KLH Subwoofer connection

[meranaamjoker]

Trying to figure out how to connect a KLH GFX550 sub to my Teac receiver

From the look of it, the sub seems to have two ways to receive signal from the receiver.

1) Low level input - R & L on the back of the sub. In the receiver only one output for pre-amp subwoofer out.

I tried using a video composite cable (two male pins on both sides). On the woofer side I connected two male pins and on the receiver side I connected one of the two pins into the pre-amp sub out. I get pretty weak bass with the sub woofer's frequency and gain turned half way. If I up the frequency and gain there is decent amount of bass

2) Speaker wire input: I connected speaker wire to the "B" side of the receiver and also to the back of the woofer. The signal is better, but my receive can't play A&B together, so this solution won't work for me. A side has a common center, Rear R&L speakers and Side R&L speakers. This connection did seem to have better bass than #1 above, with gain turned to about 65-70% and frequency turned to about 100Hz.

3) I devised another way to connect. I simply connected the sub woofer speaker wires to into the same slots that the A side front right speakers are connected to, so essentially, the two slots for the front speaker are feeding both right front as well as the sub. This seems to work with the same level of result as #2 above.

Question:

A - Ideally I would like to make #1 above work with good result, am I using the wrong cable or is this a problem with the sub? I bought the sub on craigslist. What's a Low level input?

B - Is there a problem if I continue with #3 above? Any risks or dangers?

 

[j_garcia]

Use the preamp subwoofer out to the L&R inputs on the sub using an RCA cable. You can connect it to one or the other of the R & L inputs as they both sum to the same signal internally in the sub. This method will give better results sound wise than using the speaker wire. No danger in doing it the way you have it, but it also will not play back the LFE channel in multichannel audio.

 

[meranaamjoker]

Thanks for the reply. What you suggest is essentially what I did in connection option #1, with the difference being I used video composite cables instead of RCA. This didn't produce strong bass, like the speaker wire does. So would the sound get better if I use RCA? I have heard for this purpose both composite and RCA product equal results.

 

[everettT]

Thanks for the reply. What you suggest is essentially what I did in connection option #1, with the difference being I used video composite cables instead of RCA. This didn't produce strong bass, like the speaker wire does. So would the sound get better if I use RCA? I have heard for this purpose both composite and RCA product equal results.

All rca cables at short runs are all the same no matter the sleeve color

 

[WaynePflughaupt]

What you’re referring to as video composite cables and RCA cables are the same thing. For this purpose, only the color of the plastic plug cover is different.

Thanks for the reply. What you suggest is essentially what I did in connection option #1, with the difference being I used video composite cables instead of RCA. This didn't produce strong bass, like the speaker wire does. So would the sound get better if I use RCA? I have heard for this purpose both composite and RCA product equal results.

You’re confusing signal gain with sound quality. The speaker wire is merely getting a hotter input signal to the sub (that’s why the RCA input jacks are labeled “low level”). That has nothing to do with sound quality.
You said you got weak bass using the video cable with the gain knob half-way up, but decent bass with it turned up higher. So, turn it up. That’s what it’s there for, to be adjusted as needed.

As far as the crossover (“frequency”) setting, your TEAC receiver should be handling that. If it doesn’t, then the frequency knob on the sub should be adjusted to the frequency that your main speakers start rolling out.

Regards,
Wayne A. Pflughaupt

 

[snakeeyes]

That is a pretty pedestrian sub to be honest. Do you have budget to replace it? A sub from HSU or Rythmik or SVS or Monolith would be a huge upgrade.

 

[j_garcia]

Thanks for the reply. What you suggest is essentially what I did in connection option #1, with the difference being I used video composite cables instead of RCA. This didn't produce strong bass, like the speaker wire does. So would the sound get better if I use RCA? I have heard for this purpose both composite and RCA product equal results.

You have to adjust the sub's output in the receiver too, not just at the sub. Should be able to get similar results in output via this method. Where you will notice it most is with tracks that have the ".1" LFE channel, such as most movies. Yes, composite video and analog cables should effectively be interchangeable.

 

[lovinthehd]

What model Teac avr?

 

[meranaamjoker]

What model Teac avr?

It's a TEAC V8525

 

[lovinthehd]

It's a TEAC V8525

Don't see a manual for that as to whether it has a full range sub pre-out or not (so as to set the low pass filter on the sub appropriately as Wayne mentioned for determining best crossover for your speakers).