Well, iron law....
Can't bend pysics to our desires
It is what it is.
Hope you find a mid point between expectations and reality.
Can't bend pysics to our desires
It is what it is.
Hope you find a mid point between expectations and reality.
I've figured out two main problems with my system (other than messing up the dimensions when I designed it):
1) The amp board (https://store.sure-electronics.com/product/AA-AB33511) needs a pre-amp; even when getting sound from bluetooth adaptor or mixer. However, the pre-amp I have (https://www.amazon.com/gp/product/B081YPCQHC?) is introducing a hefty amount of buzz into the mix. I tried a normal battery bank, and adding capacitors on the power input and that didn't help. My signal path is: Bluetooth adaptor/future mixer -> adau1701 DSP board (https://store.sure-electronics.com/product/658) -> pre-amp -> amp -> Speakers (my tops have a crossover in each of them). How should I increase my signal input into the amplifier? Ideally running on 12V, (though could be 50V or 5V if necessary)
I'm looking at https://www.aliexpress.us/item/3256...BusinessMode":"retail"}}&gatewayAdapt=glo2usa and https://www.aliexpress.us/item/3256....0.0.306238daJCeyQX&mp=1&gatewayAdapt=glo2usa as potential replacements... if you think they would help.
2) My speaker has insufficient bracing - especially the back panel I made to be removable. That's fine - it's a prototype for that very reason. THe back was flapping by at least an 1/8 at high volumes.
Otherwise general feedback request:
This is my DSP in Sigma Studio - separating lows and highs at ~130 Hz, and high passing with a first order filter at 35 hz the sub. I have no clue what i'm doing; it's working but could it be better? Probably.
1) The amp board (https://store.sure-electronics.com/product/AA-AB33511) needs a pre-amp; even when getting sound from bluetooth adaptor or mixer. However, the pre-amp I have (https://www.amazon.com/gp/product/B081YPCQHC?) is introducing a hefty amount of buzz into the mix. I tried a normal battery bank, and adding capacitors on the power input and that didn't help. My signal path is: Bluetooth adaptor/future mixer -> adau1701 DSP board (https://store.sure-electronics.com/product/658) -> pre-amp -> amp -> Speakers (my tops have a crossover in each of them). How should I increase my signal input into the amplifier? Ideally running on 12V, (though could be 50V or 5V if necessary)
I'm looking at https://www.aliexpress.us/item/3256...BusinessMode":"retail"}}&gatewayAdapt=glo2usa and https://www.aliexpress.us/item/3256....0.0.306238daJCeyQX&mp=1&gatewayAdapt=glo2usa as potential replacements... if you think they would help.
2) My speaker has insufficient bracing - especially the back panel I made to be removable. That's fine - it's a prototype for that very reason. THe back was flapping by at least an 1/8 at high volumes.
Otherwise general feedback request:
This is my DSP in Sigma Studio - separating lows and highs at ~130 Hz, and high passing with a first order filter at 35 hz the sub. I have no clue what i'm doing; it's working but could it be better? Probably.
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I moved away from using Sure/Wondom parts a while back, because it's a headache trying to trawl through their documentation...
Would've assume that DSP board could give enough signal output to drive the amp, but can't find any numbers stated for its output
And the amp could have switchable input gain - the specs suggest so, with "0.876/1.44" stated as input sensitivity, and I've seen gain switches on other boards... but again not detailed in the spec sheet
If you do add small preamp boards that need power conversion, consider getting a few Isolated DC-DC converters - reduces the chance of introducing noise
But really, I'd look to simplify things and maybe even change DSP instead of adding more parts. It could seem a bit pricey but knowing you have reliable parts that can be reused in future systems could be considered an investment
Would've assume that DSP board could give enough signal output to drive the amp, but can't find any numbers stated for its output
And the amp could have switchable input gain - the specs suggest so, with "0.876/1.44" stated as input sensitivity, and I've seen gain switches on other boards... but again not detailed in the spec sheet
If you do add small preamp boards that need power conversion, consider getting a few Isolated DC-DC converters - reduces the chance of introducing noise
But really, I'd look to simplify things and maybe even change DSP instead of adding more parts. It could seem a bit pricey but knowing you have reliable parts that can be reused in future systems could be considered an investment
Part of the issue with that is I didn't find boards that take 50V input other than those. (54V actual/peak).
I asked about the input sensitivity; but some of their other boards of the same family only say 1.44 for sensitivity so I suspect that may be the issue - and the APM2 max output is 0.9V.
For the pre-amp I don't think it's the power input introducing noise, as I tried also running it directly on 3 AA batteries (which I think should be noiseless right?) and added a 100uF capatitor to the DC input which changed nothing.
I'm absolutely open to suggested pre-amps/DSPs/amps given my existing batteries. Looking at the T.racks mini I didn't see an output voltage listed, but would guess it would also be in the 0.9 range.
I asked about the input sensitivity; but some of their other boards of the same family only say 1.44 for sensitivity so I suspect that may be the issue - and the APM2 max output is 0.9V.
For the pre-amp I don't think it's the power input introducing noise, as I tried also running it directly on 3 AA batteries (which I think should be noiseless right?) and added a 100uF capatitor to the DC input which changed nothing.
I'm absolutely open to suggested pre-amps/DSPs/amps given my existing batteries. Looking at the T.racks mini I didn't see an output voltage listed, but would guess it would also be in the 0.9 range.
