How to level match two different subwoofers? - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 24 Old 02-22-2017, 06:18 AM - Thread Starter
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I see alot about gain and level matching your subwoofers for a dual sub setup, but I don't understand how to level match two different subwoofers with a receiver with only one subwoofer output.

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post #2 of 24 Old 02-22-2017, 11:18 AM
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Need more information.

What subs?
Where will they be placed?
How large is the room?

The short answer is; if you want to level match them, you use an SPL meter placed at the MLP and use the gain knobs on the back of the subs. Gain matching dissimilar subs is not recommended.
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post #3 of 24 Old 02-22-2017, 11:26 AM
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Measure.
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post #4 of 24 Old 02-22-2017, 01:11 PM - Thread Starter
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Quote:
Originally Posted by Alan P View Post
Need more information.

What subs?
Where will they be placed?
How large is the room?

The short answer is; if you want to level match them, you use an SPL meter placed at the MLP and use the gain knobs on the back of the subs. Gain matching dissimilar subs is not recommended.
Okay, well one is an XTZ 12.17 and the other is an XTZ 99 w12.16. The room is about 210 square feet with a pretty high roof, around 12 feet. I am hoping to place them along the front wall, under the front left and right speakers. Also, what is the difference between gain match and level match?

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post #5 of 24 Old 02-22-2017, 01:55 PM
 
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Originally Posted by Ultim8dude View Post
I am hoping to place them along the front wall, under the front left and right speakers.
That's usually the worst place to put subs. There are literally hundreds of threads here on that subject. After you determine where to place them for best results set their individual volumes as required.
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post #6 of 24 Old 02-22-2017, 02:19 PM - Thread Starter
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Originally Posted by Ultim8dude View Post
I am hoping to place them along the front wall, under the front left and right speakers.
That's usually the worst place to put subs. There are literally hundreds of threads here on that subject. After you determine where to place them for best results set their individual volumes as required.
Alright, my only issue is that I don't have so many placement options :/ However, i shall do the subwoofer crawl and see how it pans out. Thanks.
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post #7 of 24 Old 02-22-2017, 03:22 PM
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Quote:
Originally Posted by Ultim8dude View Post
Okay, well one is an XTZ 12.17 and the other is an XTZ 99 w12.16. The room is about 210 square feet with a pretty high roof, around 12 feet. I am hoping to place them along the front wall, under the front left and right speakers. Also, what is the difference between gain match and level match?
Gain matching; using a close-mic measurement (1"-2" from cone), adjusting each sub to output the same SPL.
Level matching; measuring from the MLP, adjusting each sub so that the SPL is the same at the MLP.

Gain matching takes the effects of the room out of the equation, level matching takes the effects of the room into consideration.

There are pros and cons to each method. If you do a search you will find a lot of discussion on the subject:

https://www.google.com/#q=gain+match...w.avsforum.com
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post #8 of 24 Old 02-22-2017, 03:51 PM - Thread Starter
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Originally Posted by Ultim8dude View Post
Okay, well one is an XTZ 12.17 and the other is an XTZ 99 w12.16. The room is about 210 square feet with a pretty high roof, around 12 feet. I am hoping to place them along the front wall, under the front left and right speakers. Also, what is the difference between gain match and level match?
Gain matching; using a close-mic measurement (1"-2" from cone), adjusting each sub to output the same SPL.
Level matching; measuring from the MLP, adjusting each sub so that the SPL is the same at the MLP.

Gain matching takes the effects of the room out of the equation, level matching takes the effects of the room into consideration.

There are pros and cons to each method. If you do a search you will find a lot of discussion on the subject:

https://www.google.com/#q=gain+match...w.avsforum.com

Okay, thanks for clearing that up I searched it but I couldn't really grasp the difference, but now it makes sense, so I'll make sure to level match them once I decide where to place them.
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post #9 of 24 Old 02-22-2017, 04:01 PM
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Originally Posted by Ultim8dude View Post
Okay, thanks for clearing that up I searched it but I couldn't really grasp the difference, but now it makes sense, so I'll make sure to level match them once I decide where to place them.
Hi,

You didn't say what kind of an AVR you have. But, if you have one with an automated calibration routine, I would probably just let the AVR match each sub separately, to the same volume, and then Y-connect them and run the calibration again. I have more faith in something like Audyssey, than I do in an uncalibrated SPL meter, particularly at subwoofer frequencies. And, you would like to start with your whole system level-matched, anyway, before you apply whatever sub boost you are going to add.

