Another First EQ post and some questions

**dguarnaccia** · **08-08-08, 02:14 AM**

Howdy all,

I've finally worked my way through some initial readings after calibrating the sound card, et al, and I think I have my first solid readings.

The room is 18x23, with a stairway/hallway in the back right corner.

I have a Marantz 7002 driving AV123 RS1000's in front, and a Velodyne servo 1200 placed nearfield along the sidewall about level with the listening position (just a tad in front). I used to crawl test to find the ideal location and this seemed to be it. The sub is crossed over at 60 hz, and the 1000's have powered woofers that I have going up to 120hz.

The room has Tube Base traps for accoustic treatment. They're similar to the ASC tube traps, but DIY jobbies. I have 2 16inch (total of 6 foot) in each front corner, and a 12 inch (6 foot tall) in the rear left corner. I also have 12inchers (6 foot) at the primary reflection points left and right.

The room has been calibrated with Audessy, and my first measurement, I have the Audyess filters turned on:

Yike, big hole there at 30hz... so then I try turning off the audessey filters...

Seems better (smoother) but a lot of peaking in the 50-60 range.

So, my questions are the following: Is it normal for audessy to be so off? Is what audessy is doing bad?

What are my option here? Can this be fixed by room placement, or do I need to invest in a BFD or something similar? Could more room treatments help?

I'd love any advice and suggestions you might be able to offer...

Best,

Darren

**brucek** · **08-08-08, 06:47 AM**

Quote:

any advice and suggestions

It's usually best to turn off the mains and take a look at the sub by itself to see how it reacts to the room. Then you can find its best placement without any other influence.
(Note that if your crossover is at 60Hz, then set the REW crossover target at 60Hz so you have a visual guide). Be sure to have your receiver/processor in stereo mode with no soundfields, effect, etc, turned on, then simply disconnect the mains and run the sub only.

Once you have the smoothest sub response, then turn on the mains and adjust the subs phase control to obtain the best crossover region response.

Then you can run Audyssey and see what it offers. If it's bad, don't use it... I'm surprised how poor it made the sub response in the first graph. I have no experience with Audyssey, but many plots on this site have shown it can do a good job, but sometimes not...

Quote:

Could more room treatments help?

The effects of room treatment is not observed in the response graph as much as it is viewed with waterfall for lower frequencies (to 200Hz) and RT60 for higher frequencies (200-500Hz).

brucek

**dguarnaccia** · **08-08-08, 11:20 AM**

super, I'll give that a whirl, thanks!

Ahah! Figured out the Audessy question...it was the dreaded 9db software bug in the marantz...basicially, you have to add 9 db to the Sub when using audessey, but when you turn it off, you are supposed to take it off again...it's a firmware glitch, but that should explain some of that..the sub was basically up 9 db when audessy was turned off ...silly me

**dguarnaccia** · **08-08-08, 03:01 PM**

Alrighty,

I turned off the fronts, and just ran the measurements with just the sub. After some experimenting, it seemed like the right side of the room was giving me that nasty spike, so I started moving it around to the front wall.

I tried up and down the left wall, and couldn't get ride of the spikes, so I switched to the front wall,

I tried left between the left front and center..here are the results

Then I tried the right side, between right front and center...here are the results...

Seems like the left side of center yielded better results, but let me know if I'm missing something..so I turned on audessy...(and added in the 9db from the bug)

So, assuming left was better, I tried bringing the mains back into the picture and here is what I got...

Here is the waterfall of the integrated setup as well...

Is this a reasonable result? I know I have a couple of sharp troughs, is that something I should worry about? I wound up moving the crossover up to 80 hz which seems to help the integration a bit better. I do have a large sub comming (mfw15) shortly that has more controls like phase and such that might give me more options, but it seems like my remaining problems are comming from the mains. Any other suggestions on what I should try?

Thanks again for the feedback, it's greatly appreciated!

**brucek** · **08-08-08, 03:49 PM**

Quote:

Here is the waterfall of the integrated setup as well...

set vertical scale from 45dB-105dB.
Set the horizontal scale to 15Hz-200Hz.
Set the plot to LOG from LIN - very important..
Set the time scale to 600msec.
Set x=1, y=100, z=150.

brucek

**Wayne A. Pflughaupt** · **08-08-08, 05:37 PM**

Quote:

I used to crawl test to find the ideal location and this seemed to be it.

