Home Theater Forum and Systems banner

1 - 17 of 17 Posts

·
Registered
Joined
·
14 Posts
Discussion Starter #1
I'm finally starting to get a good handle on REW and make some good measurements, but am having some strange reactions from my Rane PE17 EQ. (5 channel analogue parametric EQ)

On the PE17 you've got 5 channels of EQ, each of them has -15dB to +15dB adjustment. What's happening tho is maximizing each of the dials only seems to net me a 4 or 5 dB change.

The following graph is my first real attempt where I've gotten results. The gold trace is un-eq'd with the mains off, and the blue trace is with EQ applied and the mains on, crossed @ 80Hz. (I haven't fine tuned overall level yet) It is also the result of 5 channels of EQ, all the level knobs set to either maximum cut or maximum boost.



Anyone else have this issue with the Rane? TIA!!

P.S. - subs are 2 Mach5 audio IXL18's, one in a 14ft^3 box tuned to 14Hz, the other in a sealed box, 5ft^3. power is a EP2500.
Mains are Jim Holtz Statements, powered with Anthem MCA30, pre-pro is Lexicon MC-1

Measurement system is Radio shack SPL meter with correction file, and a soundblaster live 24 bit external.
 

·
Registered
Joined
·
14 Posts
Discussion Starter #3
I'm going to hazard a guess that you have the frequency selector switches in the wrong position? Set them to 0.1.

Regards,
Wayne
Good guess, but I have got them set properly. I am able to effect change, but in much smaller incriments than I need, and than I'd expect...:dontknow:
 

·
Registered
Joined
·
7,514 Posts
I am able to effect change, but in much smaller incriments than I need, and than I'd expect.
Why not measure the Rane unit alone with REW and establish how accurate the settings are....

brucek
 

·
Registered
Joined
·
486 Posts
:huh: At 35 Hz. I see more than a 10dB gain. Also, what filters do you have set at band #3 versus #4? I saw this in the manual:

"For extra deep notching applications, use Bands 3 and 4 and set them exactly the same. Notches as deep as 30dB are possible, since Bands 3 and 4 are in series while most other bands are in parallel (see the block diagram in the data sheet)."

Try plotting just the sub (no mains) with the PE 17 bypassed and then with the filters applied. Then do the same with the mains on. Maybe the mains are canceling out what is going on with the sub.

:hide:

Maybe post what filter setting you are trying to apply so we can have that info also.
 

·
Super Moderator
Joined
·
9,252 Posts
Also, what filters do you have set at band #3 versus #4? I saw this in the manual:

"For extra deep notching applications, use Bands 3 and 4 and set them exactly the same. Notches as deep as 30dB are possible, since Bands 3 and 4 are in series while most other bands are in parallel (see the block diagram in the data sheet)."
Not relevant to our application, since we have no use for deep notch filters.

Regards,
Wayne
 

·
Registered
Joined
·
486 Posts
Not relevant to our application, since we have no use for deep notch filters.

Regards,
Wayne
I was just wondering if the two filters in band #3 and #4 might be fighting against each other. :huh:
 

·
Super Moderator
Joined
·
9,252 Posts

Just grasping for straws here...

I see you have large speakers. Are you running them full range? If so, that can blow out subwoofer equalization.

I assume you have all the bypass buttons off (both the global one to the left of the panel, and the individual ones)? The LED “bypass” indicators are counter-intuitive: They light up when bypassed, not when on.

What frequency centers did you use for the filters?

How long have you had this EQ? If you bought it used I suppose there’s a remote chance that someone had the gain pots changed out.

All else failing, I suggest you do what brucek recommended and run the EQ through REW. It will tell you for sure if the gain pots aren’t working right.


Regards,
Wayne
 

·
Registered
Joined
·
14 Posts
Discussion Starter #10
Hi All
Thanks for the ideas and sugestions so far. I plan to cross the speakers over at 40Hz eventually, or even run them as large, but right now I've got them set to small with an 80Hz crossover.

