I'm glad you are taking all the feedback in stride but I think this is a great idea. For all the people saying signing up is a big commitment, buying or ripping off (as thats what everyone I know did in college who couldn't afford it) Ableton Live or for me using fruity loops or a linux knockoff is a big commitment either financially or learning the ins and outs.
At the very least, this takes away some of the
a. intimidation of merely experimenting with music to someone curious about it, and could be a leeway to people investing in desktop based software or a group of users could grow with you as you go along.
b. financial commitment or technical search/compare contrast, and download/ripoff of existing software and finding compliance with operating systems.
Most of your feedback here is probably going to be from experienced music makers but as an Electrical Engineer who loves music, and playing with music is only something I have to do in my spare time since I work two full time jobs, this is really cool and allows me to play with stuff easily.
It also enables me to login and work on this at my work computer, so even if I make a sample, I can send it to myself elsewhere.
I think this is a great idea. There is some cool music software and I have audactiy, ardour, ableton live and fruity loops but the webapp idea is actually a great one and there are some huge advantages here. You are
1. Lowering the barrier for entry level music makers and making it a little less intimidating to be honest
2. Allowing increased access so people can play and edit in their spare time or on a lunch break at work, or just pull it up to play around with friends at a coffee shop on their laptops.
Going through the process of finding downloading/paying for a piece of music making software is alot of work and might otherwise deter two people from sitting down and just mixing up something on the fly quickly
3. I know alot of highshoolers who would use this in school that can't bring their laptops to school.
4. On a globalscale, feedback here is really underestimating the lack of ability many people in many countries have to liscenses to good music making software we have in Westernized society. Now anyone who has internet or the future phone apps can have access to this without having to torrent software or be a linux guru to know about the free distros out there. This is a huge advantage.
5. As shown in another comment, someone who does speech processing has already found this to be advantageous, there are some clear uses outside of experienced DJs and music makers for other industries. Watch your demographic closely because there could be some great uses for this otherwise that come through in later funding rounds if you need support to scale.
6. The basic features despite immediate feedback from people that it seems pretty basic, is not a bad thing when you are starting out in my opinion. You can grow and respond better with your user group than having a panel of overhwleming options to anyone other than already experienced music makers. Their feedback is one of the most important, but I think your initial userbase is going to grow with you and that's not a bad thing.
Like everyone else said, I would put a cool little mini walkthrough tutorial of how to make a cool 20 second sample with your software and have it on the front page so people could actually click through see some of the features and make a little sample or something. If they want to save the sample to edit, share or collaborate, then they can be prompted to make a login.
When you roll out to the paid app, provide a discount if people to invite, share on twitter, fb etc and provide a link for them to do so. It sounds cheesy but don't be ashamed to have your own users advertise.
Don't be discouraged by the feedback of experienced users. This is a really good idea.
scale for phone apps and make a twitter account.