Adjust Your X-over Then EQ or Use the Mfg Defaults Then EQ?

[toddalin]

For those of us who employ equalization to flatten the room response, do you set your speaker crossover to the manufacture's suggested settings then EQ the room, or adjust the crossover to the flattest response, then run EQ?

We've always used an RTA to first get the speakers as flat as possible in the seating area prior to running the automated EQ sequence. The reason is that the Yamaha YPAO only has a limited number of bands that it can adjust and goes for the "worst offender frequencies" first. It stands to reason (to me at least) that if I can get the speakers as smooth as possible at the seating area, the Yamaha will have an easier time and can turn its attention where necessary. Also, having constructed the crossovers, there are no factory settings.

Others (another site) noted that they use the factory settings and EQ from there because this is the way the speaker was meant to be "voiced."

I think that this "voicing" primarily applies to the testing facility's anechoic room (or whereever) and that is why the level adjustments are provided on the speakers.

How are others doing this?

[rlsound]

Set Xover points, then EQ.

[Eaulive]

Set Xover points, then EQ.

Agreed, adjust Xover first, then EQ.

[Tim Rinkerman]

I've always believed the fewer filters in the path, the better...get it as close as you can with the crossover before you EQ.

[Akira]

Others (another site) noted that they use the factory settings and EQ from there because this is the way the speaker was meant to be "voiced."

If this were true why bother having any adjustments at all. The purpose of the cross over pots is to compensate for the individual driver energy in a given room.

Always adjust for physics first and for electronics second. OR Correct physical problems physically and electronic problems electronically.

[scott fitlin]

I have always been taught to use the output level attenuators on xover first, and level match the ranges, THEN begin EQ,ing. We also use an RTA, go for flat, then add a slight HF curve, then adjust gain to compensate for EQ,ing losses, listen, fine tune by ear.

[boputnam]

Hi, Todd...

I'm a little late to this. You are asking about EQ'ing with a crossover, and then EQ'ing the room with another EQ? I'll chip away at this.

Yes, first use the crossover points and slopes recommended by the manufacturer. And, if this is a DSP and there are recommended EQ filter settings/presets, you could/should apply those. If there are no presets, then try and collect some near-field measurements on your own avoiding boundary affects (floor/wall bounce) and set some broad, gentle filters if needed to get a reasonably flat response.

Next, move the mic into the listening positions and collect measurements at each, and average the results. Use the average for room correction. If there are obvious anomalies, then apply additional filters or stack new filters over the first ones. But, use sparingly.

I've always believed the fewer filters in the path, the better...

Yes, oh yes. Filters = phase perturbations (= bad). Verified this numerous times at a recent Smaart training session, the outcome of which was "Fewer and Fatter is Better" when applying filters. Steep slopes at crossover points and high-Q filters do astonishingly ugly things to the signal phase.

The purpose of the cross over pots is to compensate for the individual driver energy in a given room.

Be careful with this. Using this differential gain techique to balance driver (band pass) output will move the effective crossover point - the amount of movement is dependent upon the crossover filter type and slope and the relative gain of the adjacent band passes (wrt unity). In one instance where the HF gain was dialed down to balance its output with the MF, the actual MF/HF crossover point needed to be moved 1/3rd octave down from the recommended point due to the effects of this differential gain - the result was the crossover occured where intended. Conversely, in a recent gig where the contractor brought ribbon HF driver mains whose output was much less than the MF (fatigue?). They compensated for this by reducing the MF gain - this had the unintended consequence of moving the effective crossover point between the MF/HF much lower than intended, increasing the work load being handled by the ribbon (and of course, increasing risk of frying it, and certainly accelerating it's fatiguing).

(edit: if this doesn't make sense without pictures, I have a DSP on the bench hooked to my laptop and can build some example voltage drives tomorrow, and post them - just ping this thread and let me know)

[toddalin]

Hi, Todd...


(edit: if this doesn't make sense without pictures, I have a DSP on the bench hooked to my laptop and can build some example voltage drives tomorrow, and post them - just ping this thread and let me know)

Thanks. Won't be necessary.

[Akira]

Be careful with this. Using this differential gain techique to balance driver (band pass) output will move the effective crossover point - In one instance where the HF gain was dialed down to balance its output with the MF, the actual MF/HF crossover point needed to be moved 1/3rd octave down from the recommended point due to the effects of this differential gain- Conversely, in a recent gig where the contractor brought ribbon HF driver mains whose output was much less than the MF (fatigue?). They compensated for this by reducing the MF gain - this had the unintended consequence of moving the effective crossover point between the MF/HF much lower than intended, increasing the work load being handled by the ribbon

Good point, certainly more of a risk in high SPL live applications. Still, with systems I have designed and know intimately with properly balanced components and 24db slopes, I will always adjust gain pots first. You can immediately tell a rig that is not balanced properly. (as above) This should not pose a problem in a system composed of properly balanced components.

Personally, (with the exception of blatant out of whack responses) EQ'g seems to kill that natural effortless response that a given box puts out. How many times have you shook your head and hit the half gain switch only to hear the rig come back to life? I would rather have a system that is a little more uneven but, floats with effortless fidelity...a quality EQ will never achieve. When the system floats, the room floats. Nothing is a fight, the sound is everywhere and the sound is effortless.

As in all things audio, cause and effect are intertwined throughout the chain. Your mains EQ effects your channel EQ which affects your gain sturucture and everything else in the chain. When I was heavily involved in SR, other techs were always looking at my gain structure and EQ and wondered, how do you get the entire console at unity with virtually no EQ. Just my way of doing things. I've seen other people with opposite philosophies get excellent results.

Getting back to the original thread... Big or small, simple or complex--GAIN STRUCTURE over EQ. At the heart of gain structure in any system is the cross over.