rear speaker calibration & subwoofer crossover questions -- help!

[supervij]

Hi All,

This was stupidly posted in the wrong section yesterday, so I'm posting it again. Sorry if it seems like I'm repeating myself!

First, a little background . . . I'm using a Yamaha RX-V750 for a receiver, all Athena speakers, F2 fronts, B2 sides, C1 centres (front and rear) and SB400 subwoofer. I've also got a Kenwood RFU-R6100 hooked up to the centre rear channel to make it "wireless".

When I do the Yamaha YPAO, the fuzzy sounds coming out of all the speakers are roughly identical in volume (so I figure the problem ain't the RFU nor the speaker itself). And the results are:

Front Centre 10.0 feet +4.5 dB small
Front Left 9.5 feet +7.0 dB small
Front Right 9.5 feet +7.5 dB small
Surround Left 5.5 feet +6.0 dB small
Surround Right 5.5 feet +6.0 dB small
Rear Centre 8.5 feet +7.0 dB small
Subwoofer 12.0 feet -7.5 dB crossover: 120 Hz

Okay, all the info looks weird set up like that. The posting thingie wouldn't let me lay it out all pretty-like, so sorry, everyone!

The fronts are small?! They always seemed like tall suckers to me, but okay. I've noticed that the dialogue seemed a bit low, so I pumped up the front centre to about +8.5 dB. The crossover seems a bit high, and the Athena sub (freq. response of 23 Hz to 120 Hz) recommends a setting of just under 45 Hz if paired with the Athena F2 fronts (freq. response of 35 Hz to 20 KHz). Should I go with Athena's recommendation of just under 45 Hz? Or Yamaha's opinion of 120 Hz? Or the standard that most everybody seems to prefer of 80 Hz? I've been trying to detect the audio differences for the three crossover points, but I end up confusing the heck out of myself, not to mention giving myself a bit of a headache.

Now, even when I pump up the rear centre to +10.0 dB (the maximum it'll go), I can still hear barely anything coming out of that speaker, even though the fuzzy YPAO sounds are roughly identical in volume from each speaker. So I figure I need to decrease the volume coming to each of the other speakers. But to what? I tried reducing each of them (except the rear centre) by about 5 dB, and that seemed okay. But something was off. I think the fronts were just a bit too loud. Or was it the sides? Again, I was listening so intently and to so many variations that my brain finally turned off in protest. So what I'm asking is: If I decrease the fronts by x dB, should the decrease of the sides also be x dB, or should it be a bit more, or a bit less?

Or is there something else I should consider, instead of decreasing the levels of the other speakers?

If this post seems confusing, don't worry, it confuses me too. Any advice would be hugely appreciated. (Or if any of you wonderful A/V enthusiasts want to come up to Toronto to set up the levels for me, that'd be okay too!)

much thanks to all who can help, and cheers,
supervij

 

[Mort Corey]

Sounds like you're on the right track. You'll be better off setting your X-over and leaving it at one place for a few days. I'd start at 80 but don't think I'd go down to the suggested 45 range. I suspect that your rear center is just not getting any information from your source. Very few DVD's produce 6.1 output..least that I've ever hear of. An Avia, or the like, setup disk and an inexpensive SPL meter are worth the investment. The YPAO to rough things out and the meter and disk to fine tune to your liking.

Just takes a little time....

Mort

 

[warpdrive]

You should keep all your speakers on small and choose 80Hz (and maybe go down a bit to 60Hz). You want as low a frequency as your smallest speaker can tolerate. Unless your main speakers can do 25Hz without straining your receiver, it's better to keep them "small" and let the self powered sub do the dirty work. So after you set the crossover manually, set the YPAO to skip the speaker size test, and do the others.

As for the levels, the YPAO should be roughly accurate. Some people bump up the center levels a bit. As far as the rears, the sound from the rears should never really be too obvious. Some DVD's don't have much sound coming from the rears.

It looks like the sub is set quite high, you might want to crank down the volume knob on the sub to balance the rest of your system, because everything else is +7 while the sub is -7. Turn down the knob on the sub a tad, and rerun the YPAO. After this is done, you'll have settings that are less extreme (say max is +3 and min is -3), and will give you more range if you want to tweak the setting up or down.

 

[supervij]

Thanks for your advice, Mort. I'll give the crossover a try at 80 for a few days, then try going down.

As for the DVDs -- there are some, just not enough. The Star Wars trilogy, Austin Powers 3, Gladiator -- these have 6.1. I know cos I have 'em! And it's not that I didn't hear anything at all coming out of the rear centre; I did, only it was incredibly quiet. Like I said, I had to put my ear up to the speaker just to realize that anything was coming out at all.

I'm starting to think that the YPAO does only a so-so job. I mean, the front centre speaker is ten feet away and gets +4.5 dB, yet the mains are only 9.5 feet and get +7.5 dB?! That's ridiculous! I think I may have to get an SPL meter. Are the analogs worth getting? I assume they're cheaper than the digital ones, and I don't need absolutely precise measurements right down to the millimeter. And instead of getting one of those Avia-type discs, I'll try out the THX optimizer on the Star Wars discs first.

thanks for the advice, and cheers,
supervij

 

[warpdrive]

On your particular receiver, there is nothing that YPAO does that you can't do yourself with a meter.

The analog meter is fine.

Your receiver should have test signals for setting the levels manually. Consult your manual. Using these to verify the settings for yourself with the meter.

My YPAO did a spot on job, but it's worth checking the settings anyway.

 

[supervij]

Thanks for the advice, warpdrive. My smallest speaker can go down to 50 Hz, so I set the crossover for that. I left all the speakers set to small. And I turned down the volume on the sub from 6.5 to 5. Ran the YPAO, and sure enough, all the values came between -3 and +3, just like you said. Of course, the YPAO now thought that the sub was 20 feet away for some reason, but I manually changed it, and other particulars, and now, honestly, the whole thing does sound a bit better. For whatever reason, I am getting a bit more out of that rear speaker. Hurrah! I think I will invest in an SPL meter. I have a bit of a hard time differentiating volume from all six speakers myself, and would like to calibrate it to a finer degree. Thanks again!

cheers,
supervij