Passive Subwoofer With Stereo Power Amp

  • Thread starter Rodney Blanchard
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Rodney Blanchard

Audiophyte
I have searched the forum and have not found this answer any where. I have a passive in-wall subwoofer that I would like to power with a Parasound Quatro Amp. The amp is a stereo multi zone amp that is 90watts at 4ohms (sub is 4ohms). Plenty for this sub.

I plug the subwoofer out of my brand new Denon X1200. I get nothing on the sub when plug into the subwoofer output. The woofer does play if plug in a stereo source so I know it is not the amp or wiring. I am sure it has to do with incompatibility between subwoofer out and stereo input. Can someone point me in the right direction? Finding this on the Internet is a series of empty rabbit holes. Thanks
 
M

markw

Audioholic Overlord
When you say it only plays in stereo, are you saying that it doesn't play when another source requires it?

Subs don't play constantly in movies, only occasionally. ...just a stab in the dark here.
 
R

Rodney Blanchard

Audiophyte
When you say it only plays in stereo, are you saying that it doesn't play when another source requires it?

Subs don't play constantly in movies, only occasionally. ...just a stab in the dark here.
I am using the subwoofer test tone from the Denon just to generate sound. I get nothing. But I do get sound when I plug in a iTouch to the same port on the amp.
 
TLS Guy

TLS Guy

Seriously, I have no life.
I am using the subwoofer test tone from the Denon just to generate sound. I get nothing. But I do get sound when I plug in a iTouch to the same port on the amp.
In the speaker set up menu on the Denon, have you selected yes, to the subwoofer? If you have told the Denon you have a sub, and you can't get the subwoofer to play the test tone, then the Denon is defective.

If you can't get the test tone to play, do a factory reset back to default and re set up. If you don't get the test tone then, the Denon needs repair or replacement.
 
R

Rodney Blanchard

Audiophyte
In the speaker set up menu on the Denon, have you selected yes, to the subwoofer? If you have told the Denon you have a sub, and you can't get the subwoofer to play the test tone, then the Denon is defective.

If you can't get the test tone to play, do a factory reset back to default and re set up. If you don't get the test tone then, the Denon needs repair or replacement.
I have plugged the Denon into a powered sub and it works.
 
M

markw

Audioholic Overlord
It sounds like you've pretty much isolated the problem to the Parasound amp. check your connections, then I'm out of ideas.
 
TLS Guy

TLS Guy

Seriously, I have no life.
I have plugged the Denon into a powered sub and it works.
How do you have the two units connected?

You can only use one channel of the Parasound.

I see that unit has an auto on feature. It has two sensitivity settings. You need to select the lowest MV, which is the highest sensitivity. Even then, it might not work. I do not see this auto on as able to be defeated. The power output from a sub is usually very low.

One channel only has 50 watts output from the Parasound.

That amp does not look like a good unit for driving a sub and may well not be suitable.
 
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highfigh

highfigh

Seriously, I have no life.
I have searched the forum and have not found this answer any where. I have a passive in-wall subwoofer that I would like to power with a Parasound Quatro Amp. The amp is a stereo multi zone amp that is 90watts at 4ohms (sub is 4ohms). Plenty for this sub.

I plug the subwoofer out of my brand new Denon X1200. I get nothing on the sub when plug into the subwoofer output. The woofer does play if plug in a stereo source so I know it is not the amp or wiring. I am sure it has to do with incompatibility between subwoofer out and stereo input. Can someone point me in the right direction? Finding this on the Internet is a series of empty rabbit holes. Thanks
How do you have the two units connected?

You can only use one channel of the Parasound.

I see that unit has an auto on feature. It has two sensitivity settings. You need to select the lowest. Even then, it might not work. I do not see this auto on as able to be defeated. The power output from a sub is usually very low.

One channel only has 50 watts output from the Parasound.

That amp does not look like a good unit for driving a sub and may well not be suitable.
The switch for the amp's auto on also has a position for 12VDC trigger and Manual operation, so that's really not the issue. The high sensitivity position should be used, BTW- if the music has extremely quiet passages, it could turn off when the sensitivity is too low.

The real problem is that the amp can't be operated in bridge/Mono mode and it's not designed for powering subwoofers- it's made for people who want a smaller system, but don't want bad performance.
 
R

Rodney Blanchard

Audiophyte
The switch for the amp's auto on also has a position for 12VDC trigger and Manual operation, so that's really not the issue. The high sensitivity position should be used, BTW- if the music has extremely quiet passages, it could turn off when the sensitivity is too low.

