hiss/hum went away and it was dead silent when it was supposed to be.

But it was also only noticeable on the satellite speakers that had 50ft+ cable runs. It was inaudible on those short <6ft runs.

Can you please link the cables you purchased?

Weird things can happen. If you pick up RF on the speaker wire, it can make the output stage of the amplifier nonlinear in weird ways.

The extreme case is when you can receive radio signals on the speaker wire that are rectified and amplified by the amplifier; but you can get wonkiness short of that.

This is not an issue for anyone.

https://www.youtube.com/watch?v=gL4O_Do2PuQ

I've fought these arcane issues before. I don't have a ton of experience in audio, but I've seen them at lower frequencies (in servo amplifiers, where rectified RF causes DC offsets) and higher frequencies (as intermodulation in RF amplifiers from strong out-of-band interfering signals).

This is why you find things like this in design manuals. These are focused on offset errors in instrumentation amplifiers hooked to long cables (but intermodulation is an equal or larger concern in applications that care about frequencies above DC):

"In addition to filtering the input and power pins, amplifier outputs also need to be protected from EMI/RFI, especially if they must drive long lengths of cable, which act as antennas. RF signals received on an output line can couple back into the amplifier input where it is rectified, and appears again on the output as an offset shift."

https://www.analog.com/media/en/training-seminars/tutorials/...

Microchip says the same thing: "Amplifier outputs also need to be protected from EMI/RFI, especially if they must drive long lengths of cable, which act as antennas. RF signals received on an output line couple back into the amplifier input where they are rectified and appear again on the output as an offset shift."

https://ww1.microchip.com/downloads/en/appnotes/00001767a.pd...

https://www.physicsforums.com/threads/how-does-an-amplifier-... post #4

Note that I'm not really saying you need anything special on speaker cables, other than common sense: don't separate the pair for as much of the run as possible, and make sure the terminations at the end are not total garbage. If you have strong RF sources nearby, like when I had a 50W HF transmitter in my apartment, you may need to add RF chokes/ferrites on the amplifier end of speaker cables to reduce interference (I did).

Indeed, the ARRL (American Radio Relay League, an amateur radio association) describes that adjusting speaker cables is a frequent way to cure interference for neighbors of people with high power transmitters:

"Speaker wires are often 8 to 16 feet long. When you put two of them together, you make an efficient receiving antenna. Try bundling the speaker wires to reduce their effectiveness as an antenna. This procedure has been known to eliminate the interference all by itself."

"A: For a detailed explanation, you can refer to the ARRL Handbook's section on controlling RFI, and the section of the ARRL web site on EMI/RFI Products and Other Resources. You can build two of them, one for each speaker output. Wrap ten to fifteen turns of speaker wire onto an FT-140-43 ferrite core. Use an FT-240-43 if the speaker wires are large, and use "73" material for interference from 80 or 160-meter signals. Alternately, type "31" material is an excellent general purpose choice for HF. Install them right at the amplifier. If the system uses amplified speakers, you should install one at each speaker, too."

https://www.arrl.org/audio-1

This is all covered in the video I linked. Your whole post is classic HN. Waste everyone's time with irrelevant information. There is a reason it's not easy to find shielded speaker cables. It's not needed.

Dude, if people fix RFI problems by shielding speaker wires and putting ferrites close to the amplifier on speaker wires, clearly speaker wires are antennas for RFI that can affect amplifier performance.

Asking me to figure out what you're arguing based on a 17 minute video is not reasonable. I skimmed the video and took my best guess of what you're advocating. (It's not a representative or useful test; yes, it's harder to measure RF on a cable when it's plugged into an amplifier, but that doesn't tell you that RF on cables can't be rectified and amplified by the amplifier). You can use your words yourself.

In any case, the people who have asserted that RFI can get into ampifiers from speaker wires and cause problems are correct.

