Harman Kardon HK990 subwoofer outputs?

pieskapov · 4th March 2012, 11:40 AM

Hi there specialists,

I look harman/kardon HK990 amplifier and there are two subwoofer output. In the back panel there are “SUB 1” and “SUB 2”. But in the real life, both of those outputs give mono-signal.

In the schematic diagram, there is marked “Subwoofer OUT L” and “Subwoofer OUT R”. And it looks like those connectors are in stereo.

Have you any idea, why those subwoofer outputs are mono?
Is it made by software or hardware?

Thanks!

Kal Rubinson · 4th March 2012, 03:24 PM

AFAIK, they are stereo outputs if you feed the 990 with stereo sub inputs but can be stereo or mono if you have the 990 derive the sub outputs. Have you checked the user's manual about this?

Kal

SoNic_real_one · 4th March 2012, 03:50 PM

Some active subwoofers have two line inputs (L and R) and filter/join those inside. This is applicable to stereo programs.
The "mono" subwoofer is actually a LFE channel applicable for 5.1/7.1 programs (Dolby Digital/ DTS... etc).
I am sure that in the manual is described a setting to use just one of thse outputs (to be joined in the receiver) for stereo programs. For 5.1 programs probably both have the same signal, so you can use only one.

pieskapov · 10:23 PM

Quote:

Originally Posted by Kal Rubinson

AFAIK, they are stereo outputs if you feed the 990 with stereo sub inputs but can be stereo or mono if you have the 990 derive the sub outputs. Have you checked the user's manual about this?

Kal

Hi!

If I try with test-cd, both of those sub outputs gives the signal even if signal from disc is only one channel.
Thats really weird...
In the manual there is only "Output jacks for two subwoofers".

/vesa

Kal Rubinson · 5th March 2012, 02:56 PM

I was thinking of the direct analog input but my memory is hazy.

SoNic_real_one · 04:16 PM

Quote:

Originally Posted by pieskapov

Hi!
If I try with test-cd, both of those sub outputs gives the signal even if signal from disc is only one channel.
Thats really weird...

That's not weird if you have programmed any EQ mode... At crossover frequency, bass will go towards on or both subs - depending of your selection in the "speaker" menu.
See page 10, 11 of the manual.

pieskapov · 6th March 2012, 07:29 AM

Ok, when I made the test, settings were:
Speaker setup: Manual
SUB1: ON
SUB2: ON
CROSSOVER FREQ: 100Hz
EzSet/EQ:OFF DSP PATH

SoNic_real_one · 6th March 2012, 02:59 PM

So, your incoming stereo signal will be pass trough DSP and the portion below 100Hz is converted to mono and send to BOTH subwoofer outputs.
The main L/R outputs will not have any low-frequency below 100Hz send to speakers.

pieskapov · 7th March 2012, 06:38 AM

Well, actually what I need is high pass filter (>100Hz) to main speaker AND two channel (stereo) full band output to active crossover/eq of subwoofers
OR
high pass filter (>100Hz) to main speaker AND two channel (stereo) low pass (<100Hz) output to eq of subwoofers.

If I use h/k high pass filter in speaker setup (40-200Hz) in manual mode, after that also preamplifier output jack gives high pass signal.
So, from where I get full pass stereo signal to sub if I use high pass filter to main speakers?

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4th March 2012, 03:24 PM	#2
Kal Rubinson diyAudio Member Join Date: Oct 2003 Location: NYC	AFAIK, they are stereo outputs if you feed the 990 with stereo sub inputs but can be stereo or mono if you have the 990 derive the sub outputs. Have you checked the user's manual about this? Kal

4th March 2012, 03:50 PM	#3
SoNic_real_one diyAudio Member Join Date: Jan 2008 Location: Virginia	Some active subwoofers have two line inputs (L and R) and filter/join those inside. This is applicable to stereo programs. The "mono" subwoofer is actually a LFE channel applicable for 5.1/7.1 programs (Dolby Digital/ DTS... etc). I am sure that in the manual is described a setting to use just one of thse outputs (to be joined in the receiver) for stereo programs. For 5.1 programs probably both have the same signal, so you can use only one.

5th March 2012, 02:56 PM	#5
Kal Rubinson diyAudio Member Join Date: Oct 2003 Location: NYC	I was thinking of the direct analog input but my memory is hazy.

6th March 2012, 07:29 AM	#7
pieskapov diyAudio Member Join Date: Nov 2009	Ok, when I made the test, settings were: Speaker setup: Manual SUB1: ON SUB2: ON CROSSOVER FREQ: 100Hz EzSet/EQ:OFF DSP PATH

6th March 2012, 02:59 PM	#8
SoNic_real_one diyAudio Member Join Date: Jan 2008 Location: Virginia	So, your incoming stereo signal will be pass trough DSP and the portion below 100Hz is converted to mono and send to BOTH subwoofer outputs. The main L/R outputs will not have any low-frequency below 100Hz send to speakers.

7th March 2012, 06:38 AM	#9
pieskapov diyAudio Member Join Date: Nov 2009	Well, actually what I need is high pass filter (>100Hz) to main speaker AND two channel (stereo) full band output to active crossover/eq of subwoofers OR high pass filter (>100Hz) to main speaker AND two channel (stereo) low pass (<100Hz) output to eq of subwoofers. If I use h/k high pass filter in speaker setup (40-200Hz) in manual mode, after that also preamplifier output jack gives high pass signal. So, from where I get full pass stereo signal to sub if I use high pass filter to main speakers?