Working with REW

[cassb]

Hi everyone. I am new to this forum, but not new to music/sounds/stereos/etc. However, I must admit that I am at a loss as to what REW can do for me, and what my goal should be in my listening room.

A little background: What I want to do is configure my listening room for playing music mostly, and also for playing my Yamaha keyboard through, and limited use for movies or whatnot from my PC soundcard. So I just finished building 4 of Ed Frias' design of the "AR.com" bookshelf speakers. I bought a Panasonic SA-XR55 digital receiver to drive them. I don't know how to measure whether they are 'good' speakers or not - it sounds OK to me, but I have no reference point to compare to. These speakers also need some low-end help, which I started up a thread in your DIY Subwoofer forum to help with that project.

But I found and downloaded your REW program (excellent quality by the way - I'm a programmer too - and thank you for giving away all your hard work!). My goal is to play with speaker placement and the limited bass/treble controls on the receiver to come up with a good "live" sound. Can this program help me with that? I have run through the help file up to the point of "Making Measurements." So I made a measurement and have a graph. What do I do now??

Thank you!
Bryan

[brucek]

My goal is to play with speaker placement and the limited bass/treble controls on the receiver to come up with a good "live" sound. Can this program help me with that?

Yes, it can. Since you're measuring full range, hopefully you have a full range microphone such as a Behringer ECM8000 that allows that (since a Radio Shack meter that many people use for subwoofer measurements isn't really considered full range).

If you have a full range mic, then you can find the best placement that provides a smooth response. A bass and treble control are somewhat limited in their adjustment, but may be enough.

brucek

[cassb]

Ah -- so this program will only work with a subwoofer as the driver? I don't even have a subwoofer in this system yet -- I'm still trying to get info on how to build one.

So I need to wait until I get a subwoofer then to be able to place and tune my satellites? And yes, I am using the Radio Shack (analog) SPL meter as a microphone. I am looking for general or overall changes that will improve the listening experience. I guess I don't really expect to be able to fine tune my room acoustics to make it "perfect." So I would think that if the Radio Shack can pick up sound in the audible range (~40-12000Hz?) then I should be fine.

I think I'm at the point in the process now of "What do I do after I take a measurement?" Post it here? Move my speakers and try again? Move the microphone and try again? What am I looking for in the graph?

To summarize: Is there a procedure written somewhere, apart from just the mechanics of using the program itself, on "tuning a room using REW?"

[brucek]

so this program will only work with a subwoofer as the driver?

REW will work with any speaker(s) in any range you wish to test. You require a microphone that can do the same.

So I would think that if the Radio Shack can pick up sound in the audible range (~40-12000Hz?) then I should be fine.

And if the Radio Shack meter added a 10dB peak at 5KHz, how would you know if it was the meter or your system causing it?

"What do I do after I take a measurement?" Post it here? Move my speakers and try again? Move the microphone and try again? What am I looking for in the graph?

The full range measurements won't be meaningful if you use the Radio Shack meter. You should purchase a full range microphone and preamp for this task. The Radio Shack meter can be used full range for relative information only, but not absolute. This doesn't really help when you're attempting to set up for an even response at your listening position.

brucek

[cassb]

OK, I'll bite. How much and where do I get these microphones and preamps? I guess there's a price limit on my desire for a flat response. And that price is... hm... $20-$25? My guess is that these mikes and preamps are out of my financial comfort zone. So am I SOL then with trying to use this SPL meter with REW? Do you just 'play it by ear' then and move things around until it sounds OK? Or is there another option for poor people like me? :-)

[brucek]

See this sticky thread for information on the mic and preamp that is normally used with REW.

I'm afraid it's a bit more than $25......

brucek

[cassb]

Actually... hold that thought. My church has done a lot of EQ-ing of their equipment. I'll bet I can borrow the hardware from there to tune my room. I'll ask and see -- couldn't hurt.

So I should not even try using the Radio Shack at all, even though it's mentioned and illustrated in the REW documentation?

By the way, Bruce, I do appreciate your time and help. I don't want to seem rude or ungrateful.

[brucek]

So I should not even try using the Radio Shack at all, even though it's mentioned and illustrated in the REW documentation?

You can certainly use it, but I would limit the upper range to a few 1000Hz. After that it's a shoot....

brucek

[cassb]

brucek wrote:

You can certainly use it, but I would limit the upper range to a few 1000Hz. After that it's a shoot....

brucek

I'm glad you said that... I was getting discouraged. :-) I don't mind limiting the range to 40-3000 Hz if I can get somewhere farther with this SPL meter than just putting the speakers on the floor pointed at me.

So you're saying that the Radio Shack meter can 'color' the input because of its low-quality mic? I don't know much about this process yet, sorry. Does that mean that these meters are no good for measuring SPLs above 3KHz either?


Oh, and back to my previous question: To summarize: Is there a procedure written somewhere, apart from just the mechanics of using the program itself, on "tuning a room using REW?"

[brucek]

So you're saying that the Radio Shack meter can 'color' the input because of its low-quality mic?

Yes........

Is there a procedure written somewhere, apart from just the mechanics of using the program itself, on "tuning a room using REW?"

No.......

brucek