The crawl test is for people who don’t have REW.

Quote:

Is this a reasonable result?

Doesn’t look bad overall. Looks like the sub level perhaps could be boosted a bit. The graphs that show a trough just south 30 Hz, that’s getting below critical range, at least for music, so it isn’t anything to lose sleep over.

Regards,
Wayne

**dguarnaccia** · **08-08-08, 07:21 PM**

Ok, I think I did this right...

Does that look correct for the waterfall?

In terms of boosting the sub level, should I just add more the the sub channel and try to smooth out the dips?

**Wayne A. Pflughaupt** · **08-08-08, 07:29 PM**

Looks like you have some kind of static noise in the room at 50 Hz or so. Lowering the graph floor another 10 dB or so would let you see it better. It would also allow you to see your signal decay all the way down to the room's noise floor.

“Adding to the sub channel” will certainly boost the sub level, but it won’t do anything for the dips...

Regards,
Wayne

**dguarnaccia** · **08-08-08, 07:32 PM**

So the only way to solve for the dips then is to apply filters with some sort of EQ like a BFD or something? Is that what folks normally do as a next step to diagnosing issues?

**Wayne A. Pflughaupt** · **08-08-08, 08:09 PM**

Not diagnosing (that's what REW does), but yes the BFD or other parametric EQ does a good job of smoothing out peaks and depressions.

Regards,
Wayne

**dguarnaccia** · **08-08-08, 08:42 PM**

Thanks muchly! Things sound significantly better already! Thanks Bruce and Wayne for your comments and suggests, you guys rock!

**dguarnaccia** · **08-17-08, 02:11 PM**

So, another dumb question...on the plot that shows the two sharp troughs at 97ish and 115ish hz, what can I do about those? Are those something to be worried about? I assume those are due to room issues with the mains since I've got teh sub crossed over at 80hz. I don't think it would be a good idea to try to EQ the mains, so how does one deal with issues at frequecies above where the sub covers?

**brucek** · **08-17-08, 06:26 PM**

Quote:

so how does one deal with issues at frequecies above where the sub covers?

Positioning is about the only way to deal with misbehaving mains with respect to ampitude problems, but yours appear fairly good... Certainly room treatament can help with reflections etc.

brucek

**Wayne A. Pflughaupt** · **08-17-08, 06:29 PM**

Well, those two places are fairly narrow, so fortunately they won't be terrible audible. Often these situations are the result of time alignment issues between the mains and subs that don't show up with the sub running alone. Often time alignment (aka phase) problems can be addressed with a variable phase control. But since you're getting them both with the mains/subs in tandem and subs alone, it's probably "just the way it is" in your room, at least at the position the measurements were taken. As brucek noted, repositioning speakers may be helpful. These are not the kind of problems you'd be able to address with equalization, either for the subs or the mains.

Regards,
Wayne

**dguarnaccia** · **08-17-08, 07:00 PM**

ok, thanks guys, I'll play with positioning a bit more and retest, but I won't sweat it too much...sounds like I really don't need a para EQ at this point. I'll wait to see how things change with the new sub (mfw15) if at all...

Thanks again

**DrWho** · **08-18-08, 12:53 AM**

Quote:

dguarnaccia wrote:

So, my questions are the following: Is it normal for audessy to be so off? Is what audessy is doing bad?

When you ran Audessy, was your measurement mic in the exact same location as the audessy mic?

One thing you might experiment with is moving your mic position around. It would be quite normal to see frequency response swings as large as those shown in your before/after comparison of the Audessy being on and off. So if Audessy thought it was fixing something at a particular mic position, then it is quite possible that it made things worse at another position.

Also, things like room noise can skew the results and screw up Audessy too. Did you have your air conditioner running during the tests?

**dguarnaccia** · **08-18-08, 01:21 PM**

I placed the SPL in the main listening position, at the same place I place the mic to calibibrate audessy

My audessy setup gives you 6 sampling points, so I did the main listening position first, then 2 feet left and right, then the last three measurements were all 3 feet in front of the previous measure points. I'd read that that give the system enough data to correctly compensate, but perhaps that was the problem.

I realize now that the weird 50hz signal in the waterfall is likely due to the minifridge, so I'll unplug that the next go around. I'll do the same for the Central AC just to be sure...

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