Regards,
Mike
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GUIDE TO SUBWOOFER CALIBRATION AND BASS PREFERENCES

* The Guide linked above is a comprehensive guide to Audio & HT systems, including:
Speaker placements & Room treatments; HT calibration & Room EQ; Room gain; Bass
Preferences; Subwoofer Buyer's Guide: Sealed/ported; ID subs; Subwoofer placement.
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post #10 of 24 Old 02-22-2017, 04:09 PM
 
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Originally Posted by Alan P View Post
Gain matching; using a close-mic measurement (1"-2" from cone), adjusting each sub to output the same SPL.
Level matching; measuring from the MLP, adjusting each sub so that the SPL is the same at the MLP.
There's a third method. There's no reason why the subs must provide either the same output or the same SPL at the MLP. The main purpose of multiple subs is to give the smoothest possible response at the MLP. To do so they might not have either the same output or the same SPL at the MLP. Finding what works best is a trial and error process, and requires measurement tools, but if you can do it the result may turn out much better than arbitrary gain or level matching.
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post #11 of 24 Old 02-22-2017, 04:17 PM - Thread Starter
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Originally Posted by mthomas47 View Post
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Originally Posted by Ultim8dude View Post
Okay, thanks for clearing that up I searched it but I couldn't really grasp the difference, but now it makes sense, so I'll make sure to level match them once I decide where to place them.
Hi,

You didn't say what kind of an AVR you have. But, if you have one with an automated calibration routine, I would probably just let the AVR match each sub separately, to the same volume, and then Y-connect them and run the calibration again. I have more faith in something like Audyssey, than I do in an uncalibrated SPL meter, particularly at subwoofer frequencies. And, you would like to start with your whole system level-matched, anyway, before you apply whatever sub boost you are going to add.

Regards,
Mike
Yeah I completely forgot about that. I have a 5.1 Yamaha receiver, not sure which model but it has ypao. But do you mean that I should adjust the volume knob on the subs until the ypao gives the same level to both?
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post #12 of 24 Old 02-22-2017, 05:17 PM
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Originally Posted by Ultim8dude View Post
Yeah I completely forgot about that. I have a 5.1 Yamaha receiver, not sure which model but it has ypao. But do you mean that I should adjust the volume knob on the subs until the ypao gives the same level to both?
Yes, that's right! Without serious measuring equipment, that would be my preferred method.

GUIDE TO SUBWOOFER CALIBRATION AND BASS PREFERENCES

* The Guide linked above is a comprehensive guide to Audio & HT systems, including:
Speaker placements & Room treatments; HT calibration & Room EQ; Room gain; Bass
Preferences; Subwoofer Buyer's Guide: Sealed/ported; ID subs; Subwoofer placement.
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post #13 of 24 Old 02-22-2017, 06:15 PM
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post #14 of 24 Old 02-22-2017, 06:28 PM
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Originally Posted by Bill Fitzmaurice View Post
There's a third method. There's no reason why the subs must provide either the same output or the same SPL at the MLP. The main purpose of multiple subs is to give the smoothest possible response at the MLP. To do so they might not have either the same output or the same SPL at the MLP. Finding what works best is a trial and error process, and requires measurement tools, but if you can do it the result may turn out much better than arbitrary gain or level matching.


