Totem Dreamcatcher sub re-amp

[KenM10759]

I had picked up this Totem Dreamcatcher sub to mate with the KEF Egg speakers I have on my benchtop at work. It was cheap because the seller said it had a buzzing noise. I liked it because at 7-3/4" wide by 10" long and 11" tall it's the right shape to fit where I need to put it. Of course it's hardly a true subwoofer and probably doesn't even hit the 30hz spec. He was right, it had an incurable buzzing.

Totem had no parts and no schematic, so my electronics wizard friend couldn't fix the Bash amp that's on a 6" x 6-1/2" plate. I could find no other amp anywhere near the 200w spec, so after 8 months of looking at it I today adapted a Dayton SPA250DSP amp by making a 1/2" thick piece of MDF to cover the opening and hold the 7-1/4" x 9-1/2" plate amp. Because the amp is bigger than the opening and the cabinet has twin ports up near the top rear, I have the plate hanging down below the bottom of the cabinet by almost 3". My son whipped up 3-1/2" riser to stick on the bottom, I'll paint it tomorrow and stick it on the bottom of the cabinet with construction adhesive. Done.

What I want to ask the experts here about is stuffing the cabinet. I don't know if it ever had anything in it, but when I took the stock Bash amp off there was none. I put some loose poly-fill in, filling perhaps 1/2 the volume, maybe a little more. I had hooked it up in my office to connect it to my PC and my office sound system to dial in the DSP with the Dayton app. It really sounds remarkably clean and responsive with the PEQ curve I set.

Do you think I should remove the stuffing or leave it? As I said, I don't know if the original owner had tried repairing the defective amp and removed some, but I'd never seen a small sub, sealed or ported, that didn't have some amount of stuffing in there. Pictures tomorrow of the finished unit, after the riser is painted and installed.

 

[KenM10759]

Total investment turns out to be $342.79, for the sub, amp, and mounting bracket. Sounds incredible! It's only a 7" driver but man it pounds hard down to about 30hz.

 

[Pogre]

That's really cool. That amp looks like half of the unit!

 

[KenM10759]

That's really cool. That amp looks like half of the unit!

Nah, but it's definitely bigger than the little flush plate amp that it came with and couldn't be fixed. Being able to control the output so finely is a joy. I had dialed it in rough at home with the app they have for it, on my home PC. I did that in my office. The gain from being under that workbench was so much that I've had to dial it back by -8dB and it might need just a bit more.

 

[KenM10759]

I'm surprised at the reaction to this at work. The shop I work in is in the corner of a large commercial building, another floor above separated by about 16 feet and at least a foot of concrete & steel. We're walled-off from the 'general population' of the workforce, but we have several types of engineers visit daily to discuss work we're doing.

There's just 3 of us. I play mostly country music at lower volumes during much of the day, majority rule. One coworker leaves around 2:30pm, the other by 3. I'm there until at least 3:30 and it's during that time I'll play alt rock, jazz, and blues. I've noticed in just a few days of play that I now have more and curious visitors coming in. Comments about the sound quality (because I've now turned it up quite a bit) is the second thing I get, right after broad smiles. I gotta take it easy, they could shut me down and make me take it all home at any moment if I offend anyone. My two coworkers have been there longer and both have 'sound systems' comprised of plastic speakers and "sub", and the other a 90's boombox connected to his phone by 3.5mm analog.

This little system just obliterates either, and they both admit it readily. I think they're the ones telling other people to come hear it!

 

[TLS Guy]

Total investment turns out to be $342.79, for the sub, amp, and mounting bracket. Sounds incredible! It's only a 7" driver but man it pounds hard down to about 30hz.

View attachment 31466

Since it is a ported sub, 50% of the internal surface should be covered with sound treatment. I would bet the sub already has some if you look hard.

As the sub is ported you should not really be using Eq, at least to not extend the bass response. Ported cabinets rapidly decouple from the driver below F3. So if you Eq, you just get useless large cone excursion below F3 which will damage the driver.

 

[KenM10759]

Since it is a ported sub, 50% of the internal surface should be covered with sound treatment. I would bet the sub already has some if you look hard.

As the sub is ported you should not really be using Eq, at least to not extend the bass response. Ported cabinets rapidly decouple from the driver below F3. So if you Eq, you just get useless large cone excursion below F3 which will damage the driver.

It does have sound damping on the inside and the port tubes for the twin ports extend nearly to the front baffle.

I absolutely know about how to set the DSP for this because I don't want to try and make a 7" driver try to be a 12" one.

I set the cutoff at 32hz with a 24dB per octave slope. There's a lot of other settings I tweaked, and it really sounds better than it did with the stock amp that had no DSP.

 

[lovinthehd]

I'm surprised at the reaction to this at work. The shop I work in is in the corner of a large commercial building, another floor above separated by about 16 feet and at least a foot of concrete & steel. We're walled-off from the 'general population' of the workforce, but we have several types of engineers visit daily to discuss work we're doing.

There's just 3 of us. I play mostly country music at lower volumes during much of the day, majority rule. One coworker leaves around 2:30pm, the other by 3. I'm there until at least 3:30 and it's during that time I'll play alt rock, jazz, and blues. I've noticed in just a few days of play that I now have more and curious visitors coming in. Comments about the sound quality (because I've now turned it up quite a bit) is the second thing I get, right after broad smiles. I gotta take it easy, they could shut me down and make me take it all home at any moment if I offend anyone. My two coworkers have been there longer and both have 'sound systems' comprised of plastic speakers and "sub", and the other a 90's boombox connected to his phone by 3.5mm analog.