Your assertion "this is not an issue for anyone" contradicts the direct experience of lots and lots of people who have lived close to large RF sources and had RFI problems in audio fixed by adjusting speaker wires, such that it's the first step for engineers and radio amateurs working with angry neighbors.

It’s quite simple. I am asserting that interference on speaker wire running from an amplifier to a passive speaker doesn’t matter. Saying otherwise was invented by snake oil peddlers and you are doing harm with your akshually act.

RFI on a speaker wire going back to the amplifier is a big problem. As evidenced by all those sources.

Buying more expensive cables isn't generally the cure and is snake oil. Indeed, shielding itself can add enough capacitive loading to actually reduce speaker high frequency response.

But having to put in an RF choke on speaker wire to prevent RFI from having negative audible effects is common. And using a little bit of care to keep as much of the cables paired as possible, keeping runs as short as reasonably possible, and making reasonably good terminations is good insurance against it being a problem for you.

I've given plenty of high quality evidence, while you've given a long video of someone making a measurement that is meaningless to what I'm asserting.

You have provided no evidence someone can walk into a store and buy an amp, speakers, and speaker wire and suffer any problems due to RF interference.

> You have provided no evidence someone can walk into a store and buy an amp, speakers, and speaker wire and suffer any problems due to RF interference.

The ARRL wouldn't have to help neighbors of amateurs put chokes on speaker wires if this couldn't happen.

Most of us have the experience of having a cellphone close to speaker wiring and hearing LOUD buzzes and clicks. It was a bigger problem in the AMPS days (with higher output power), and more often the interference gets into the amplifier by signal lines than it does by getting in through power lines and speaker wires, but it can certainly go in the output (or power) as well. Have you never experienced this?

I still remember the first time I experienced this. I was 12, returning from a road trip with my (older) sister and her significant other's family, where we had handheld CBs. The hifi inside the house was demodulating and amplifying our CB signals; they could be clearly heard when we used the CB from the driveway. 5 meters of speaker cable was a good antenna for a 10 meter wavelength RF signal; a poorly filtered amplifier stage was demodulating and amplifying the signal.

Your Grandpa stories are completely irrelevant to this thread.

Interference will not generate significant current in the cables, but for a sufficiently long run, it can generate measurable voltages at your amplifier output. Depending on the power stage, this can cause your amplifier to react to the interference (e.g. if there is high-impedance negative feedback). With just the correct setup, a poorly designed power stage, and a long enough speaker cable run, you can pull in an AM station.

If you have a reference showing audible noise resulting from interference on a speaker cable running from an amplifier to a passive speaker then please share it.

This happens near loads of broadcast AM stations.

https://www.reddit.com/r/audio/comments/rfmfkq/home_audio_sp...

Everyone in that thread says it's not the cables.

> any added noise is too little to be audible

One would think so...

Class-D amplifiers pump out a signal literally buried in noise. You can't hear it because it's all shifted beyond human hearing and filtered by the speakers.

Class-D amplifiers are basically PWM run through some capacitors as a low-pass filter. The speakers are not what do the filtering, it's the capacitors.

https://youtu.be/TVCmPrDthlE

Whether it's "too little to be audible" depends on how sensitive your speaker driver is and what the noise floor of the room is.

In the video I linked, he was unable to induce any noise into the speaker wires greater than -130db at 60hz. The threshold for human hearing in absolutely ideal circumstances is about -115db. Anything less than that is provably inaudible for all frequencies, and for 60hz the threshold is much higher than -115db. The noise floor of the room only raises that further. For perspective, the very best state of the art DACs can only keep noise levels to -123db and just a few years ago the number was significantly worse.

The design of an amplifier stage often looks like this:

https://toshiba.semicon-storage.com/us/semiconductor/knowled...

Where the triangle isn't perfectly linear. If any RF gets into the output, it can be converted to audio frequencies by the nonlinearity and amplified. The open loop gain of the amplifier component can increase the magnitude of signals like this by tens of decibels.

