Hello all,

I just bought some speakers that a local SR company built. They had built new speakers along the lines of the EAW KF300e. They (their new speakers) really sound good. McCauley 15's etc.

Anyway I now own 4 semi-horn loaded Eminence Kappa Pro 15's, (I really can't tell you the exact cabinet design of the 15's), two 10-in horn loaded JBL's and some (I don't know the brand) HF horns. Each cabinet has only one driver. Four 15-in, two 10-in and two compression driver loaded horns. I don't know the dispersion pattern of the HF horns.

The owner of a SR company I roadie for told me the drivers in the HF cabs were very sweet and that I got a great deal on the equipment. Nothing like a little positive mental reinforcement after purchasing USED equipment. Like I said - all Home Brew cabinets.

I have sat in local clubs and listened to these very cabinets with subs and I always enjoyed the show. That was with a great guy at the mixer. J.T. Huff of Fayetteville, Ark.

I read the two articles in the Study Hall
www.prosoundweb.com/studyhall/studyjump.php?pdf=Impulse_Alignment1
www.prosoundweb.com/studyhall/studyjump.php?pdf=Impulse_Alignment2

Anyway, is there a relatively inexpensive device (like the one described in the Study Hall document) available to test a sound system for correct polarity. I have always paid close attention to wiring when setting a system up and plugging it together.

I just want to make sure I'm getting everything set up to get the optimum quality from what I have to work with. It is my first run with the Neutrik NL4FC connector so I think I need to take special care.

I am NOT a pro sound guy. I am working on getting there as best I can.

I have a Peavey Autograph that I rarely use. When I do use it, it's just for a basic room EQ. Just to find any extreme peaks. I have the PVR-1; at least I think that's the Mic. It is the little calibrated condenser Mic that Peavey recommends. I do own an O-Scope, B&K 15Mhz. So I have most of the equipment.

How do I generate the frequency specific impulse? Is this truly necessary?

Thanks for your patience and any advice you can offer.

Miles Langham

Reply posted by D. Parker on August 19, 2000
-"I have the PVR-1; at least I think that's the Mic. It is the little calibrated condenser Mic that Peavey recommends."

Watch out with that mike. I owned 2 of them, one went loco and it was obvious. The other went out of whack and it wasn't so obvious. It had peaks and valleys 6 or 8 db. The autograph has correction factors for several mikes, try a couple of other mikes and make sure PVR-1 is functioning properly.

David

Reply posted by Miles Langham on August 19, 2000
That is a great idea. However I don't know where to get the mic checked. I do know it hasn't been dropped. I guess I can send it to Peavey for testing.

Thanks

Miles

Reply posted by D. Parker on August 19, 2000
The one I had wasn't hard to find fault with. If you have another condenser mike, use it to RTA a speaker and make a note of the readings, then RTA the same speaker with the Peavey mike. The one I had had these huge dips and peaks that obviously weren't right.

You could hear it if you plugged the mike into the board and spoke into it. I just wanted to warn you so you would be aware, I don't think you would need to send it out. You'll be able to tell. If it's .5db off here and there you won't be able to tell that, but mine was off 6 or 8 db in the peaks and valleys.

David

Reply posted by david b. on August 19, 2000
Just a couple things:

1-) You can test polarity with those dedicated boxes: one sends a click thru the system, the other you hold as near as possible to the DRIVER you want to test. It has a built in mic. The LEDs will tell you if the driver is "in phase". Testing by ear, if the woofers are wired in opposite polarity you will get a decrease in LF .If the tweeters are wired in reverse, when playing some music in mono, you will notice that immediately: sound should come from the center and not spread all the way between the speakers. Also, while moving your head just slightly from side to side, you will "lose" one side.

If the tweeter is in opposed polarity with respect to the woofer, the sound will not "combine" smoothly, you will notice a "hole" in the space between the drivers.

2-) The Autograph will not help you "tune the room". For doing that, you need several pounds of dynamite. What you can do is bring your speakers to sound flat at the near field, by placing the sampling mic at some 1 meter on axis in front of the speakers and then let the A/graph set itself to a flat curve. At least you are flat at the source. It might or might not sound good to your ears but it might be a good basis upon which to build your sound.

Hope I helped a bit.

David B.

Reply posted by Miles Langham on August 19, 2000
Thanks David,

I was hoping to use the Autograph to help me find the crossover points. Such as where a cabinet starts to get near the down 3db point. I don't use the Autograph for anything anymore. It's a pain to try and use as an EQ only and I prefer my ear to set the room EQ over an analyser unless I just get baffled (take a shot Triple J it's wide open)

I guess I'll just ask the guy I bought them from where to crossover each cab. I was hoping to learn a little something.

Thanks for your help David. Still trying to get the money together for real subs.

Miles