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Subwoofer calibration problems (1 Viewer)

Jeremy D

Auditioning
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Aug 11, 2002
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6
I recently purchased a Paradigm PW 2200 and am having problems with booming. I'm pretty sure on the placement of the sub but I can't seem to get a good blend with the other speakers. I set the crossover on the sub at 80, the sub volume at half, the sub/sat phase at 0 and used my receiver's test tones and Radio Shack's SPL to set the sub channel level to match the others at 75 dB. I normally listen at about 70 dB to 65 dB depending on the movie. The sub is connected to my receiver's Pre Out. I have tried fiddling with the settings a bit but with no luck. Any suggestions? Any help you can provide would be appreciated. Thanks.

Receiver- Marantz SR 7000
Front and Surround Speakers - Paradigm Studio 20's
 

JamieS

Stunt Coordinator
Joined
Feb 17, 2003
Messages
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Do you nean the crossover on the back of the sub at 80 mhz?

If so what is the crossover on your receiver. I am not 100% familiar with the 7000 and I could not find the specs BUT I am guessing it has a fixed internal crossover of either 100 or 80HZ? So unless you can set the RECEIVER crossover to like 60hz or below you are getting a cacade effect from the crossover in reciever and sub.

I have a PW2200 and have the receiver crossover set to 80 the one on the back of the sub is at 150 (basically defeated). You don't want any interaction between the 2. You might be having the reciver send bass starting at 100 that the sub is REJECTING until it drops below 80 or below. Hope this helps
 

Zack_R

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Joined
Nov 4, 2002
Messages
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It may be that your sub and mains are *too much* in phase and giving you a 3db or more peak in the crossover region. This can make it sound boomy.

If the sub has a phase control you can manipulate it to a postion that partialy cancels the crossover to make for a more natural blend.

If your sub does not have phase but your receiver let's you specify speaker set-up distance, then change the speaker distance. By saying that the sub is either closer or farther away from the listening postion, the delay will be increased or decreased and give a similar result aas if you had a phase dial. Plus you can make the changes from your listening postion via the remote.
 

Jim A. Banville

Supporting Actor
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Jun 20, 1999
Messages
630
It may be that your sub and mains are *too much* in phase and giving you a 3db or more peak in the crossover region.
I doubt a small 3 db peak at the xover frequency would cause this boominess. The peaks and dips in the bass region in the typical system in an average room are much greater than 3 db. And speakers can never be in "too much" phase.

Jeremy D, I suggest you measure the frequency response of you sub and mains playing at the same time over various frequencies using some test tones to see what kind of interaction is going on. Measure the mains alone at first, then add the sub and see what kind of differences you measure over the entire bass range from an octave above the xover frequency, all the way down to 20Hz. Do a search for "test tones" here and you'll find plenty of sources for them. What caused you to choose the "0" phase setting? Since you say you aren't using the reciever's "LFE/SUB" output, I'm assuming your main speakers are not having their bass rolled off. You sub and mains are probably producing the same bass frequencies over a wide range. I can try to e-mail you some bass test (warble)tones to use. You set your SPL meter to 80db, C weight and SLOW response, and put it where your head would normally be. You then write down the measurements from the mains alone through the ever-declining bass tones. You then turn on the sub and play the same set of test tones while you fiddle with the phase and level controls while noting any changes (+/-) to the first set of measurements. If your receiver doesn't have a highpass xover to eliminate the bass from your mains, you may need to route them through the sub's highpass xover to smooth out the response if you get way out of wack response with the mains playing full range.
 

Jim A. Banville

Supporting Actor
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Jun 20, 1999
Messages
630
I can e-mail anyone a 2MB Mp3 of bass warble tones that start at at 200hz, and go down through 160, 125, 100, 80, 63, 50, 40, 31, 25 and 20Hz.
 

