Confidence in Auto EQ results?

LMO

When I first set up my PA system I ran auto EQ on my speakers and monitors outdoors. What I noticed then was that it always took a long time for auto EQ to finish, and the results were not always consistent for repeated runs. I didn't have access to a quiet outside area for this, so that may have been part of the problem.

Rerunning auto EQ this week in a small (120 sq ft) room with the ref mic at floor level gives different results than the original runs. Auto EQ finishes relatively quickly and the results are pretty consistent from run to run. Is it worth the effort to rerun auto EQ in a larger room (e.g. clean out the garage...) or are room effects totally eliminated by this method?

My ears seem to tell me that the Auto EQ settings improve the sound, but I'm wondering if there is any objective way to confirm that I am making valid measurements. The inconsistency between methods is a concern, as is the fact that the results are significantly outside the manufacturers' specs for these speakers. The Yorkville NX550P speakers test out much flatter than the RCF ART 310A speakers even though, by reputation, it should be the other way around.

Any thoughts?

Gadget

Indoor auto EQ is VERY problematic, but consistent as long as you don't move the mic, or speakers or add water bags...move to a different location.. get different results.. move speakers get different results...etc...
Outdoor Auto needs REALLY wide open QUIET (no I'm not yelling ) NO concrete or trees anywhere near.. nothing to slap back abd ruin the pass.. If there are such things... move the mic closer.. 8-10 feet for instance...

Remember even under the best circumstances the RTA based Auto EQ is a flawed process and each adjustment should be viewed with skepticism.. and just remember that your ears are the final say...what sounds good.. id good..
G

LMO

Another problem with the indoor method is that the mic element is too far from the floor, not nearly as close as a PZM would go. While I can see similarities between the Auto EQ curve and the published factory curve, there are enough differences to illustrate the weakness of this application.

I think I have the Auto EQ bug out of my system now.

Thanks-
Lynn

LMO

This is off-topic, but has anyone here used the JBL MSC1? It incorporates RMC: Room Mode Correction Technology. Is that fundamentally any different than Auto EQ run at just low frequencies?

Gadget

Lynn...
I have to tell you that there really isn't a LARGE community here like the PSW... we are a few dedicated individuals that try and mitigate the hype that comes out with the products...No Auto Eq isn't the hook it up, auto eq (who cares how you do it) and you get audio nirvana... every time... no it isn't even close, but the fact is, if you have NO experience, have NO idea what your doing... you can get closer to what your looking for, or you can at least start to learn what to look for and what the problems are...

The JBL system is just a different algorithm that still relies on RTA (frequency dependent volume information) to try and achieve a target product...As the guys on PSW told you, and I alluded to... some FFT measurement platform and a HUGE learning curve... are the only way to truly get the results your looking for. It may be that you need to just hire someone to tune the system for you...

Otherwise, launch yourself on a course that leads you to an intense learning curve, and the purchase of a minimum of software and equipment, but be prepared to attend lots of classes in order to get the best results with the hugely deep subject of system tuning...

The first thing that these tuning systems doesn't take into consideration is time alignment...or driver alignment within a given speaker...or any number of other factors that affect the sound coming from your speakers. Take ANY speaker that uses a woofer and a horn... and multiply the problems as the number of components increases... UNLESS they are all INSIDE the horn and time aligned like the Danley sound synergy horns do...then the sound source is basically a point source...and many of the problems associated with conventional systems and their deployment are no longer a problem.

Anyway, as the others at the PSW said... RTA based systems are not the answer...

Mike Kovack did a Auto EQ versus SMAART comparison, and within the boundaries of proper setup, the Auto EQ did provide "usable", repeatable results as long as a similar, common practices are utilized... those results are located in the old forum:
http://www.driverack.com/drug/index.asp
Where much of the groundwork for the techniques we use have been formulated...
Actually now that I think about it I moved it here...
viewtopic.php?f=60&t=957
In the FAQ section...

Well let us know if there's anything else we can do for you..
G
G

LMO

Thanks for all the responses. I set up the GEQ based on the frequency response given by the manufacturer, and the improvement is significant compared to anything else I've tried. It's one of those, "I didn't know what I was missing" deals, which I guess is all part of the process.

Thanks again,
Lynn

Gadget

You sir... are welcome...
G

James85

Jumping in..so if my speaker specs show a relatively flat response, then a dip at 15000 Hz, I would want to raise that band to achieve a flat EQ..while listening to a ref song?

