REW noob...

[rossp]

Been playing around the last few weeks with REW as a total newbie on that front - using it mainly for subwoofer tuning right now. Have a Yamaha RX-V6A with AppleTV as the primary source, so limited options for minidsp or similar. Right now, I pulled the sub from my office into the living room so have two subs (both powered, one 8" and one 12") in this measurement. Generally to my ear it sounds ok - previously I was trying to get rid of boomy bass and this sounds better. My priority is music over movies, and earth shattering volume isn't a concern.... Like many of you, room space and WAF is a limiting factor - based on REW's room simulation it suggested my optimum sub position was right in front of our front door...
Thanks!

 

[Keith_W]

Welcome to ASR!

I think you forgot to ask us a question? What I think of that graph: wayyy to much bass, it is 15dB more than the main signal above 800Hz, and you have a huge dip from 45Hz down. Not sure what is causing that, most likely an issue with sub positioning. If you want to diagnose it, move your sub to another location that your wife will permit and see if it changes. You might want to knock down the volume of your sub by 10dB.

 

[rossp]

Yeah sub positioning/ balance is the key thing I am trying to work out. Previously I had a huge spike around 50Hz (from memory - not at my PC now) so trying to level that out a bit. That’s interesting re the high bass level - both subs are at maybe 25-30% gain, and to my ears didn’t sound excessive. Will play around with the levels some more in my next session.

 

[staticV3]

@rossp Please use a vertical range of about 45-50dB for loudspeaker frequency response measurements.

REW also has a handy screenshot button (the camera icon) for exporting graphs.

 

[Rednaxela]

Would you not try and optimize one sub and only then optimize further adding the other one?

 

[rossp]

Good question - that’s why I’m here I have been using one for a while, and only recently started playing with REW. The spike was with one when located in the couple of spots it could sit. The second one I had to hand, and is smaller so figured I’d try some different set ups - very much a learning exercise.

A related question, is there benefit to measuring just the sub(s) in isolation or always best to measure including front speakers too? The AVR is handling the cutoff frequency so I’d assume it shouldn’t make too much of a difference with or without the mains? Am I off base?

 

[LIΟN]

A related question, is there benefit to measuring just the sub(s) in isolation or always best to measure including front speakers too?

For accurate (or can do best on your device setup) alignment of the subs, it is recommended to measure separately without speakers.
Leave the microphone in the listening position to measure the speaker, set the acoustic timing reference to output, and measure each subwoofer.

 

[Keith_W]

A related question, is there benefit to measuring just the sub(s) in isolation or always best to measure including front speakers too? The AVR is handling the cutoff frequency so I’d assume it shouldn’t make too much of a difference with or without the mains? Am I off base?

It depends on what question you want to answer.

If you want to know how well the sub has been integrated with the speakers, measure both of them together.

If you want to understand the individual contribution of the sub or speaker, take separate measurements.

There are all sorts of ways to take measurements, each will give you different information. Even after using REW for > 10 years, I am still learning new ways to use REW. REW is like a measurement toolbox, there are countless ways to use it. Before you even place the mic and take a measurement, ask yourself what information you are looking for. Perhaps the measurement you intend to take may not give you that information. Perhaps you are better off doing a different type of measurement.

 

[rossp]

Thanks folks, plenty to chew on as I get started on this adventure……

 

[rossp]

OK have been working on this some more today - working on getting the main sub dialed in, and some eq on the front speakers to smooth out some of the spikes. This is as flat as I can get things with the (AVR built in) EQ I have. Have moved the sub to what sounds like a good spot (via the subwoofer crawl...) which helps smooth out some of the low bass spikes, but now have a null at 80hz. I guess that's the compromise in terms of positioning....
Had enough of sine sweeps for today - will spend some time listening to everything now and see how it goes. I also measured the sub with the mic close to remove the room impact, and the drop off from 45hz is the sub, so not a lot I can do about that currently. Ok, the fun continues. To my ears it now sounds a little bass light (I don't tend to listen at high volumes) but will keep as is for now and see how my ears adjust.