SPL Meters | Mic's | Calibration | Sound Cards

**ludwignew** · **11-15-08, 01:02 PM**

Well, I'm writing this post because someone told me that he adjusted his HT system using a PAA3 from Phonic.

He had an Onkyo TX-SR705 and did the Audyssey test. But to "time align" the subwoofer in an easy way without microphones and cards and stuff, he sitted in his sweet point and play a pink noise CD. Only the FR, FL and subwoofer were played.

In the screen of the PAA3 he saw the frecuency response at that point. He moved the phase control of the subwoofer until in the crossover frecuency a +3 or +6 db increase appeared.

What do you think of this "way" of subwoofer calibration?

**brucek** · **11-15-08, 01:38 PM**

Quote:

What do you think of this "way" of subwoofer calibration?

It's the easiest method of adjusting the phase on a sub for sure.

But why use a $400 spectrum analyzser when REW offers one for free?

brucek

**ludwignew** · **11-15-08, 02:03 PM**

Because someone lends you one of those? jajaja

thanks for the answer!!

**Wayne A. Pflughaupt** · **11-15-08, 04:53 PM**

Plus, the PAA3 is only 1/3-octave, while REW is 1/24-octave...

Regards,
Wayne

**thewire** · **11-15-08, 06:28 PM**

Quote:

Wayne A. Pflughaupt wrote:

Plus, the PAA3 is only 1/3-octave, while REW is 1/24-octave...

Regards,
Wayne

I never had noticed that before. What would one be sutiable for then?

**Wayne A. Pflughaupt** · **11-15-08, 06:42 PM**

Quote:

thewire wrote:

What would one be sutiable for then?

By "one" do you mean the PAA3?

Regards,
Wayne

**thewire** · **11-15-08, 06:49 PM**

Quote:

Wayne A. Pflughaupt wrote:

By "one" do you mean the PAA3?

Regards,
Wayne

Yes I mean the PAA3. I thought 1/3 octive was primarily not suitable for home theater use. The option is also in REW to use 1/3, so it must be used well for something?

**Wayne A. Pflughaupt** · **11-15-08, 07:18 PM**

The PAA3 was designed as a portable device for measuring and tuning pro-audio sound systems - i.e., systems in auditoriums. In large rooms such as this, 1/3-octave is the defacto standard (unless that's changed since I left the biz a good number of years ago). Which is perfectly fine, because there are no modes in large rooms like those.

In domestic systems, 1/3-octave would be suitable for full-range measurements (i.e., above the subwoofer frequencies).

Regards,
Wayne

**thewire** · **11-15-08, 09:30 PM**

I see. I was using 65536-point 1/48 octave RTA using Flat-Top window and 2 averages since I was not using Pink PN. I will try and use the 1/3 octave setting with the mains and see if I can get better results. For some reason I get better results with the White PN in the RTA than the Pink PN, but I see this is for the Spectrum analyser. I'm not sure I understand why using the spectrum is for the White noise, but I will try that also. Thanks Wayne.

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