Please Help: Subwoofer not responding

[jug_head26]

Hello All,

Just bought my first home theater (CP25: HK235 Receiver/DVD 22CP/HKTS7 Speakers) two months ago. Did the setup as per manual's instruction and it was working just fine.

Two weeks ago, I noticed that I’m not getting any sound from the sub. Tried doing the test tone and confirmed that the sub is not responding. I performed a processor reset but did not solve the problem.

Current Speaker Setup:
Speakers = small (front ,center and rear)
Subwoofer = SUB
Sub Volume set to 0dB or higher

X-Over:
Front, center, surround, surround back = 100HZ
LFE = Left/Right
Bass = Independent

DVD is connected using both analog (red/white) and digital (coaxial). I also noticed that the led indicator in the sub is always yellow (standby mode) when set to auto.

I’m getting sound from the sub when using the Line Level In: L.

Would appreciate any ideas and suggestions. Thanks in advance!

 

[MACCA350]

Sounds like the receiver isn't sending a signal to the sub, double check your settings with the manual because this 'LFE = Left/Right' looks like it's sending all bass to the mains.

cheers

 

[Kai]

Have you checked the hard connection, power cord and fuse on the sub?

 

[MikeSp]

Look into your bass management in the setup of your receiver -- it may be necessary to set your speakers as small in order to force the LFE to the dedicated sub (or make some other adjustment in the setup)

MikeSp

 

[jug_head26]

MACCA350: That's also my guess, just need to put the correct seeting, i've already toggled majority of the settings but to no avail.

Kai: Yes, done that and they're working fine.

MikeSp: speakers are all set to small. also tried setting them to large, still nothing.

Do i need to turn off the unit for every change i make in the setting? seems like the sub is not getting any signal from the receiver, the led is always yellow.

Also tried setting this Music-Sense to ON (to turn the led to blue), still no sound from sub.

Help!!!

 

[mtrycrafts]

Hello All,

Just bought my first home theater (CP25: HK235 Receiver/DVD 22CP/HKTS7 Speakers) two months ago. Did the setup as per manual's instruction and it was working just fine.

Two weeks ago, I noticed that I’m not getting any sound from the sub. Tried doing the test tone and confirmed that the sub is not responding. I performed a processor reset but did not solve the problem.

Current Speaker Setup:
Speakers = small (front ,center and rear)
Subwoofer = SUB
Sub Volume set to 0dB or higher

X-Over:
Front, center, surround, surround back = 100HZ
LFE = Left/Right
Bass = Independent

DVD is connected using both analog (red/white) and digital (coaxial). I also noticed that the led indicator in the sub is always yellow (standby mode) when set to auto.

I’m getting sound from the sub when using the Line Level In: L.

Would appreciate any ideas and suggestions. Thanks in advance!

How is the sub connected? When you hook up to the Left line level, what do you mean you get sound from the sub? A brief noise or the program material?

Maybe your sub needs both left and right input to it? In that case you need one of those short Y splitters into the sub.

 

[MDS]

If the 'standby' light is always illuminated and never turns green to indicate 'on', I would assume that the sub is not getting a strong enough signal to trip the auto-on feature of the sub (assuming all other settings are correct).

In general, I have found that you need to have the receiver's sub level at greater than or equal to zero, but the level of the volume control on the sub itself may be too low. When you calibrate the level of the sub, both the receiver's sub channel trim as well as the sub's volume control affects the volume. I would start with the receiver at 0 and turn up the sub volume a bit and see if things improve. If the sub has both an L and R input, you could try a Y adapter to split the single LFE out from the receiver to feed both the L and R inputs of the sub - doing so doubles the voltage fed to the sub and sometimes helps to make the auto-on feature behave more consistently.

Other settings to check:
- Many subs have a switch or require a specific input to bypass the sub's own internal xover. If you want to use the receiver for bass management (preferred), ideally you want to disable the sub's internal xover. You'll have to check the sub manual to find out if you do that by flipping a switch or using a specific input on the sub. If you cannot disable the internal xover, set it as high as it will go.

- Make sure the receiver's digital inputs are assigned correctly so that you are using the digital input from the dvd player and not the analog inputs.