If noise gets into the pre-amplified signal then it won't matter which wire you use to connect the speakers. This is why ground loops are bad.

> If noise gets into the pre-amplified signal

Nah-- it's about high frequency noise getting in via the speaker lead, and coupling to the negative feedback of the amplifier stage, and getting rectified and amplified.

Yes, most interference is via line level inputs, but it can easily be via the "output" as well.

And yet in real consumer hardware this is never an issue. Do you just like wasting people’s time?

I have a sneaking suspicion they already knew that!

The shops know this. High-end hifi is full of grift. It literally relies on people with more money than sense who can be persuaded to spend a fortune on components and extras that either make no difference to the sound or make it objectively less accurate.

Which is why you get nonsense like directional cables, cable supports to keep cables off the floor, cables with magic insulation, magic rocks that go on top of components, magic knobs, magic creams, "quantum" anything, grounding boxes full of pebbles that don't ground anything, and so on.

Also, most of the people who can afford this hobby are rich old boomers who often can't hear much above 7k on a good day.

I had a friend in college who worked part-time at a shop that sold and installed audiophile gear. He was a music engineering major, so he was aware of how much of what they sold was snake oil. Example: a 3-foot RCA cable that sold for several thousand dollars. The jacks were gold-plated. Not just with ordinary gold, but "special" gold. From a particular mine in South Africa. He told me once "If I ever sell that cable, I don't know how I'll live with myself."

One time he and another guy had just completed an installation in a very wealthy customer's home. Hundreds of thousands of dollars on an ultra-high-end amplifier, CD player, speakers, etc. He started playing one of the customer's CDs on the systems. The customer went on and on, lavishing praise at how "warm" and "crisp" his music sounded on the new system. Suddenly my friend's co-worker leaned over and whispered, "Do you hear that?..." My friend knew exactly what he was referring to: they had accidently wired the speakers out of phase.

My favourite variant of this is high-end digital audio cables.[1] Presumably the ones are really spiky and the zeros are really round when you use such a cable.

[1] yes this really does actually exist as a thing.

If USB-C has taught me anything it’s that higher signal integrity in more expensive cables is actually really a thing. I have usb-c devices which are so temperamental (razer kiyo pro) that they won’t run stable without actual thunderbolt cables. Even high-end fasgear 10gbps/100w cables aren’t good enough signal integrity or the camera will eventually freeze and crash. The extra thunderbolt shielding/better termination really does make a difference even if the pairs are not being used.

Hdmi and DP cables also have a range of shielding and termination quality, and pushing more data through them will show the difference, especially in longer lengths that are at the limit of the spec. Everything looks good when you are only doing 1080p30, try doing 2160p120 on a tv or UWQHD 160 hz on a pc, with a max-length (2m) cable and tell me every cable is just as good. Even every DisplayPort 1.4 cable or hdmi 2.1 cable is not “as good” let alone a rando lower-tier cable with the older shielding.

Oculink folks know damn well that not every cable is just as good either. Copper oculink cables are a fucking mess.

I’m not saying Monster wasn’t ripping you off for some gold-plated connectors, especially back in 2000 when hdmi stated with 1.x in the name. But the reality is that if nothing else we have manifested the world where digital cable quality matters. And really the “hurr durr digital signals” thing has always been a little bit of an oversimplification, even as someone who’s said it before too.

There isn’t a correlation with price in the high end, going from a $30 cable to a $150 cable doesn’t get you anything, but going from a $5 cable to a $30 cable you certainly do get better shielded cable and better termination if nothing else, and yes, it does make a difference when you are actually pushing the spec to the limit. You will definitely find out that not even all 10gbps usb-c or hdmi 2.1 UHBR cables are created equal let alone ye olde hdmi 1.3 bullshit cable.

Two points:

Digital audio, no matter how high quality and how many channels, uses vastly less bandwidth than even the lowest quality video signal these days. At absolute best, lossless audio with 16 channels is still less total bandwidth than even USB2.0 speeds. It’s just not fast.

