calibrating subwoofer with spl

[cembros]

i finally picked up an spl meter (digital radio shack) and im trying to set up my speakers. I have the weighting set to C and the response set to slow. Iv gone through and adjusted all my speakers so that the db level is at 75 when the test tone plays a volume level 0. The problem is when i select the test tone on my subwoofer the spl meter reads 80 and no matter how i adjust the db level for the sub on the receiver. Please help

[Kryptron]

I used the same meter a couple days ago and had a similar result. I then looked at this thread and noticed the following...

The Radio Shack SPL meters work okay in the middle frequencies, but at low frequencies when using it for setting subwoofers, it can be off as much as 4dB. To get better results, you may consider a more expensive SPL meter, such as the Gold Line , Nady, Galaxy, etc.

[cembros]

well thats great news after i just spent 50 bucks

[Kryptron]

well thats great news after i just spent 50 bucks

Just take it back, radioshack has a 30 day refund policy.

[cembros]

ok just returned it, now to decide which one to get

[cembros]

recomendations would be nice. I looked at the recomendations in the thread about calibrating your speakers system, but cannot decide

[Big Daddy]

Corrections to Radio Shack SPL Meter
When using a Radio Shack SPL meter, you need to adjust for the fact that it's not accurate at all frequencies. Add according to the numbers listed below. These frequencies are 1/6th octave apart.
16Hz add 11.5dB
18Hz add 8.0dB
20Hz add 7.5dB
22Hz add 6.5dB
25Hz add 5.0dB
31.5Hz add 3.0dB
36Hz add 2.5dB
40Hz add 2.5dB
45Hz add 2.0dB
50Hz add 1.5dB
56Hz add 1.5dB
63Hz add 1.5dB
80Hz add 1.5dB
89Hz add 1.5dB
100Hz add 2.0dB
111Hz add 1.0dB
125Hz add 0.5dB

http://forum.audiogon.com/cgi-bin/fr...6&openflup&1&4
http://www.danmarx.org/audioinnovation/rsmeter.html
http://www.subwoofer-builder.com/SPL-corrections.htm
http://home.centurytel.net/rshannon/AVS/splcorr.htm

[cembros]

ah i wish u would have posted before i returned the meter. But i did read your thread about calibrating a home theater system so i think your advice would be best. For about 60 bucks what do you think the est spl meter would be. Thanks

[Big Daddy]

Originally Posted by cembros

ah i wish u would have posted before i returned the meter. But i did read your thread about calibrating a home theater system so i think your advice would be best. For about 60 bucks what do you think the est spl meter would be. Thanks

The Radio Shack SPL meter is by far the most popular. I have owned the digital version of the meter for the past 4-5 years and I am reasonably happy with it. Unfortunately, I don't have any personal experience with the other models and can't give you personal advice. You would have to rely on user reviews on Amazon and other sites.

[musicman1999]

I have the RS analog version and have had it for about 6 years and never an issue. To me it sounds like the volume control on the sub maybe to high.

bill

[olds403]

You should be able to adjust either the sub output on the receiver or the volume on the sub as has been mentioned. I am able to adjust my sub level out on my receiver just like all the other speaker levels, in either the dolby digital settings or the dts settings.

[bobbydrugar]

When calibrating a subwoofer and using test tones are most of you simply placing the system in stereo mode to engage the SUB or are there some good 5.1 or 7.1 calibration disks to help with the .1 channel. I do have the DVE HD basics Blu-ray but the test tones they provide are so fast like 2 seconds to adjust and next frequency I usually find that I like 15 to 20 seconds a frequency to make sure I am getting the average sound wave. I know most base is quick and its over but for calibration I think looking for the tone to normalize is the most non biased way to do this.

Thanks

[kareface]

I wouldn't use the RS SPL meter for taking FR measurements. But for setting levels it's more than adequate.

[bobbydrugar]

is there an SPL meter that you would recomend for FR Measurement

Thanks

[kareface]

Originally Posted by bobbydrugar

is there an SPL meter that you would recomend for FR Measurement

Thanks

The Galaxy CM-140 isn't bad. If you plan to do a lot of low range measurements you want to get a calibrated microphone, which might require a preamp. What are you looking to measure?

[bobbydrugar]

I have a small apartment with lots of neighbors and thin walls so when I listen to my system I am generally at lower volumes but ocassionally boomy bass in some frequencies prompted me to install a parametric EQ to flatten out the Bass response and allow for cleaner sonic joy without the need to keep jumping to grab the remote when something goes BOOM. Its not all of the lower frequencies but seems to be a couple areas in the 60HZ and 40Hz ranges. This has been with a garbage Onkyo HTIB Sub so now I have a new SVS PB12-NSD on the way (I know way over kill for my 400 SQFt apt its a studio in SF) but this will just mean that Bass control will be that much more crucial.

Thanks

[kareface]

What PEQ are you using?

[bobbydrugar]

Feedback Destroyer PRO Model DSP-1124P

[kareface]

Originally Posted by bobbydrugar

Feedback Destroyer PRO Model DSP-1124P

In that case if you are just looking to calibrate the sub the CM-140 will likely get you close enough that it won't be worth the difference in cost to get the more accurate option. The reason being, without room treatments and extensive calibration you likely won't be able to make such sweeping changes with just a PEQ that would justify the added cost. Make sure to grab a generic calibration file for the meter.

[bobbydrugar]

Appriciate the Help on this it has been a long uphill battle to beat these issues out. Unfortunantly room treatments are not really a big possiblity due to size of the apartment (I will be making a gallery soon need to get a better camera than my phone) and the restrictions on hanging or ataching anything to the walls fortunately with all the furniture and audio equipment and stands the room is practically an anecollic chamber as is

Thanks