- Check the dvd player settings to ensure it is set to 'bitstream' (sometimes called 'raw') mode so that the player simply sends the digital bitstream and does not decode or downmix the DD/DTS from the disc.

The LFE=Left/Right also sounds suspicious to me as well (mentioned by MACCA350). To me, that settings sounds like the feature commonly known as 'double bass' (Onkyo), LFE+MAIN or Both (Yamaha), or 'plus' (Pioneer) and will send the bass to the Large speakers, not the sub. Are there any other choices for that setting?

If all the settings seem correct, then the problem is certainly that the sub signal isn't strong enough to bring the sub out of stand-by mode and by messing with the receiver's sub level and the volume control on the sub you should be able to get it working properly.

 

[muncybob]

MDS...why is it ideal to bypass the sub's crossover and use the receiver x-over?

 

[MDS]

MDS...why is it ideal to bypass the sub's crossover and use the receiver x-over?

More options and more flexibility. Setting the xover is just one of the functions of bass management in addition to setting the speaker distances (delay time) and the Large vs Small setting to determine which speakers get which part of the frequency. Plus you can make on the fly adustments if you desire to the level and xover without having to physcially move the knobs on the subwoofer.

Using the sub's controls can work well too, but since the receiver is the brains of the system, why not let it do everything?

 

[jug_head26]

mtrycrafts: The connection is via line-level in: SUB. I do get sound from the program material when connection is via line-level in: L and R. However, I understand that you use the line-level in: SUB to get the best output from the sub, that's why I want to make it work and also know if I have a deffective unit.

MDS: Thank you for the clear explanation. And please see my reply in blue. Note that all testing done, connection is via line-level in: SUB.

MDS wrote:
If the 'standby' light is always illuminated and never turns green to indicate 'on', I would assume that the sub is not getting a strong enough signal to trip the auto-on feature of the sub (assuming all other settings are correct).

In general, I have found that you need to have the receiver's sub level at greater than or equal to zero, but the level of the volume control on the sub itself may be too low. When you calibrate the level of the sub, both the receiver's sub channel trim as well as the sub's volume control affects the volume. I would start with the receiver at 0 and turn up the sub volume a bit and see if things improve. If the sub has both an L and R input, you could try a Y adapter to split the single LFE out from the receiver to feed both the L and R inputs of the sub - doing so doubles the voltage fed to the sub and sometimes helps to make the auto-on feature behave more consistently.

Tried playing with the receiver's sub level and subwoofer's volume - zero sound.

Other settings to check:
- Many subs have a switch or require a specific input to bypass the sub's own internal xover. If you want to use the receiver for bass management (preferred), ideally you want to disable the sub's internal xover. You'll have to check the sub manual to find out if you do that by flipping a switch or using a specific input on the sub. If you cannot disable the internal xover, set it as high as it will go.

Using the line-level in: SUB bypasses the sub's internal crossover circuitry. This is also one of the reason why I prefer using this connection instead of the line-level in: L and R.

- Make sure the receiver's digital inputs are assigned correctly so that you are using the digital input from the dvd player and not the analog inputs.

DVD's input is COAX1.

- Check the dvd player settings to ensure it is set to 'bitstream' (sometimes called 'raw') mode so that the player simply sends the digital bitstream and does not decode or downmix the DD/DTS from the disc.

DVD is always set to bitstream.

The LFE=Left/Right also sounds suspicious to me as well (mentioned by MACCA350). To me, that settings sounds like the feature commonly known as 'double bass' (Onkyo), LFE+MAIN or Both (Yamaha), or 'plus' (Pioneer) and will send the bass to the Large speakers, not the sub. Are there any other choices for that setting?

This what confuses me. For x-over setup, the manual shows SUBWOOFER: LEFT/RIGHT, my receiver displays LFE: LEFT/RIGHT. Can this be causing the problem???

If all the settings seem correct, then the problem is certainly that the sub signal isn't strong enough to bring the sub out of stand-by mode and by messing with the receiver's sub level and the volume control on the sub you should be able to get it working properly.

 

[jug_head26]

One more thing, when doing the test tone, sub doesn't make any sound.

 

[MDS]

One more thing, when doing the test tone, sub doesn't make any sound.

