Weak Bass from Subwoofer

J

josh logan

Audiophyte
I have a Kef psw2010 connected to a denon 3805 and find the bass that is produced is somewhat weak and not loud at all. I hooked up a friend's Yamaha 8" sub just to see if it was an issue with the avr but it pounded much louder and harder while only having the volume about halfway up compared to my Kef. I have the levels maxed out on the sub and the settings on the avr are maxed as well. I have gone through the settings and the speakers are set to small and the sub is set to lfe mode. So I am wondering if this is an issue with the sub's amp and if something might need to be replaced where I am getting some bass out of it but I feel like it is not even close to what this sub should be capable of producing? Also, it shouldn't matter what input I am on right? For instance, my cable box is connected to input 1 which is labeled "vdp". Will I see any difference in bass output if I change to another input (dvd or vcr for example)?
 
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TheWarrior

TheWarrior

Audioholic Ninja
Where were those subs positioned relative to each other when you compared them?

Bass frequencies have very large wavelengths; 20 hz = 56.5 feet in diameter. This means that you are reproducing frequencies that are larger than the boundaries of your room so you will have measurable nulls where pressures at a minimum and certain bass frequencies are absent. That is not a problem with the subwoofer, but of it's location.
 
J

josh logan

Audiophyte
When I compared the subs they were right next to each other. I have tried some other places in the room for the sub but there is no improvement. I have placed it in a corner as well and found the bass did not improve either. If there was something wrong with the sub's amp would it still produce some bass as it currently is or would it not produce any sound at all?
 
lovinthehd

lovinthehd

Audioholic Jedi
If you turn the "volume" (usually called a gain adjustment) up more than half-way on the KEF does it start to work well? If you need to you can turn that up to full, it's just an adjustment to match the output of your avr's pre-out to the sub amp's sensitivity....

Re-read that, seems you have the level up full on the sub. Did you run Audyssey?

pps Looked at the 3805, it seems to not have Audyssey but another type of room eq/setup program....
 
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J

josh logan

Audiophyte
The sub does perform better as the volume increases but even with it maxed the bass is not very loud. I have no run audyssey as I don't believe it is compatible with my avr. I do have a Denon mic coming and will try the auto setup and see if that improves anything, but I don't see how it will given that all the sub settings are up all the way already.
 
lovinthehd

lovinthehd

Audioholic Jedi
Could also be the sub amp's on the way out...is this a new-to-you sub? Did it work better recently or with different gear? It's a 15 year old model it seems....
 
J

josh logan

Audiophyte
It is a new to me sub that is 12 years old according to the sticker on the bottom, lol. It was used by my grandparents so I suspect it wasn't heavily pushed. Would this be something an electronics repair shop could troubleshoot and see if it is fixable? I just thought that if there was a problem with the amp that it would just be dead and produce no sound rather than the amount of sound it's putting out now.
 
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lovinthehd

lovinthehd

Audioholic Jedi
So your grandparents may have abused it? Do you know what avr they used it with and whether it was working fine for them last time they used it? My personal experience with sub amps that go out is some varying performance and funky noises before they quit...a repair shop might be able to test it for you but I'd keep exploring your setup for now (and try that auto setup routine to see if it makes a difference).

It could be your expectations a bit perhaps...what are you testing the sub with? Have you any way to take measurements of its output? Seems the avr has sufficient pre-out voltage for the Yamaha you tested, and Denons generally do quite well in that department, but if you don't measure it, hard to know.

How are you connecting it, with a single rca input on the sub or are you using a splitter to use both L/R inputs on the sub? If you do the latter often you can gain 6dB....worth a try.
 
J

josh logan

Audiophyte
Sorry, should have read that I doubt it wasn't heavily pushed, lol. They had it hooked up to the Denon 3805 as well and they said it was working fine for them but I think they didn't really notice or care about the sub. It's not making any strange noises, doesn't even hum at all. I'm testing the sub with different things, music, movies (saving private ryan, matrix, john wick etc etc) and the Yamaha blew it out of the water. I have it connected with a y splitter coming out from the avr and using both the l/r inputs on the sub.
 
bread29

bread29

Junior Audioholic
I'm not familiar with that sub, but I don't believe you're supposed to plug into both inputs on a sub. I have an Hsu sub and only plug one wire into the white channel (L). This may be your issue?
 
J

josh logan

Audiophyte
I have tried only plugging a sub wire into each of the L/R ports and the sound is even weaker. Having the rca cable plugged into both ports gives it the louder sound.
 
William Lemmerhirt

William Lemmerhirt

Audioholic Overlord
I'm not familiar with that sub, but I don't believe you're supposed to plug into both inputs on a sub. I have an Hsu sub and only plug one wire into the white channel (L). This may be your issue?
Depends on the sub. Some models use one of the L/R for the dedicated LFE input in which case you’d use the XO in the avr. Even if you do use both(when One is not dedicated lfe) it just raises the input sensitivity and as HD said can be a workaround. Sometimes. Due to its age and design, I doubt the OP’s sub is goin to have an LFE input. The only spec I could find showed that it’s lower FR was at 30hz. My guess is that this subwoofer was designed with modest musical output in mind, while his friends Yamaha had more contemporary playback goals.(output and extension for movies and music) I know it was free, but I would definitely go shopping for a new one.
 
lovinthehd

lovinthehd

Audioholic Jedi
I'm not familiar with that sub, but I don't believe you're supposed to plug into both inputs on a sub. I have an Hsu sub and only plug one wire into the white channel (L). This may be your issue?
Sure you can use both, as I posted before and William explains (and OP confirms was his better signal level). Also if you have older gear and just L/R pre-outs you can use the L/R inputs on the sub to sum the signal to mono. It also gives generally a 6dB sensitivity/gain advantage.
 

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