Although signal integrity matters, signal integrity in digital signals is almost always not silent degradation. And often is extremely obvious degradation. So if your cable has problems, you know almost immediately (or, when it happens you know). Unlike analog audio, it either works or it doesn’t. In the marginal case you don’t just get worse sounding audio… you just don’t have audio periodically which sounds super obvious to the ear.

Just to support your point, there are many professional digital audio products used for recording that quite literally run on USB 2.0. For instance, this well respected interface that supports 32 channels in and out up to 192khz: https://www.sweetwater.com/store/detail/DigifaceUSB--rme-dig...

RME is a special case. They use an FPGA in the interface and own protocol to realise 70! input/output channels and sub Firewire latencies over USB2.

https://www.rme-audio.de/rme-usb-technology.html

You're about an order of magnitude wrong. USB2 can transport close to 200 channels at studio quality (24bit 96 Khz).

Why so aggressive? I didn’t make any claims other than less than USB2.

And for reference, I was assuming 384 kHz, 32 bit depth, which would be 196 Mbps at 16 channels. You cannot even do 32 channels over USB2 which would be the next logical step.

Sorry you got offended, that wasn't my intention. Pointing out inaccuracies is not aggressive, and in this case, I was reinforcing your claim, by saying USB2 is not only capable of tens of audio channels, but hundreds.

I was just adding context, and I'm happy you provided even more. 32/384 is indeed at the extreme top of digital audio signals, beyond what many people consider to be useful. Even in such cases, USB2 can still do the job, but most modern devices will use USB3 or Thunderbolt, simply to avoid issues and ensure enough headroom on the digital bus.

384 kHz, 32 bit depth

This is nonsense for recording or playback. Maybe someone works with this internally but there is no reason to output this over usb.

> there is no reason to output this over usb

some inexpensive SDR dongles sidestep the question of getting a really good high-bandwidth ADC (still not cheap even today!) by just hooking up an intermediate frequency stage which downmixes RF to AF, and then you just hook it to one of the innumerable sound cards on the market to pull it into the PC for processing etc.

Wider bandwidth is wider bandwidth, the faster your sample rate the wider the range that you can sample. Iirc it's nyquist rate, so, with 384kbps rate you can sample a 192khz window.

Are you really taking a discussion about audio and making some sort of niche invented case of making a sound card be the analog to digital conversion from a software defined radio?

Even in that case 32 bit sampling is nonsense, the resolution of detecting voltages is never going to be accurate enough to need 4 billion different levels.

I'm actually quite serious, of the people who are buying really hi-fi audio inputs, it's not unlikely a large number of them are quite interested in the actual bandwidth of the input. They're using that sampling headroom for something else (oversampling).

Regulation and stabilization is a whole ""niche"" area of electronics called "voltage regulation" and yes, you can improve it a lot (and you can only do your best regardless of instability of the base). Actually a lot of audio engineers would be feeding it clean (linear regulated) power in this case as well. My Astron linear supplies are quite clean for radio and would be excellent for audio too.

https://www.eham.net/reviews/view-product?id=1616

https://www.eham.net/reviews/view-product?id=9570

USB optoisolator + linear regulated supply on a hub on the other side is something I've seriously considered for a nice SDR setup even short of that.

Again, of the people who buy this stuff, yes you will find a lot of people paying attention to the details and buying/building esoteric setups. Hams exist and the hobby almost inherently involves opening up the checkbook lol. Even decent audio gear is generally going to be $500-1000 most of the time.

While I agree with you, you can find 384 kHz 32-bit playback available on many of their LG cell phones as a marketing feature. Does it matter? No. Does it exist, even in consumer electronics? Yes.

High speed digital signaling over differential pairs requires precise impedance control to handle multi-gigahertz data rates. You're paying for that in a high quality USB3 cable. Audio signals running below 20 kHz are in a completely different electrical regime that doesn't require special manufacturing attention. It's easily doable with 19th century technology.