I'm using the T.Racks DSP 4x4 mini, whilst I haven't spent too much time with it I'm happy so far - simple interface, build is tough enough, and importantly... Up to 12dBu in and out, which is 3v RMS
This means it can handle a hot input from a "pro level" mixer (I'm using a Yamaha MG06) so I don't have to be monitoring the input level for fear of clipping the DSP when getting a bit enthusiastic
For the output, I just scale down the levels - it's easier to turn things down than turn them up
This means it can handle a hot input from a "pro level" mixer (I'm using a Yamaha MG06) so I don't have to be monitoring the input level for fear of clipping the DSP when getting a bit enthusiastic
For the output, I just scale down the levels - it's easier to turn things down than turn them up
Oooo thanks - I saw 12 dBu but didn't know that can be in practice translated to voltage. Sigh. I guess I'll probably be spending another hundred bucks 🙁
Do you ever feel the need to change the DSP on the fly? I'm wondering if the mini pro might be worth it for the ability to easily swap between 3 different presets.
Do you ever feel the need to change the DSP on the fly? I'm wondering if the mini pro might be worth it for the ability to easily swap between 3 different presets.
Some additional investigation and i've noted that not only is the APM2 outputting a 'low' line level... it's also the source of the noise I was amplifying with the pre-amp; so other pre-amps would be no help.
To get the t.racks 4x4 or 4x4 pro ... sad about the $130+ price tag (shipping aint cheap).
To get the t.racks 4x4 or 4x4 pro ... sad about the $130+ price tag (shipping aint cheap).
I'd not seen the 4x4 Pro before, the switchable presets is an interesting option - I could see that being useful for creating an "Efficient" setting and a "Party" setting to switch between
The 3034 thing worked a treat. Bluetooth range wasn't an issue with the provided external aerial. The phone app allowed volume and dsp controls. 6-24v iirc, which you can easily make with a dc-dc, as it's not even half an amp. The need for 6v+ makes me think it's regulated down to 3.3 so not pointing towards a huge output. It's a cheap quiet BT dsp though, and you could buy a further preamp board for a couple of quid. £20 all in. With some sundry items.
@friendly1uk i'm not sure what you are referring to with the 3034?
I got a T.rack 4x4 and while that gets high enough output it requires maxing out the input amplification which is adding significant amounts of noise even with nothing plugged in. But it does work!
I gave it a first minor ride (and used it at my friend's birthday where we kept it below 50% power for noise reasons) - check it out below 🙂
the two white things are off the shelf outdoor speakers (polk audio m3 I got used) while the other one is obviously one I made. I do have a second that needs to be rebuilt (I made two different designs only one of which I liked).
I ran it for about 7h at 50% volume and still had over half my battery left (and I had a spare ready to swap out)
Now to see how long I leave these in their temporary OSB boxes/till I make them into proper quality plywood... and better build quality. These were my first time using a nail gun
Gravity is all that's holding the subwoofer box in place, with the top ratchet strapped to it... and some janky controls elsewhere. The amp/control box (also does voltage conversions) is in a literal cardboard box while I figure out the best way to do it.
🙂
I got a T.rack 4x4 and while that gets high enough output it requires maxing out the input amplification which is adding significant amounts of noise even with nothing plugged in. But it does work!
I gave it a first minor ride (and used it at my friend's birthday where we kept it below 50% power for noise reasons) - check it out below 🙂
the two white things are off the shelf outdoor speakers (polk audio m3 I got used) while the other one is obviously one I made. I do have a second that needs to be rebuilt (I made two different designs only one of which I liked).
I ran it for about 7h at 50% volume and still had over half my battery left (and I had a spare ready to swap out)
Now to see how long I leave these in their temporary OSB boxes/till I make them into proper quality plywood... and better build quality. These were my first time using a nail gun
Gravity is all that's holding the subwoofer box in place, with the top ratchet strapped to it... and some janky controls elsewhere. The amp/control box (also does voltage conversions) is in a literal cardboard box while I figure out the best way to do it.
🙂
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Great work!
Importantly, how does it sound and are you happy with the outcome?
The hardest part will be deciding if you want to rebuild the setup or just use it as-is, since once the fun starts it's hard to get back in the workshop again
Importantly, how does it sound and are you happy with the outcome?
The hardest part will be deciding if you want to rebuild the setup or just use it as-is, since once the fun starts it's hard to get back in the workshop again
JBL T202DI driver and... not sure what the hornguide is - got both the driver and hornguides used locally.
I am quite happy with the outcome - other than still having noise issues. Great bass, and works amazing on the bicycle trailer - plus since it's pointing down I can use the sub to hold things; strap things to it; etc.
I definitly will be taking apart one of the tops - I like the design of the one in the pic but have a second design I had made that I don't like. But yeah... we'll see how long the OSB lasts... I do definitly want to redo it because the construction is... iffy.
One thing I did as a modification to improve it which I really like is having threaded rods going through it pulling the front and back together - it really got rid of the vibrations in the front and back with a negligible amount of extra weight. And provides spots for things to be held on top.
But I also want to upgrade the tops to 8" drivers... probably... and 100% need to upgrade to a new control box to replace the cardboard... and add lighting to the trailer... so who knows how long a rebuild will get delayed 🙂
Yep! Ultimately the deciding factor was being able to easily customize the ratio/shape to fit the trailer design - so it fully covers the footprint trailer minimizing how tall it is, helping to keep the center of gravity low and prevent tip over... and especially keeping the driver near the bottom to further concentrate the weight at the bottom.