I did some experimenting with the bypass buttons, to make sure that they are bypassed with lights on and active with lights off. I could see consistant change from the un-eq'd when I turned the lights off, individual and overall.

My filters are currently set to:
#1 centered @ aprox 40 Hz, -15dB, .2 oct bandwidth
#2 @ 25Hz, +15dB boost .1 oct bandwidth
#3 @ 13Hz, -15dB cut, .2 oct
#4 @ 18Hz +15dB boost, .2 oct
#5 @ 25Hz, +15 boost, 1.2 oct.

I'll start from scratch again, with the mains turned off and present the comparison here. I'm also planning to do some experimentation using a single filter, switching from a -15dB cut to a +15dB boost @ the same freq and bandwidth.

Yes I did buy the Rane used and I am wondering if there is issue...
 

·
Registered
Joined
·
7,514 Posts
I have no idea how it would behave with parallel vs. series filters. Any thoughts on that, brucek?
It just implies that those two bands are wired additive I suppose. It just results in a larger filter than a single is capable of....

brucek
 

·
Registered
Joined
·
7,514 Posts
Have you got a link to instructions to help me learn how to do this? thanks!!
No link.

First clear the meter/mic cal file, then just hook up a single cable from line-out to line-in on the right channel and do a soundcard calibration, then take a measure of the cable from 0-20000Hz (after a Check Levels routine and Calibrate to 75dB routine) and ensure the result is flat... (this ensures your soundcard calibration is correct).

Then simply insert the line level device in that loop and take a measure. You have to fuss with the levels a bit, but you'll end up with a response of the device. Play with the controls and take some measures....

brucek
 

·
Super Moderator
Joined
·
9,252 Posts

My filters are currently set to:
#1 centered @ aprox 40 Hz, -15dB, .2 oct bandwidth
#2 @ 25Hz, +15dB boost .1 oct bandwidth
#3 @ 13Hz, -15dB cut, .2 oct
#4 @ 18Hz +15dB boost, .2 oct
#5 @ 25Hz, +15 boost, 1.2 oct.
Wow - well, there’s a big part of your problem, if not most.

#2 and #5 – two cascaded filters at 25 Hz, one very broad (1.2 octave), one ultra-narrow (1/10-octave)? What was the goal there?

25 Hz was one of the high points in the curve, and you want to boost it another 15 dB??

Your #3 and #4 are so close to each other that with that parallel thing, they’re probably largely cancelling each other out.

Basically, the idea is to match the filters with the problem area you want to address – e.g., don’t use multiple narrow filters if a single wider one will do. For instance, for that dip below 20 Hz, a single filter at 18 Hz would probably have been enough. 13 Hz is so low it probably isn’t worth messing with. Or, you could just use the low cut filter to dial it down.

Regards,
Wayne
 

·
Registered
Joined
·
14 Posts
Discussion Starter #15
thanks for all the help everyone! I think I'm finally starting to get things straightened out! my first issue was the difference between the # value on the setting and the what freq was actually being effected. they don't quite match up...
The values that I posted earlier were just the result of experimenting and trying to get my trace flat - I may well have been facilitating my own downfall by not coming up with a more intelligent plan from the get go!

I've done some more measuring, and I do indeed have -15dB and +12dB control. I've made some graphs to demonstrate this to myself. light blue trace unEQ'd, dark blue with narrow 15 dB cut, and purple with 12dB boost, centered just above 30.

This is with mains on at all times, still crossed at 80Hz

The other thing I did, which I should have done in the first place(!!) is turn the sealed sub off and measured just the ported sub. this makes adjusting and seeing the results of the adjustments much easier!:duh::ponder::coocoo:

I'll post again when I've done the full round of EQ'ing!
 

·
Registered
Joined
·
486 Posts
my first issue was the difference between the # value on the setting and the what freq was actually being effected. they don't quite match up...
I have the same situation with my Symetrix 551E eq. These analog eq's can apply filters to much lower Hz., but are not as easy to set-up as the digital (BFD, YDP, etc.) eq's. :nerd:

Keep at it. The results will be worth the invested time.
 
1 - 17 of 17 Posts
Top