The real problem is that the amp can't be operated in bridge/Mono mode and it's not designed for powering subwoofers- it's made for people who want a smaller system, but don't want bad performance.
I have the amp set so that the amp is on when the power button on the front is pushed it is on. There are three settings, auto, 12 volt and power. So you are saying that if an amp bridgeable(mono) it can handle LFE output? Regardless of the power level of the amp, I should get something right?
 
M

markw

Audioholic Overlord
So you are saying that if an amp bridgeable(mono) it can handle LFE output? Regardless of the power level of the amp, I should get something right?
No, that's not what he said. Besides, you cannot bridge that amp.

My $$ is on that you have that amp set for "auto" and the LFE signal isn't strong enough to trigger the amp. Remember, this unit is designed to work with a preamp output, not a LFE output.

Reread this post. The guy usually knows what he's talking about.
I see that unit has an auto on feature. It has two sensitivity settings. You need to select the lowest MV, which is the highest sensitivity. Even then, it might not work. I do not see this auto on as able to be defeated. The power output from a sub is usually very low.
 
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R

Rodney Blanchard

Audiophyte
No, that's not what he said. Besides, you cannot bridge that amp.

My $$ is on that you have that amp set for "auto" and the LFE signal isn't strong enough to trigger the amp. Remember, this unit is designed to work with a preamp output, not a LFE output.

Reread this post. The guy usually knows what he's talking about.
I greatly appreciate all your input. The amp is set to manual which bypasses the audio sensitivity bits. I am using the test tone for the sub output on the Denon and ramped up the level fairly high with no joy.

I am very aware that you cannot bridge the amp, I thought what he was saying that this will only work on amp that can be bridged. I must have misunderstood what he was saying.

Some background on why I am trying to use this amp is in this way may be useful. I have very limited rack space and am attempting to put 4 in-wall subs in for 4 different surround rooms. They are not heavy listening rooms so having mega power is not a real issue. I am using 4 ohm subs so this amp at 4 ohms is rated at 90 watts. The Parasound amps tend to play louder than rated so I am not really worried about power that much. Right now I am just trying to get the test sub to play some kind of sound. I was thinking it might be a crossover mismatch issue or a something that is not readily evident. I am at a loss to understand why I cannot get any sound when connecting to the sub output.

Any ideas or suggestions would be greatly appreciated. Thank you
 
P

PENG

Audioholic Slumlord
I greatly appreciate all your input. The amp is set to manual which bypasses the audio sensitivity bits. I am using the test tone for the sub output on the Denon and ramped up the level fairly high with no joy.

I am very aware that you cannot bridge the amp, I thought what he was saying that this will only work on amp that can be bridged. I must have misunderstood what he was saying.

Some background on why I am trying to use this amp is in this way may be useful. I have very limited rack space and am attempting to put 4 in-wall subs in for 4 different surround rooms. They are not heavy listening rooms so having mega power is not a real issue. I am using 4 ohm subs so this amp at 4 ohms is rated at 90 watts. The Parasound amps tend to play louder than rated so I am not really worried about power that much. Right now I am just trying to get the test sub to play some kind of sound. I was thinking it might be a crossover mismatch issue or a something that is not readily evident. I am at a loss to understand why I cannot get any sound when connecting to the sub output.

Any ideas or suggestions would be greatly appreciated. Thank you
If it works with a powered sub it should work with the passive sub via a power amp. You did say it worked with a powered sub right? Do you know the model number of the passive sub?
 
R

Rodney Blanchard

Audiophyte
If it works with a powered sub it should work with the passive sub via a power amp. You did say it worked with a powered sub right? Do you know the model number of the passive sub?
Yes, it does work with the powered sub. Yes, I agree, it should work. This is very weird.
 
P

PENG

Audioholic Slumlord
Yes, it does work with the powered sub. Yes, I agree, it should work. This is very weird.
You can try using zone2 for the external amp, make sure it is set to variable gain. Actually you better read the manual about how to use zone2 before doing any experiment. Again, a model number of the passive subwoofer will help us troubleshoot too. Are you sure the sub is actually working anyway?
 
P

PENG

Audioholic Slumlord
No, that's not what he said. Besides, you cannot bridge that amp.

My $$ is on that you have that amp set for "auto" and the LFE signal isn't strong enough to trigger the amp. Remember, this unit is designed to work with a preamp output, not a LFE output.
According to the manual, his amp has a pretty good sensitivity:

"Input Sensitivity: 700mv = Full output (50 Watts @ 8 Ω) Total Gain = 29 dB (Level controls set to Maximum)"

However, I see your point, that's why I am suggesting he tried the zone2 output as well and go from there. Apparently the X1200W zone2 works with any selected input source but I think one needs to read the fine prints in the manual regardless.
 
R

Rodney Blanchard

Audiophyte
Peng, thank you for your input.

