HELP!
The static is droning, and the volume is deafening, but the camera didn’t capture the full scope of this. The best example of the static in this video is when I play the theme song. I’m so lost right now. I’m wondering, is it possible that the sounds on my sound kit itself are staticy when amplified?
Specs:
Crix Sound Kit
Speakers: 2 X 3.25" SQUARE PIEZO TWEETER
AMP: 8 Watt Mono Amp
My speakers are wired in Parallel.
Piezo speakers are generally ■■■■ sound quality anyway. The link you posted to them has no info on their rating but i’m guessing they’re too-low impedance.
The Scosche have the same problem, they’re 4ohm speakers in parallel giving you a total impedance of 2ohms. The amp is looking for 4ohms, try it with just one speaker.
Hey there, Jack - thanks for the speedy reply. I tried just one speaker (one of the two Scosches in the Sync Gen) and the static remains. Would you recommend trying to wire all 4 speakers in Series?
Failing that, what other ideas do you (or anyone) have? I am ALL ears.
Wireing them in series would compound the impedance, making two speakers be 8ohms. The way mburkit’s tutorial has it is two 8ohm speakers in parallel giving a total impedance of 4ohms. According to the tutorial thread RP’s chip needs 8ohm speakers and the amp needs 4ohm impedance. Dunno if crix’s chip is the same way but I think your next step is to try two 8ohm speakers.
These look ok?
If so, it’s gonna be a little bit before I can shell out for these; gotta make rent first.
Far as I can tell, audio electronics makes no sense to me. 
You want 8 ohms man wire your two 4 ohm speakers in series and then try it. You don’t need the tweeters.
I’ve tried that, as mentioned in the video. The static’s still there.
Like we were discussing in the chat room. I do believe that you should add a little more battery power to the amp. The batteries need to power the amp and speakers… More is better not too much more though 
I’d agree with this, what type of voltage are you putting on your amplifier?
It sounds like you’re hitting the rails in the YouTube video. Try using a 9 or 12V power supply on the amplifier. Do NOT use a single power supply for both the audio chip and amplifier (aka don’t put 12V on the audio chip)
Understand that there is always going to be some distortion when using these chips and amplifiers. In effect, you’re only amplifying half the signal while passing the other half through to the speaker. It’s a problem that requires a lot more to fix than just a single amplifier.
I had the same problem when my battery’s got low i had one 9 v hooked to my amp, and it would kill it in about 30 mins my fix was to try hooking the max power the amp can take i went all the way to 18 v on my amp and it sounds a lot better it nerve racked me to no extent but it solved my problem though
Also do you have a switch disconnecting your amp power when not in use?
Ya i need one of those, so if anyone has any good ideas for a switch between the power for the amp i would love to hear it. But see Ronnie, looks like alot of ppl think it could be the power too hopefully we helped!
I’ve got 8 AA’s (12 v) on the amp, and 2 AA’s on the sound chip. After talking to Biber, I have also tried 2 9v batteries (a total of 18v) on the amp, with the same staticy results. Also, since I’m only still testing things, I haven’t wired up a switch to kill battery to the amp, though I will be implementing this when I’m happy with the sound.
See above.
Still stymied… Anyone else?
I’d try getting a new pot if mines up too high like that is sounds like that too.
two bad potentiometers, on two different amps?
Besides, I’ve got a ton of potentiometers lying around here, and it’s not them.
Any other ideas? Anyone?
You’re probably stuck just waiting until you can get the right speakers for it. I tried to use 4 ohm speakers on my RP sound chip and couldn’t find any way to make it not sound like shit, either.
Couple things to try:
Does the audio sound good coming directly off the sound chip? Try hooking your speaker up directly to it rather than going through the amplifier.
How does your amp sound when trying to amplify something else? If you have a headphone plug you don’t mind cutting up, try connecting your iPod or something to amp and see if that works well.
If both of those work properly, then the issue is more complicated than you think. I don’t suspect it will be the case tough.
You need to work through the individual systems to figure out what is causing the issue. Once you try these things report back.
Yeah, that’s probably the next step, and that’s gonna be whenever I have some petty cash to dispose of.
The audio does indeed sound good coming right off the kit, as mentioned in the video. I will get myself an old headphone jack and cut that up, to see if the amp still sounds scratchy from that..
It almost sounds like square-wave distortion. I had guessed that the piezo’s were not presenting a sufficient load to the amplifier (the impedance changes with input voltage on some of them) but given that the output with a standard speaker is still resulting in distortion I’m wondering if there’s too much signal at the input stage of the amplifier.
I believe I had the same problem. Sound with the sound chip driving the speaker(s) sounded fine, but the volume was just too low. Hooked up an amp and the sound was badly distorted. The volume control also did not work as I expected - little or no control of the volume. I tried hooking up either sound chip speaker driver output or the sound chip’s “PWM” output and the results were the same (V1.2 sound chip). This was with a common ground between the amp and the sound chip.
It appeared that the problem was related to how the speaker driver in the sound chip works - you are not supposed to ground either side, as the speaker is driven differentially. So there is no simple way to connect the speaker output to many single ended amp inputs. The output of either side to ground is not acceptable. An amp with differential inputs (I don’t have one of those) may work fine.
I did finally “float” the amp by using a separate battery and then connected the floating amp’s ground to one of the sound module speaker outputs and the other speaker output to the amp’s input. This worked fine and there was little or no distortion. I didn’t want to use separate batteries and it is kind of a kludge and I haven’t gone back to verify exactly what the source of the problem is.
Hopefully I will get back to that in a few weeks and check out the signals with my scope and see what is really going on!