Right, but in the context of an audio stream, it's not going to matter these days.

Even a hugely overkill uncompressed 8-channel, 32 bit, 192kHz sample rate audio stream[1] is under 50 megabits/second.

Any digital cable and transceiver from USB 2 (480Mbps) or 100BASE-T Ethernet (100Mbps) onwards will handily do that, with headroom for so much forward error correction that you probably won't expect a single bit error in your lifetime.

[1]: good luck getting a clock with low enough sample aperture jitter to actually record that in the first place, it's probably under a femtosecond.

it's probably under a femtosecond.

What are you talking about here? A femtosecond is a quadrillionth of a second. 10gbs would mean one 10 billionth of a second.

If the sample clock edges aren't very (very very very) regular, on a sample-and-hold ADC, the waveform isn't sampled evenly and that manifests as noise that swamps the detail provided by the higher bit depth.

This is called "sample aperture jitter". Requirements scale linearly with frequency and exponentially with bit depth.

These a calculator here:

https://www.analog.com/en/design-center/interactive-design-t...

https://www.analog.com/en/technical-articles/aperture-jitter...

Sure enough, 32 bits sampling a 96kHz signal, which is the Nyquist frequency of 192kHz sampling rate, is 0.3fs. At 24 bits, it's more like 100fs, which is much more doable, but still not easy. Which is why audio bit depths usually don't go to 32 bits, despite formats like FLAC supporting that.

The practical upshot of this and other noise sources is that higher audiophile-grade bit depths and sampling frequencies are quite likely to have at least some of those bits swamped out by noise on real hardware.

This is just getting the audio recorded. Playing it back as physical sound waves adds something between quite a bit and radically more noise to the signal, even if there's never any lossy compression.

It seems like you are arguing with someone that 32 bits per sample is too much resolution and I agree, but I'm not sure who you are are arguing with or who is saying that.

It was an interesting (to me) footnote to the point that even if you massively overspec your audio stream to the point of physically being unable to record the audio at that quality (the footnote being why it's unfeasible), you can still easily fit many such streams down a single modern-ish digital link.

The point isn't that you shouldn't record audio at 32-bit depth (which you probably shouldn't if you expect it to bring much benefit, but that's by-the-by), it's that even if you did, and you have a 7.1 system with 8 uncompressed streams, you still won't be anywhere near the point where USB 3 cable grades will start to matter.

You're the one who asked for clarification on the footnote specifically.

>UWQHD

I agree, sending Alphabet Soup down those cables isn't going to end well. Those things aren't designed to carry liquids.

> I have usb-c devices which are so temperamental (razer kiyo pro) that they won’t run stable without actual thunderbolt cables.

That is a device problem, not a "there is a need for better cables" problem.

This is why you have to be careful to avoid 90 degree bends in high end wire like this so the ones don’t get jammed up and stop the flow of sound.

Nothing will top the $485 wooden volume knob:

> Dynamics are better and overall naturalness is improved. Here is a test for all you Silver Rock owners. Try removing the bakelite knobs and listen. You will be shocked by this! The signature knobs will have an even greater effect…really amazing! The point here is the micro vibrations created by the volume pots and knobs find their way into the delicate signal path and cause degradation (Bad vibrations equal bad sound). With the signature knobs micro vibrations from the C37 concept of wood, bronze and the lacquer itself compensate for the volume pots and provide (Good Vibrations) our ear/brain combination like to hear…way better sound!!

Source: https://bobbyowsinski.blogspot.com/2012/05/485-volume-knob.h...

I get nerding out on stuff but I don't get doing it at the age of the guy in the story. I thought as one got older one started to see the foolishness in this sort of excess. You can't take it with you. And in the end you see what became of it. Split up and sold off to strangers for a fraction of what it cost.

I had a similar experience, though the other way around.