This little system just obliterates either, and they both admit it readily. I think they're the ones telling other people to come hear it!

I admire your fortitude....country music much of the day would drive me absolutely bonkers.

 

[KenM10759]

It does me too, but for the sake of peace and acceptance (I'm the FNG with only 11 months under my belt), I give in to make them 2 guys like me better. There WILL BE a day when...

 

[TLS Guy]

It does have sound damping on the inside and the port tubes for the twin ports extend nearly to the front baffle.

I absolutely know about how to set the DSP for this because I don't want to try and make a 7" driver try to be a 12" one.

I set the cutoff at 32hz with a 24dB per octave slope. There's a lot of other settings I tweaked, and it really sounds better than it did with the stock amp that had no DSP.

As far as I can tell F3 is around 32 Hz, so you have put the high pass filter at the correct frequency. It is usual to use a 12 db slope to protect the driver. So with your setting you have roll off at 48 db per octave as the sub slope is 24 db. So with a 12 db slope on the high pass the combined 36 db per octave slope might give you a little more bass extension. The other alternative is to move the high pass down to 25Hz and keep the 24 db per octave slope. I think that would still protect the driver fine. You might want to experiment with that.

 

[KenM10759]

I will absolutely try those suggestions! Thank you!

It just occurred to me that when I initially set it up in my office I had the 24dB slope but put it back at the default of 12dB before bringing it to work. That must be why it sounds so damned good.

 

[neildorin]

I have the exact same Dreamcatcher sub and mine has started producing white noise after running for about 5 minutes. The noise itself doesn't increase or decrease in volume with adjustments to the volume/crossover controls. Turning the amp off and back on again will clear the noise for a while but it always comes back.

Can I ask, do you think theDayton SPA250DSP is worth the additional cost over the SPA100-D (which basically looks like a direct replacement for the BASH amp that is currently in the dreamcatcher sub)? From what I can tell the original amp was 200W peak and 100W RMS.

How much did you adjustment did you do with the DSP?

 

[TLS Guy]

I have the exact same Dreamcatcher sub and mine has started producing white noise after running for about 5 minutes. The noise itself doesn't increase or decrease in volume with adjustments to the volume/crossover controls. Turning the amp off and back on again will clear the noise for a while but it always comes back.

Can I ask, do you think theDayton SPA250DSP is worth the additional cost over the SPA100-D (which basically looks like a direct replacement for the BASH amp that is currently in the dreamcatcher sub)? From what I can tell the original amp was 200W peak and 100W RMS.

How much did you adjustment did you do with the DSP?

Your unit most likely has a noisy resistor or solid state device, so it is reasonable to change the plate amp. Any plate amp of the correct power will do, as long as it fits. It must be a tight fit. Since that is a ported sub your Eq is limited to where you set the high pass to protect the driver. F3 is 32 Hz, so it not a floor shaking sub.

 

[KenM10759]

I have the exact same Dreamcatcher sub and mine has started producing white noise after running for about 5 minutes. The noise itself doesn't increase or decrease in volume with adjustments to the volume/crossover controls. Turning the amp off and back on again will clear the noise for a while but it always comes back.

Can I ask, do you think theDayton SPA250DSP is worth the additional cost over the SPA100-D (which basically looks like a direct replacement for the BASH amp that is currently in the dreamcatcher sub)? From what I can tell the original amp was 200W peak and 100W RMS.

How much did you adjustment did you do with the DSP?

Changing to the Dayton Audio SPA250DSP plate amp required adding their optional vented housing and a piece of 1/2" MDF of the same width and height, plus a 2" riser because the amp is bigger than the sub!

It worked GREAT and having the DSP is very much worth the extra expense. I use the same plate amp on a reworked Miller & Kreisel V-90 to which I also modified to take an SB Acoustics SB34SWPL-76-4 driver. The SPA250DSP's app works so good for setting every parameter. I love it! Been a couple of years now, and the modified Dreamcatcher sub is sold to a friend who loves it. I still have the M&K V-90 that @TLS Guy helped me choose the driver for, and it's SO GOOD that I can't imagine ever letting it go.

 

[neildorin]

Changing to the Dayton Audio SPA250DSP plate amp required adding their optional vented housing and a piece of 1/2" MDF of the same width and height, plus a 2" riser because the amp is bigger than the sub!

It worked GREAT and having the DSP is very much worth the extra expense. I use the same plate amp on a reworked Miler & Kreisel V-90 to which I also modified to take an SB Acoustics SB34SWPL-76-4 driver. The SPA250DSP's app works so good for setting every parameter. I love it! Been a couple of years now, and the modified Dreamcatcher sub is sold to a friend who loves it. I still have the M&K V-90 that @TLS Guy helped me choose the driver for, and it's SO GOOD that I can't imagine ever letting it go.

Thanks for the feedback. I'm actually a woodworker so I would probably build a matching riser and veneer it with matching mahogany to make it look as OEM as possible. Having the amp sit outside the body of the sub in a vented housing would be no big deal.

I'll order up the SPA250DSP then!

I also have a Monitor Audio RSW-12 with a bad power supply so this gives me hope that if I'm not able to source a replacement power supply for it that I can just order the appropriate Dayton plate amp to get that working again as well.