Then the receiver must think that there is no sub. I still think that the sub=left/right setting is the culprit. Most receivers simply have yes or no options for the sub and if set to No, the LFE goes to the left and right speakers. It sounds like you have it set to do just that. Is there another option you can set it to, like Yes or On?

 

[jug_head26]

MDS: I guess you're right. The receiver may not be detecting the subwoofer. Below are the options available for the speaker setup. Tried already all possible combination but still no luck.

Mode: Size
Left/Right: Small Large
Center: Small Small
Surround: Small Small
Surr Back: Small Small
Subwoofer: Sub L/R+LFE, LFE, None
Bass Mgr: Independent, Global Independent

Mode: X-Over
Left/Right: 100HZ
Center: 100HZ
Surround: 100HZ
Surr Back: 100HZ
LFE: Left/Right, Center, Surround, Surr Back
Bass Mgr: Independent, Global

Anything else we can try?

 

[jug_head26]

Let me repeat that.
What I'm trying to say is that when Left/Right is set to Large, new options for Subwoofer becomes available.

Mode: Size
Left/Right: Small
Center: Small
Surround: Small
Surr Back: Small
Subwoofer: Sub
Bass Mgr: Independent, Global

Left/Right: Large
Center: Small
Surround: Small
Surr Back: Small
Subwoofer: L/R+LFE, LFE, None
Bass Mgr: Independent, Global


Mode: X-Over (Same for both: Small and Large)
Left/Right: 100HZ
Center: 100HZ
Surround: 100HZ
Surr Back: 100HZ
LFE: Left/Right, Center, Surround, Surr Back
Bass Mgr: Independent, Global

 

[mfabien]

Let me repeat that.
What I'm trying to say is that when Left/Right is set to Large, new options for Subwoofer becomes available.

Mode: Size
Left/Right: Small
Center: Small
Surround: Small
Surr Back: Small
Subwoofer: Sub
Bass Mgr: Independent, Global

Left/Right: Large
Center: Small
Surround: Small
Surr Back: Small
Subwoofer: L/R+LFE, LFE, None
Bass Mgr: Independent, Global


Mode: X-Over (Same for both: Small and Large)
Left/Right: 100HZ
Center: 100HZ
Surround: 100HZ
Surr Back: 100HZ
LFE: Left/Right, Center, Surround, Surr Back
Bass Mgr: Independent, Global

I would have all speakers set to SMALL. For Subwoofer, I would select only LFE.

For Crossover, I would also try 90 Hz and 80 Hz and play a CD or something at all 3 settings then decide which is best.

 

[MDS]

Let me repeat that.
What I'm trying to say is that when Left/Right is set to Large, new options for Subwoofer becomes available.

Mode: Size
Left/Right: Small
Center: Small
Surround: Small
Surr Back: Small
Subwoofer: Sub
Bass Mgr: Independent, Global

Left/Right: Large
Center: Small
Surround: Small
Surr Back: Small
Subwoofer: L/R+LFE, LFE, None
Bass Mgr: Independent, Global


Mode: X-Over (Same for both: Small and Large)
Left/Right: 100HZ
Center: 100HZ
Surround: 100HZ
Surr Back: 100HZ
LFE: Left/Right, Center, Surround, Surr Back
Bass Mgr: Independent, Global

You want the first block of settings with every channel set to Small and the Subwoofer set to Sub. Bass below the xover frequency for all Small channels should go to the sub and LFE will always go to the sub. Because you have the xover set to the same value for every channel, it shouldn't matter whether Bass Mgr is set to Independent or Global - Global would mean the same xover is used for each channel whereas independent would allow you to set different xovers for each channel. 'Global' is the norm for most receivers.

The 'LFE' setting under xover makes no sense to me. That option should not be available unless you set the fronts to Large and make the other subwoofer options available. Normally, when you have the mains set to Large with no subwoofer LFE goes to those mains. I'm guessing this LFE setting is to give you the flexibility of directing it to any other speakers rather than the mains, which in my opinion is useless.

What receiver make and model? I'd like to read the manual for it.

 

[Nick250]

How about the make an model of the sub too. Yes?

 

[jug_head26]

CP25: HK235 Receiver/HK DVD 22CP/HKTS7 Speakers