I was listening to some speakers at a relatively high end store (they sold 10k$ CD player power supplies, along with a selection of more reasonable gear), where they'd only have one set of speakers in the room at a time to prevent passive effects on the sound. (which is sort of reasonable, but a lot of work). So they bring in the Magneplanars and the (incredibly inappropriate) amp I was interested in, wire them up, and within 5 seconds I know they're out of phase, and then in another 30 seconds, pretty strong clipping.

Sales person was going on about how good they sounded.

Yup. When I used to do studio recordings as a musician, most studios have A/B/C speakers for mixing. They have the nice speakers usually on concrete breeze blocks which is what you do your first mix on, and those are equivalent to entry-level-ish audiophile speakers but not super-expensive, then they have the B speakers which are a bit worse and then they have the depressing C speakers which represent what people usually have at home. Even super-expensive studios that will happily drop 10s of thousands on a valve preamp or Neumann mic don't use any kind of fancy cable or unobtanium plugs or anything. Just regular hard-wearing well-shielded audio/speaker/whatever[1] cables depending on application.

[1] There are some differences based on whether the cable is going to carry just audio or audio+phantom power and also whether it's line level or speaker level or whatever it's called. It's been a while.

And now they also mix it so it sounds good on earbuds and even phone speakers.

The age factor is so real. Once you're in your 40s, there's just no point, your ears are probably the limiting factor.

The positive is that you can just embrace the convenience of 'good enough' compressed audio and wireless headphones.

When I was a kid, the whine of CRTs was genuinely annoying, and those 'keep pests away' things hurt when they went off. I was looking forward to not having to experience that as I got older.

Now that I'm middle-aged, I can tell there's a little loss around the vocal frequencies... but damn if those old tubes and pest devices aren't as annoying as ever. Ears are weird.

I had a magic skill when I was in high school: I could walk into any computer lab and tell you exactly which monitors were on (when the computer was off). I believe this is around 15K.

it looks my hearing drops off between 13k (noticeably quiet compared to 12k) to 14k (can't hear it at all).

A very old NTSC TV will be 525 scan lines @ 30 frames / second => 15,750 hz.

The source of the sound is the transformer which resets the scan line back to the original side of monitor.

Why is it more noticeable when the computer isn't sending a signal, but the monitor is on?

Hah reminded me of when I was a kid walking into the living room with a few people around many times and turning off the TV (crt of course) that was just showing a black screen. It was so loud and obvious to me. Now all the TVs seem to have bizarre screensavers

I also seem to have beyond normal hearing, and can hear some electrical devices or high pitched sounds where others don't seem to.

Last year I was in a mall where they had a Tesla store and it was emitting a horrible high pitched sound.

Where I live some houses have Seagull scaring devices and they also emit a horrible high pitched squeal which I'm guessing others can't hear, otherwise it would honestly drive you nuts.

> Last year I was in a mall where they had a Tesla store and it was emitting a horrible high pitched sound.

Some malls do that deliberately to get rid of teenagers.

Not so sure about that, mixing engineers have to do very precise manipulation of sound and there’s plenty of them working well into their 40ies and beyond. While of course aspects of your hearing deteriorate, it should still be pretty simple to pick out the artefacts of compressed audio if you’ve gotten attuned to them at a younger age… At least for heavier compression, something like a 320kbps MP3 or 256 AAC is hard to distinguish from lossless but that’s also true for young folks.

Even young audiophiles can’t pass an ABX for high quality (192kbps+) lossy compressed audio. It’s perceptually transparent.

I had previously toyed with the idea of marketing "organic" audiophile speaker cables. The ad copy would have been that the cables were harvested from veins of copper dragons that lived in faraway mountains. That the sound would be warmer and richer than ordinary, industrially produced artificial speaker cables, which tend to sound harsh.

It's bad enough that some audiophiles make it a point to not talk about being an audiophile because they don't want to be the associated with that foolishness.

