Finding power outputs for a sound system and getting a subwoofer to match

Lord Evermore

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My father died last year and one of the things we found in the piles of stuff he refused to throw away is a no-name sound system. The only information on it is "MODEL: DHT-600" and "5.1 Home Theater System". I can't find anything about this model. The speakers have nothing at all on them. I finally got around to testing it, and surprisingly it works. But the subwoofer was not to be found anywhere, and with no information I have no idea what size/power sub I would need to match it. Have to figure out where to get one cheap as well. I don't expect it's a super powerful system but almost certainly far more than I need for my desk and PC, and I could get an entire set of speakers that works fine for my computer for the price of just a big sub.

If I were to disassemble the unit, is it possible that components inside would provide what I need to get a matching sub? Or if I get information by disassembling the speakers could I make an assumption about what sub would go with it?

The one problem I had was plugging it into the cheap sound card I have, because all the rear channel audio just went to the front speakers, and the center and sub audio went to the left front speaker. The card is 5.1 capable but it's an ancient Cmedia chipset that barely works in Windows 10, so even though it allowed me to specify that it's a 5.1 speaker set, there's a good chance the drivers aren't actually working for 5.1 functionality. I may re-enable the on-board mainboard audio chip to try it there, but that chipset has never worked properly either. At random after a reboot, the left channel in stereo will just not work. But if I swap drivers to the Microsoft driver, then back to the Realtek driver, I'll get audio for the left channel, but it actually plays on the right speaker. And the right speaker always works. I had the mainboard for a couple of years before I discovered this issue and absolutely nothing I did fixed it, and I even destroyed a nice set of speakers thinking it was the speakers that were faulty.

Even if this set is too much for my small room and PC, as long as it works and we can get a sub, my brother-in-law will probably want it. It is annoying that the amp has a fan, though.
 
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Doomlord_uk

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You can get a more powerful sub and just turn the gain down to match, so it's not necessary to get an exact match. Sounds like one of those systems sold in department stores so it's probably not high quality. Poke around on eBay and you'll probably find something for whatever your budget is. [Edit] - btw sounds like a Pro Logic setup. It doesn't really do 5.1 (which would be Dolby Digital). Never heard of a card that could output Pro Logic... so you may not be able to get this to work even with 2.1. By all means try, but be prepared to flip the sub and dump the system. Pro Logic gear basically has no value nowadays except for garage/workshop or similar places.
 
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Lord Evermore

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Well it has separate connectors for each pair of channels, so I don't see how it would not really do 5.1. It seems like the card itself is just outputting everything on the single cable even when configured for 5.1. But when I was looking at information on subs I saw stuff about one needing more power and it was damaged (and I assume the sub on this was only powered by the amp, not a separate power supply). And figuring out turning down the gain to prevent problems is more than I care to bother with. But if I could tell my brother-in-law he can just pick up a matching used sub for $20 on eBay or something, he might want it. He works in a different state 3 weeks out of 4 and lives in a small trailer there. I'm not sure he actually even has anything that he could plug it into though.

I'll probably just get a PC speaker setup that costs like $80 for the whole thing, for myself, with a newer sound card or USB DAC (I'm loathe to get a USB DAC though and have yet another box laying on the desk).
 

Cool Modine

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and I assume the sub on this was only powered by the amp, not a separate power supply
What’s the jack/cable type for the sub out? If it’s an RCA jack then it almost certainly used a powered sub. This bodes well for you; it’s more likely that any standard sub could work.

If it’s any kind of thing that takes bare speaker wire, your assumption is good that the amplifier powers the sub. But that’s also bad because that’s nonstandard for home AV gear, and harder to work with.

If the subwoofer is none of the above, you’ve probably going some kind of proprietary tomfoolery, which also doesn’t help you.
 
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Lord Evermore

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What’s the jack/cable type for the sub out? If it’s an RCA jack then it almost certainly used a powered sub. This bodes well for you; it’s more likely that any standard sub could work.

If it’s any kind of thing that takes bare speaker wire, your assumption is good that the amplifier powers the sub. But that’s also bad because that’s nonstandard for home AV gear, and harder to work with.

If the subwoofer is none of the above, you’ve probably going some kind of proprietary tomfoolery, which also doesn’t help you.
All the speakers are RCA outputs on the amp, but then they're bare wire going into the speakers themselves, and the satellites are all exactly the same small units, like little desktop speakers that might be 5W each, or even less (the driver is only about 2 inches). I could put a clamp meter on the wire to a speaker to measure the power with it cranked up (or measure directly on the wires) but I'd have to figure out how to convert that to "speaker power" RMS.

This is probably all entirely a waste of time from the "is it worth it" perspective of the speakers and amp having any value, but it's interesting and fun and gives me something to do.
 
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Lord Evermore

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Damn. These truly do seem to be trash, which my father probably paid a lot of money for and bragged about to somebody because he was that kind of guy, thinking "they must be good because even though they're not a name brand they're expensive". Then he probably kept them for a while because he couldn't really tell the difference and thought they were super powerful, and finally stuck them in a box during a move and never thought about them again for 20 years and switched to headphones or just bought an even more powerful system for the living room TV.

I measured 3 ohms resistance, with 1 amp peak going to the speakers, and the meter jumping from 1V to 2V while playing Rammstein from my phone with all the volume controls turned to maximum, and the same from my laptop. Each individual channel did work just fine, though the plugs were flaky and I had to twist and jiggle them to make them work, so 5.1 ought to work with proper output from a PC. So maybe 2W actual on the satellites, assuming the meter isn't really reporting reliably for the resistance. Maybe they're rated for 5W so my guess seems good there.

For fun I tested the system on my PC. It's a Blu-Ray home theater system acting as a receiver with its own speakers, supposedly 1000W. With everything at maximum I saw the sub peaking at 20V and 7A, and the satellites at 7V/3A (3 ohms according to the labels on all). I'm not sure I believe 1000W total, or even 500W, even with all 5 speakers and the sub going at maximum but it's still quite loud.
 
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Paladin

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It sounds like your basic no-name Home Theater In a Box type setup where the speakers are all tuned specifically to the output of the low power amp in the system. You could probably look for any left over cheap speaker set at a pawn shop that has a red and black wire going into the 'subwoofer' directly and try splicing a connector onto it so it will plug into your system and see how it sounds. Any 'computer speakers' that came with a set of 2 desktop and 1 woofer sould probably work to get you what you need. Just wire the woofer into the sub output and see how it sounds. The system likely has a crossover so that the woofer was getting a huge amount of mid-bass that would normally go to the normal speaker level outputs because the satellites likely have tiny paper 2 way cones and that's it. You could get a Klipsch Pro Media 2.1 system for $80 or so on ebay and do just fine, probably better than this system, as long as 2.1 audio is good enough for you. It's about the same anyway since there is no way you can get dolby digital or anything with real discrete audio surround channels from that old setup. If by some miracle, you get a 5.1 output from your computer working via 6 analog outputs... well that would be shocking. As you say, drivers are very hard to get going for that kind of thing these days.