I did use the output from another device directly into the Zamp and was able to get sound from the speaker through the Zamp. I assume that is what you are suggesting by using the zone 2 out of the receiver. I need/want the to connect the passive sub to sub out on the receiver.

The test speaker is a cheep in-wall I had laying round (not really relevant). I did hook it to a functioning 12" passive sub in a RBH 1266-SE tower speaker. That did not work either. Again at this point I am just trying to get some kind of sound. All I am currently getting is the short hum when you first plug the sub out to the Zamp channel 1 input. It is the hum you normally get when plugging in a powered up powered subwoofer.

I have done this before with of stereo amps and it has worked. When you say read the finer print is there something in the manual that raised a red flag for you? I did not see anything.
 
M

markw

Audioholic Overlord
All I am currently getting is the short hum when you first plug the sub out to the Zamp channel 1 input. It is the hum you normally get when plugging in a powered up powered subwoofer.
It's good practice to have everything powered off when kerfutzing with connections, either interconnects or speaker cables. It's cheap insurance.

As for your main problem, perhaps Parasound could offer some input. After all, if the LFE drives a power sub (which is it's intended purpose) but not the Parasound, the problem obviously lies there
 
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highfigh

highfigh

Seriously, I have no life.
Con
I greatly appreciate all your input. The amp is set to manual which bypasses the audio sensitivity bits. I am using the test tone for the sub output on the Denon and ramped up the level fairly high with no joy.

I am very aware that you cannot bridge the amp, I thought what he was saying that this will only work on amp that can be bridged. I must have misunderstood what he was saying.

Some background on why I am trying to use this amp is in this way may be useful. I have very limited rack space and am attempting to put 4 in-wall subs in for 4 different surround rooms. They are not heavy listening rooms so having mega power is not a real issue. I am using 4 ohm subs so this amp at 4 ohms is rated at 90 watts. The Parasound amps tend to play louder than rated so I am not really worried about power that much. Right now I am just trying to get the test sub to play some kind of sound. I was thinking it might be a crossover mismatch issue or a something that is not readily evident. I am at a loss to understand why I cannot get any sound when connecting to the sub output.

Any ideas or suggestions would be greatly appreciated. Thank you
Connect anything else to the ZQuattro's input jack of the channel your sub is connected to. iPod, Walkman, Preamp out, signal generator- it shouldn't matter, you should have sound. If you hear something with stereo input, and I'm not trying to be condescending, make sure the level control and input being used are for the channel that's connected to the sub- it happens all the time.

Try a different cable, check the end and make sure it's not damaged or loose. If you plugged the cable into the AVR by feeling around for where you think the Sub Out jack is, verify that you're using the correct one- Denon and most other manufacturers use white or gray cross-hatching to designate the output jacks and if you connected to Sub Out 2 without assigning it, it won't provide sound.
 
P

PENG

Audioholic Slumlord
I did use the output from another device directly into the Zamp and was able to get sound from the speaker through the Zamp. I assume that is what you are suggesting by using the zone 2 out of the receiver. I need/want the to connect the passive sub to sub out on the receiver.
I suggested using the zone2 on the Denon because if that works then the Parasound amp is not the problem.

It is the hum you normally get when plugging in a powered up powered subwoofer.
Be careful, see post#17.

I have done this before with of stereo amps and it has worked. When you say read the finer print is there something in the manual that raised a red flag for you? I did not see anything.
No, I simply meant if you were to try the Denon's zone2 output then you should read the manual first because it is not as straight forward as using the main zone, but the X7200W does not have preouts for the main zone.

Did you double check to make sure the channel level controls (see page 9 of the Quattro's manual) are set to maximum? The thing is, by using just the subwoofer test tone you have eliminated several possible causes.

To summarize, make sure you check the following:

1) Set “Speaker Config.” – “Subwoofer” on the menu to “Yes”. See Denon manual page 188.
2) Set to Subwoofer "On". See Denon manual page 155.
3) Set Subwoofer Mode to "LFE+Main", (just for troubleshooting), see page 195.
4) Set Subwoofer Mode to LPE for LFE 250 Hz (again, just for troubleshooting), see page 195.
5) Set Subwoofer level to "0" (default), or higher such as +6 (also just for troubleshooting), see page 151.

6) Connect Denon's subout (either one of the two) to the Parasound Quattro's zone 1 channel 1 (obviously can be any of the 4).
7) Turn the channel level control knob for channel 1 (or whichever one you are using) fully clockwise for maximum volume. To be bullet proof, you can turn all 4 knobs to maximum.
8) Connect your passive sub to the Quattro's channel 1 (left) speaker ouput, or any other channel that you have the input connected to the Denon's subout.

As you know already, some of the above steps are redundant if you are using the subwoofer level test tone but it won't hurt to do them either.
 
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