REW connection

[marcosreg]

I would like to know what the influence of processing sound in the response measured by the REW.
I have a Rotel RSP-1068 processor.
Front speakers are B&W 604 towers, center is B&W CC-6 and subwoofer is M&K V-125.
FR and FL are set large, center is set small 80 Hz, SW is set 80 Hz.
Should I use CD input with Pro-logic, or 7.1 RF and LF inputs?
If I use CD set to stereo, the processor does not route signal to the subwoofer, only to RF and LF.
If I use 7.1 inputs, I will have to send signal to RF, LF and SW simultaneously?
What about the center speaker?
Thank you for your attention,
Marcos

[Wayne A. Pflughaupt]

I would like to know what the influence of processing sound in the response measured by the REW.

I don't know what that means...

Should I use CD input with Pro-logic, or 7.1 RF and LF inputs?
If I use CD set to stereo, the processor does not route signal to the subwoofer, only to RF and LF.
If I use 7.1 inputs, I will have to send signal to RF, LF and SW simultaneously?
What about the center speaker?

Sure, you can use the CD input, or any other one that might be vacant. Bypass all processing - i.e., stereo mode, not PL or 7.1 - except for the subwoofer. Most receivers these days can be set up to utilize the subwoofer in stereo mode.

As for as the center speaker, you would put the receiver in Pro Logic mode if you wanted to take a measurement of it.

Regards,
Wayne

[brucek]

Should I use CD input with Pro-logic, or 7.1 RF and LF inputs?

Use the CD or AUX input and set your receiver to stereo. Set the mains to small and the subwoofer will be active.

Never use any soundfields (Pro-Logic, Neo, etc) since REW is a mono signal, and as such won't work with these schemes.

If you need to test a specific speaker with REW, simply connect that speaker in place of a main.

brucek

[marcosreg]

brucek wrote:

Use the CD or AUX input and set your receiver to stereo. Set the mains to small and the subwoofer will be active.

brucek

If I set my FR and FL to small, the sound processor will add a HPF (I can adjust it for 40, 60, 80 and 100Hz). My SW output is currently set to 80Hz.
Do you think I can run REW this way and latter (in normal usage) return to large? or I must keep it set to small?
Other question: When I run REW with the sound processor set to stereo, I know it has a flat response. After that, if I change it to PL, DD or DTS, will it add some bass equalization or it will only decode the encoded signal and keep the flat response?
(please pardon my poor english, it is not my mother language (portuguese)).
Thank you
Marcos

[brucek]

Do you think I can run REW this way and latter (in normal usage) return to large?

Of course. You're just trying to get the subwoofer active so you can measure. Usually you must set mains to small to get the sub active in stereo mode. Disconnect the mains when measuring the sub.

When I run REW with the sound processor set to stereo, I know it has a flat response. After that, if I change it to PL, DD or DTS, will it add some bass

You can't use REW with any of the soundfield modes turned on since it's a mono signal.
The standard use of REW is to measure a sub and then a sub plus mains to get a good crossover transition.

brucek

[marcosreg]

brucek wrote:

The standard use of REW is to measure a sub and then a sub plus mains to get a good crossover transition.

brucek

brucek

Thank you for your answers.
As my LF and RF speakers are large and have a good LF response, there is no HPF in normal usage. That means that from 20 to +/- 100 Hz LF, RF and SW are responding to +/- the same signals.
If I will adjust only the SW response through the BFD, I understand that the LF and RF speakers will continue exciting room eigenmodes. (and I have a large peak at 41 Hz).
How I will cope with this?
Also, I understand that to get a good crossover adjustment, I have to adjust gain and frequency for both, the HPF and the LPF. Is that correct?
Regards,
Marcos

[brucek]

How I will cope with this?

Well, it's a problem that I'm sure you understand that you're creating by allowing the sub and mains to share the same frequencies within the area of modal resonances, while you have no control over the mains equalization.

There isn't a lot you can do about the problem, other than stop using your mains speakers as large. I'm sure they're quite capable, but there's no reason to not operate them as small and perhaps to satisfy your feeling that you're cheating your nice speakers, maybe choose a 60Hz crossover.

I understand the feeling. I have a set of mains that are considered very capable (~$11K), and I felt kinda bad when I got them and so to satisfy myself that I didn't waste my money, I use a 60Hz crossover (on the mains only, the rest are at 80Hz). It still causes some small problems, but nothing like I would suffer if I ran them as large and tried to operate a subwoofer too.

So, what about giving 60Hz a try for the mains.

brucek

[marcosreg]

brucek wrote:

So, what about giving 60Hz a try for the mains.

brucek

Thank you brucek,
I will try this as soon as my new sound card arrives.
Marcosreg