Jim

Dennis

James85 wrote:

Jumping in..so if my speaker specs show a relatively flat response, then a dip at 15000 Hz, I would want to raise that band to achieve a flat EQ..while listening to a ref song?Jim

Printed speaker specs are the result of measurements taken in an anechoic chamber. There are no reflections. If you are measuring in such a chamber, then perhaps boosting 15K is the correct call. If you are measuring at a venue, the 15K dip is probably caused by a reflection which in turn causes a cancellation. If you move the measurement mic a foot, the dip might go away (or not). You would have to measure in several places and take an average.

Pink noise would be a far more consistant test tone than dynamic music. Save the reference song to use after the measuring is complete. You can then listen to a reference song to determine if you analysed the RTA data correctly and made the appropriate EQ changes

Gadget

To me it comes down to truth in advertising...(or outright LYING..) at the very least a case of smoke and mirrors...

No, with the differences in given drivers (even within the same batch), different batches and the like ..my guess is that they went through a LOT of speakers to actually find one that's even close to those specs... or perhaps they "smoothed" the response bumps right out...

Until they start having independent testing of the speakers published specs are no better than no better then ass wipe

Unless you paid BIG bucks for the speakers, or are using Danley products take those specks and throw em right out the window... they mean NOTHING! :shock:

As an example, Mikey, from this forum... illustrious engineer and system designer and tuner was working on an install.. using SMAART to evaluate the setup JBL SRX722... good speakers right? Brand new right out of the box ... here is the actual spec from JBL pro...

Frequency Response : 81 Hz - 20 kHz
(±3 dB)

Mikey couldn't get 12K5 out of the system... there was nothing above 12K in the speakers...curious in further testing there was a BIG difference from cab to cab, so he did a little investigating and found 2 totally different horn drivers in the cabs...even after JBL sent brand new drivers the speakers STILL wouldn't produce ANYTHING above 12,500hz :roll: They were NOT interested in commenting or addressing the issue, and Mikey is a consummate professional.

Needless to say he wasn't impressed with JBL in general...

Dennis and I are also not big JBL fans.. (Or Blose for that matter)

My $.02
Gadget

Guess I should have said "Don't get me started"

James85

Aarrrrg. You guys are always bursting my "simplicity" bubble.

Well..I'll ask another question and hope it won't break the "rules."
While I run MRX/LA400s for my local events..and they think I am "pro" simply because I apply a few basic PA principals and it sounds much better than what they are used to...I have a new situation. Our church has several installers quoting on line array systems for our new building. QSC and JBL are commonly in the specs. One installer now is carrying Meyer. I have always read the threads saying Meyer was an exceptional company. Would that be due to their fixation on quality control?
Appreciate your ever-helpful advice.

Jim

Dennis

All speaker companies exercise quality control but JBL and QSC offer lower and mid quality speakers to fit into certain price points. When you shoot for lower prices you have to compromise quality to achieve it and you will find a JBL or QSC product for most budgets.

On the other hand you wont find a Ford Focus or Honda Civic in Meyer's product line. They do not offer low or mid budget products. They offer only high end, high price equipment and it is easy to develope a good rep for high quality control when you offer no low end stuff. Example: so I am thinking I should invest in JBL Vertec but then I think to myself JBL JRX doesn't sound great, how much better does Vertec sound...................Of course Vertec sounds fine but JRX does not help sell it.

Dennis

James85

I get it-thanks.

Gadget

Also, Line arrays have become the "gotta have" tool for all applications, where in most cases there is a "right tool" for the job. Tell your board they should pick a sound company that uses prediction software such as EASE that will definitively tell you if a given speaker/system/or array is for your application... and not just one that wants to sell you the piece with the best "margin" for them....

Also, most reputable companies will "demo" a system for you (especially a line array) so you can see if it's going to fit the project. A good acoustician should be employed first to determine potential problems from the start.(especially in cases of lively, or difficult rooms. In some cases pattern control is the ONLY available "acceptable" solution... in that case, the speakers available are very few and far between...(have them look at Danley sound for instance)

Sorry if were making life difficult for you...were only attempting to dispel the myths, and improve the sound... one sound person at a time

G

Are you saying we suck because we make you think?

Dennis

Jim

When you get some screen shots of the installers prediction software for your church, post them here so that we can share more opinions.

Dennis

Gadget

BOY... have we got OPINIONS