Notwithstanding the trial and error aspect, is there a basic procedure to follow for this third approach?
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post #15 of 24 Old 02-22-2017, 08:22 PM
 
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Notwithstanding the trial and error aspect, is there a basic procedure to follow for this third approach?
I would set one sub at a moderate volume, then sweep the volume of the second sub until the charting showed the flattest response at the LP. Then I'd use the volume controls in the AVR to fine tune the sub level to the mains level. If the second sub didn't smooth the response I'd try different placements.
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post #16 of 24 Old 02-22-2017, 08:28 PM
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I would set one sub at a moderate volume, then sweep the volume of the second sub until the charting showed the flattest response at the LP. Then I'd use the volume controls in the AVR to fine tune the sub level to the mains level. If the second sub didn't smooth the response I'd try different placements.


Hmmm - this sounds like a good use for the real time analyzer in REW. Would this same basic approach be appropriate for setting relative phasing between two subs?
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post #17 of 24 Old 02-22-2017, 08:43 PM
 
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Would this same basic approach be appropriate for setting relative phasing between two subs?
You could do that. You'd also see the effect of a polarity or time/phase adjustment in the region of the crossover between the subs and mains, so that you'd want to do it with the full system running, not just the subs. The beauty of RTA is being able to see exactly what happens as you're doing the adjusting.
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post #18 of 24 Old 02-22-2017, 11:38 PM
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For certain situation, there is a technique to gain and level match the subs. It is a complicated and not needed for most systems.
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post #19 of 24 Old 02-23-2017, 03:33 PM
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Whilst there's a lot of good info in there, there is a lot incorrect too such as the first table and statements such as this; "If you are going to put it in a corner, move a foot or so away from the walls so that the subwoofer does not become too boomy."
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post #20 of 24 Old 02-23-2017, 08:55 PM
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Whilst there's a lot of good info in there, there is a lot incorrect too such as the first table and statements such as this; "If you are going to put it in a corner, move a foot or so away from the walls so that the subwoofer does not become too boomy."
That is not an incorrect statement. The guy that wrote the post trained under Dr. Hsu. For anyone without measurement gear, this is the best guide that I have seen to date.

I won't post a link without it having some good info. There a 4 parts to the link and I have not found any link that is this comprehensive for bass management and a basic understanding of subwoofer, and standing waves with a good clear explanation of all that is going on in the small HT.

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post #21 of 24 Old 02-24-2017, 06:09 AM
 
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That is not an incorrect statement. The guy that wrote the post trained under Dr. Hsu.
He obviously didn't train under Paul Klipsch.
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post #22 of 24 Old 01-14-2020, 11:13 PM
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Hi guys,
Re-hatching this one after browsing some forums.

I currently have a fairly entry level 10'' ported subwoofer - https://www.jamo.com/products/s-810-sub
I'm moving into a different place with a bigger lounge area, and looking to get a SVS PB-2000 Pro.

My questions are:

Can I run both subs, I've heard 2 subs will make overall better consistent bass?
If running both, (SVS up front and the Jamo behind near the MLP) how would I "level" or "gain" match both of these so the Jamo isn't working as hard? I do have a SPL meter.
Should I scrap the Jamo Sub and run only the bigger SVS?

Cheers
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post #23 of 24 Old 01-15-2020, 04:04 AM
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Originally Posted by mraussieav View Post
Hi guys,
Re-hatching this one after browsing some forums.

I currently have a fairly entry level 10'' ported subwoofer - https://www.jamo.com/products/s-810-sub
I'm moving into a different place with a bigger lounge area, and looking to get a SVS PB-2000 Pro.

My questions are:

Can I run both subs, I've heard 2 subs will make overall better consistent bass?
If running both, (SVS up front and the Jamo behind near the MLP) how would I "level" or "gain" match both of these so the Jamo isn't working as hard? I do have a SPL meter.
Should I scrap the Jamo Sub and run only the bigger SVS?

Cheers
Buy the PB2000. Great sub. You could keep the entry level sub for now, but plan on eventually selling it and adding a second PB2000 to match.

Theater 1.0- The Foreclosure Theater: https://www.avsforum.com/forum/19-de...theater-4.html

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post #24 of 24 Old 01-15-2020, 07:30 AM
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Thanks for the tips.
How about 2 x PB1000's instead? Or still a PB2000 pro
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