Rives Audio Test CD 2

[Alex2507]

I recently got an old EQ, a second sub and the test CD in that order spaced out across a couple of months. I'm out of work right now so I have time to play around with this while the wife is working. Room treatments will have to wait.

My first concern is the positioning of the RS SPL meter. Rives says the opening of the meter should face forward but it's not critical. Then why tell me to face it forward? They say to use 1k Hz @ 80dB as a reference. I used 500 Hz @ 70dB as 1k Hz on the R channel had a nasty dip and 80 dB would never go unnoticed by my neighbors. Does that sound okay?

The first thing I did was calibrate my channel levels and level matched the three sources I use (DVD, CD and 6 Channel). I use my receiver's L&R pre-outs to go into the EQ and then a 2 Channel amp. I am EQ'ing the speakers, not the subs.

A search revealed a post where Mtrycrafts suggested that the L&R channels be plotted and adjusted for separately. I did this but had both subs hooked up. Later today I'll try to plot just the subs separately and the entire system as a whole. How should I be approaching the plotting and adjustment process for 1 individual channel with 2 subs? I think that my previous method must be flawed and is responsible for a nasty 50 Hz spike. So far it's been good fun playing with this but I'm hoping to get some tips that take me to the next level (which is of course compromised by the level of gear that I have at my disposal).

My receiver's crossover was set to 60 Hz for this as it allowed me to apply equalization @ 63 Hz. Does that sound reasonable? The rec'r has a crossover slope of 12dB/octave and 1 sub pre-out which I have split. The subs have 24dB/octave slopes but I have them set to LFE so the x-overs are bypassed. How does that part sound?

Finally I am wondering how all that will fit into the 5.1 deal and if I will need to make further adjustments for that. That's enough for now.

Help a fellow audioholic take the next step ,

Alex

 

[bpape]

I think you're basically on the right track. Setting your xover up a little higher might help - especially with only 12db/octave slopes.

You will in fact want to measure each channel and sub separately so you know what's happening. However, in real use, they all play together so the blended output is what needs to be best. Sometimes you can adjust 2 channels separately but together, the measurement is completely different. In that case, you need to have known what each was doing so you can properly address the combination.

Same thing goes with the sub(s). Then, you get the fun of blending the subs to the mains. It's an iterative process but in the long run it will reward you with great sound if you take the time to do it right.

Bryan

 

[Alex2507]

I think you're basically on the right track. Setting your xover up a little higher might help - especially with only 12db/octave slopes.

I did end up doing that as an experiment to get rid of a dip @ 63 Hz. It helped.

You will in fact want to measure each channel and sub separately so you know what's happening.

I'm serious when I tell you that I plotted around 30 graphs. I now know that at my listening position I get better high frequency response with my vertical blinds closed with the concave part toward the room.

It's an iterative process but in the long run it will reward you with great sound if you take the time to do it right.

I had to look up iterative. After starting this thread I found a couple of threads by Buckle-Meister that talked this Rives business to death. I learned some things but the best part of the Rives deal is that it's a stepping stone to seeing how sound works. When you isolate 1 frequency and blare it through your room, you can hear the sound disappear by moving your head a few inches with upper frequencies. Also the sound comes to you from different walls with different frequencies. I would think that this would be a fine indication of where exactly you might benefit from room treatments and you could tune the panel for just that particular frequency if you were so inclined.

When it was all done I plotted both speakers and both subs together, it was fine. I also plotted Pro Logic II Music, it sucked. I listened to stereo and DD 5.1 of The Blue Man Group's I Feel Love from
The Complex. Dolby Digital was awsome.

 

[Alex2507]

EQ Settings

What should I do with EQ settings that fall below my crossover point of 80Hz? I'm not sure if I should leave them at 0dB or set them to -12dB. There are three setting that fall under the crossover point; 25Hz, 40 Hz and 63 Hz.

I am EQ'ing and amplifying L&R pre-outs only.