Do I need to run REW on my HT if using Auto Calibration

[carls64]

Do I really need to use REW if my receiver has auto calibration? I have a Yamaha 663 receiver with the auto room calibration feature, and I have run this a couple times to set everything but I am not sure if I should go ahead and run REW or not. Would I really benefit from using it?

I have two sub woofers and a 7.1 system/speaker set up. Although the Auto Calibration told me to set the cross over freq to max, not sure if that meant all the way to 120 or down to 50. The sub-woofers I have are not exactly the same, one is a DCM bottom firing 10" and the other is a Polk 8" front firing.

Any suggestions?

I have the REW software on a MacBook, and I believe I have calibrated it correctly. And I also have a Radio Shack digital sound meter.

[etcarroll]

Definately run it.

Auto cal. in a receiver is not 100% by any means, REW wil point out where it missed.

Having 2 subs only increases the chance of there being a problem, might as well find out now.

I'd set XO at 50 before 120, but really, 80 might be best if its an option. Try both 50 then 80. your ears should be your guide in this.

[carls64]

Well I am game for running it, but assume I know nothing Now that I have my sound card calibrated such as it is. I do not have a BFD so I would assume by the setup instructions I am going to use just the right in and out's. Right in on the sound meter and right in for the receiver?

[Wayne A. Pflughaupt]

Right out for the receiver...

Regards,
Wayne

[carls64]

I consider myself an intelligent person but I am having some difficulty figure out the specifics on what to measure for what type of connections. Most of the diagrams show connections to the BFD but none if you just have a receiver. And most seem to talk about measuring your subs/low freq. Are there any tutorials or step by step how to's. Sorry to be so ignorant.

[etcarroll]

Me too, and I had issues last month when I ran it, look for my thread, you'll see as I posted my issues, the experienced members here answered them. If you notice my first post, I outlined my equipment and room size, you can start there.

BFD is optional, not required, I don't have one.

You MUST HOWEVER read the first post, the stickied thread of REW info.

Find the 'GUIDES' section, then read the first 3 bullets, skip the 4th as its about BFD. I used this diagram from the guides section, minus the BFD part of course;

[carls64]

I must be doing something wrong during my sound card calibration. I seem to get it calibrated but when I do step 7 here, my measurement does not base out at 0 but like at 75db its flat as a pancake but not at 0 I am not sure what I am doing wrong.

[carls64]

Here is my initial sound card measurement, set at -12db I am in the yellow on the VU meters but in the green on the headroom of -6.x db

[brucek]

It's all fine. Save the soundcard file in REW and carry on........

brucek

[salvasol]

carls64 wrote:

Do I really need to use REW if my receiver has auto calibration? ...

It seems that you're starting to have fun calibrating everything after the build ...

Is okay to have two subs, but is preferred to have two similar ... by the way: Did you do the crawling test or just placed them in the front wall???

When you get REW running ... calibrate one sub at a time, then combine their response to get the best out of the system

REW looks intimidating, but after a couple of measurements you'll see how easy is to use

Hopefully you won't need a BFD ... after you run REW try to adjust the response with your receiver EQ (I have the RXV 2700 and that's what I did) and I'm happy with the results

[carls64]

salvasol wrote:

It seems that you're starting to have fun calibrating everything after the build ...

That's me! Backwards Carl I di the seating and screen size that way too But I came out okay there

salvasol wrote:

Is okay to have two subs, but is preferred to have two similar ... by the way: Did you do the crawling test or just placed them in the front wall???

Nope, I just stuck them there. I went for the hard way first

salvasol wrote:

When you get REW running ... calibrate one sub at a time, then combine their response to get the best out of the system

Ididn't think of that, THANKS!

salvasol wrote:

REW looks intimidating, but after a couple of measurements you'll see how easy is to use

I sure hope so.

salvasol wrote:

Hopefully you won't need a BFD ... after you run REW try to adjust the response with your receiver EQ (I have the RXV 2700 and that's what I did) and I'm happy with the results

I have the Yamaha RX-V663 I am hoping it has some way to manualy adjust things.

[carls64]

Do the BFD's make that big of a difference? And what about if you don;t have all the acoustical treatments, does it help? Lastly I am confused on which model to get if I did get one. They seem to be very inexpensive.

[salvasol]

carls64 wrote:

Do the BFD's make that big of a difference? ...

It will depend on your frequency response ... sometimes with the adjustment on the AVR and if you're not to picky, it will be okay.

And what about if you don;t have all the acoustical treatments, does it help? ...

The first step (before buying a BFD) is to get accoustic panels, bass traps, etc. ... that will help with the frequency response too, then get the BFD if need it ...

Lastly I am confused on which model to get if I did get one. They seem to be very inexpensive.

I think most get the 1124 ... it cost less than $100 price comparison yes:

I'm sure that the RXV663 and RXV 2700 are similar to adjust ... after the auto calibration, go to the main menu set up; you'll find the parametric equalizer, there you can adjust the sound (you have to play with that for some time until you get the response you want; what I did was to adjust one frequency at a time and use REW to see the changes; then another change and REW, then another and REW, etc.)

[carls64]

Here is my first and second readings there are from 0-200hz on the subs

[carls64]

If I go much above 200hz i get a message that I am getting some clipping.

[brucek]

Use the standard scale for subwoofers with your graphs.

Vertical axis = 45dB-105dB
Horizontal axis = 15Hz-200Hz

brucek

[carls64]

Here you go! Something still is not right though

[brucek]

Use the standard scale for subwoofers with your graphs.

Vertical axis = 45dB-105dB
Horizontal axis = 15Hz-200Hz

Measure subwoofers with the mains turned off and the subs fed from the receiver in stereo mode with the crossover set.

brucek

[carls64]

I am having trouble figuring out how to turn off my main speakers and leave on the subs :-( the manual does not seem to help, do i just need to disconnect the other speakers, that will not hurt anything will it?

[brucek]

am having trouble figuring out how to turn off my main speakers and leave on the subs

Unplug the speaker cables at the receiver (with the power off, of course). That's it......

You only need to disconnect the mains, since you always test with the receiver in stereo mode, so the mains will be the only speakers enabled.

No, it won't hurt anything. No speakers, no current.......

brucek

[carls64]

Ok that seems to be better but for some reason I can't see my baseline or what the corrected/actual value of the crossover should be.

Sub1
Sub2
Both

[brucek]

I can't see my baseline or what the corrected/actual value of the crossover should be

I don't understand what this means....

Change your graphs from LINear to LOGarithmic. Use the Freq Axis button.

brucek

[carls64]

Well it was showing me the base line of where the "should" be position right, like in those image:

http://www.hometheatershack.com/foru...tml#post113694

The blue green line there.

[brucek]

the base line of where the "should" be position right

That's the target response curve. It's enabled by selecting the target checkbox below the response graph. Its level is set with the target settings pane to the left of the graph.

brucek

[carls64]

Ok I found that, but what or how is it set? Where dies ti get its reference from?