Jeremy D

Auditioning
Joined
Aug 11, 2002
Messages
6
The crossover on the sub is at 80 Hz and according to the manual the receiver sets the crossover at 100 Hz. In the receiver's setup options the LFE level defaults to 0 dB but does give you the option for -10 dB. Right now I have it at 0 dB. The receiver does not give me an option for entering speaker distance for the sub. I double-checked and made sure all other speakers were set to Small. This is actually the first sub I've owned that has a Sub/Sat phase alignment dial. Since I wasn't certain how to set it up and the PW manual is a little vague on how to use it (it states turn the dial until you hear the most bass), I decided to go with 0.
 

Lee Bailey

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Jun 8, 2000
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Lee Bailey
Jeremy,
Doesn't the sub offer an input bypass mode? Whereas you let the receiver's crossover do the work instead of the sub? If so, you need to use it. Your other option is to use the speaker level inputs on the sub instead, and use the sub's crossover. Though you would still want to set it to a 100Hz crossover point, since any speakers set to small in your receiver will have their output redirected at 100Hz. After that, when you perform some measurements, your peaks are probably related to the room more than anything else. But first, you have to eliminate the interaction from using 2 crossovers(receiver and sub).
 

Jeremy D

Auditioning
Joined
Aug 11, 2002
Messages
6
Ok I set the sub's crossover to 100 and most of the booming has been eliminated (what's left I would attribute to room acoustics). It also cleared up an issue I was having with not being able to understand quieter dialog. Now it's just a matter of fine tuning. Thanks for all your help everyone.
 

Alan Pummill

Screenwriter
Joined
Jul 6, 1999
Messages
1,262
Zack, Jeremy,

After reading this thread, I got out the old Avia DVD and my trusty Radio Shack SPL meter to calibrate my PW-2200.

My final settings are with my receive crossover at 80Hz, the sub at 150 Hz, and my phase "near" 0 phase setting. I have the sub volume set at the mid-point, 12 o'clock.

I must have, over time, messed with the settings since my last calibration. The sub sounds much, much better than before.

Thanks for reminding me to re-calibrate. I had a group of fellow HTF members over for a Local HTF meet last Saturday. One of those attending brought his SVS 25-31 PCi. It out did my PW-2200, but I think my calibration was off. I will have to admit, the SVS was awesome!!

Jeremy, set the sub to 150 Hz and see what that does!!;)
 

Stephen Hopkins

HW Reviewer
Senior HTF Member
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Jul 19, 2002
Messages
2,604
As others have said, just turn the sub crossover all the way up, which essentially eliminates it's effect. This way the receiver's crossover is doing all the work and will eliminate any cascading due to multiple crossovers being applied to the signal.
 

Jeremy D

Auditioning
Joined
Aug 11, 2002
Messages
6
Ok I set the crossover on the sub to 150, sub level to half and phase to 0. I then borrowed a copy of Aiva from my friend. I started to set up the sound at reference levels per Aiva. My question is this, when I referenced the speakers to 75 dB on my receiver the speaker channels levels were set to this:

Front R & L, Center 0
Surround L & R, -6
Sub -3

Now when I attempted to set reference levels for Aiva at 85 dB the Front, Center, and Surround channel levels stayed the same, but I could not turn the channel level on the receiver down far enough to get the subwoofer to read 85 dB. At the receiver's lowest channel level setting (-15), the SPL reads about 90 dB on Avia's test tones and strangely reads 68 on the receiver's test tones (the other speakers still read 75 dB). Is this normal? Should the sub's channel level drop so noticeably compared to the other speakers? Should I turn the subwoofer channel level on the receiver up six or seven decibels to compensate? Or do I need to lower the sub's volume control a little so I don't have to turn the receiver's channel level all the way down to match Aiva's test tones? This really has me confused and if someone could explain this to me I would appreciate it. Thanks.
 

Geoff L

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Dec 9, 2000
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Geoff
Ignor the receivers test tones, use Avia to calibrate all channels.

Per your sub cali question:

Put the receivers sub level at it's mid point, then (turn the powered subs volume control down) till you get the proper spl meter reading.....
 

Jeremy D

Auditioning
Joined
Aug 11, 2002
Messages
6
All right! I made the suggested changes and tweaks and now everything sounds great. Thanks a lot everyone!
 

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