And "audiophile" network switches that are rebranded tp-links

My favorite from when I used to be around this stuff was a CD demagnetizer.

Do you remember the green marker meme?

https://www.snopes.com/fact-check/bewaring-of-the-green/

It wasn't a meme, it was a real product. A matt green paint pen.

In my foolishness I bought such a pen. It was a fun thing to try with friends for maybe £10.

Freezing CDs was another one. We tried that too. We were probably mildly stoned for that.

This was the early nineties. It was an interesting time in Hifi. 1-bits DACs and other fun marketing blurb.

I listen to CDs almost daily, on the same amplifier I had back then. I still have the CD player but it needs a new laser and controller board.

I laugh to myself every time I pull out a CD with a green edge. It's a lovely reminder of my young self and my friends in our late teens.

Ah yes, DirectStream Digital. I think the math behind that was solid but there wasn't really any point because PCM was totally sufficient. The company I was working for made AD and DA converters for recording studios and film so we were adjacent to all the insane HiFi stuff but didn't really interact with it. We did get bug reports that were real but effectively not visible, I learned a lot about debugging from watching my boss work on those.

I remember being an electronics store once and seeing some cables intended for audio that described themselves as being "low oxygen" cables. My god, the nonsense that people fall for!

Out of all the ridiculous things, this one is actually not completely ridiculous. For low temperature physics applications, Oxygen-Free High Conductivity (OFHC) Copper is the only material that is sufficiently thermally conductive at low temperatures. I’m not an audio person, but I have a hard time imagining it would make much of a difference at room temperature; maybe similar performance with a slightly thinner cable?

Avoiding corrosion may be another benefit, although I'm not sure how much effect it has in practice compared to regular non-oxygen-free copper.

Finely stranded, tinned copper marine wire would be the ideal for corrosion resistance.

My walk in freezer sounds amazing though

To be slightly fair it’s like food, make it look better and it tastes better, but this dials it to 11

Wait, wait, wait! There's stereo cream?

Do I apply it to the speakers or the walls or the listeners or what?

Ears. Inside and out, just try not to get it in your hair.

> magic creams

Hifi hand lotion: Deep down you know spending this much for better audio is masturbatory, skip the middle man.

> High-end hifi is full of grift. It literally relies on people with more money than sense who can be persuaded to spend a fortune on components and extras that either make no difference to the sound or make it objectively less accurate.

Replace "hifi" with any other product and the sentiment remains the same. High-end houses, high-end cars, high-end clothes, high-end food, high-end technology... the ostensible quality of the product is entirely divorced from the price, because the actual product isn't the speaker or the handbag or the smartphone or etc; the real product is social signaling via conspicuous consumption.

To be fair, with most of those, you're paying for a piece of art to some extent. I don't think anyone buying $500 cables thinks the cables themselves are worth that, they're buying them because they expect some tiny increase in sound quality which measurably and provably doesn't exist. Someone buying a $10k sweater isn't buying it for the engineering in the material, but for the perceived artistic value. Of course, there's also a grift involved here, where fashion brands can pass things off as having great artistic value just because they're associated with the brand. But at least the perceived value is subjective and not coming from something that can be measured not to exist.

At MIT, I had a friend who wired his speakers with flat ribbon cable, alternating conductors so as to minimize impedance.

Me, I used 150 foot 18-gage twisted pair when I put my speakers down in the courtyard. I can't say the sound was perfect, but it was at least pretty good, which tells me 20 feet of the same would be plenty good inside a room.

(Yes, IANAaudiophile...)

Piker. A rich, truly obsessive audiophile wouldn't use copper, but rather 6nines annealed silver wire for those speakers.

Were these wires shielded in any way?

Speakers are high-current, low-impedance loads. They won't pick up any significant noise, so shielding is entirely unnecessary.

Yeah he didn't have any shielding other than the insulation plastic on teh outside.

The high currents might induce noise inside other parts of your electronics ...

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