T39 & OT12 First Test Drive with Crown XTI 4000 - Good but ?

[netwerks]

OK here's the latest.

Finally got everything done and hooked up yesterday for a quick test run.

Made sure I was getting 1.4v of signal into the amp.

Set XTI 4000 settings to dual A/B mode, crossed over subs @ 46hz-110hz tops @ 110-16khz both LR 48 pole and 46hz & 16khz set on LP/HP filters @ -15db (as far as it would go) and have "dsp limiters" set to -3db on both tops and bottoms. No EQ applied yet. (Well I cut about -3b between 2-4k to keep my head safe from the mids.)

Subs and tops are both running parallel.

I sealed the panels, triple checked for leaks no chuffing on any of the cabs. Also tested polairity with the 9 volt all are correct all the way to the amp speakon.

For testing purposes, I have both my subs together vertically placed 12" from the wall with horn mouth facing the wall, with both OT12 tacked and facing me about 10' away.

Garage size is roughly 20x20 and ceiling is about 9' tall.

First off, they sound great, clear and tight. Unsurprisingly, put a huge grin on my face but something seems off with the overall output of the system.

To balance my tops (2x OT12 301ho, 12piezo melded array) I have to bring them down @ 1/3 of the way which is fine and I expect that.

But whats odd is when I run this in a/b mode (summed) I turn both knobs on the amp up to full power in my garage and you can definately hear it, feel it and can still comfortably talk.

I would think it would be way way WAY louder than this in a 20'x20' space?

Am I correct in this assumption?

I am wondering if it's a sub placement issue or the size of the room causing cancellation?

I check the input levels and even if I put them to the red its like I feel that pretty loud and sounds great and full but "that's all I get?" and obviously if I bring them down there's even less output.

Output meters in band manager look like the amp is barely working, maybe bouncing to half power on the meters.

Even when I turn up both dials on the amp to full gain I am still only barely flickering the -10 light on the amp I would think at this point with rated sensitivity it would be deafining loud in this space.

I check the voltmeter seems it reads only about 5v and then bounces up around 30v (obviously based on cresting, fluxuation in levels)

I would think with this setup that even turning the amp up 1/2 way would be unbearable in that small of a space. Am I misisng something?

Anyone any ideas what to check, change or try?

It quite loud but like I say not "pants flapping" or to the point where its "dizzying" or I have to say "man that's just way too loud" and that's even with the amp running at full gain.

It's like i've got tons of headroom but really low output.

p.s I got it loud enough that it woke up a sleeping night shift police officer @ 6pm about 5 houses down. He came down and nicely asked me to turn it down as he could "hear it in his bedroom" so I guess I'll be taking it to the country for the next series of tests. I have a larger 35x35 outbuilding there.

[sine143]

You mention that you brought the crossovers down to -15db.

If' Im not mistaken, you are putting about 38 watts into each channel, less than that on the sub side due to the higher impedence.


seems pretty good if you can wake up Police in their own homes 5 houses down with the power of half a light bulb.


EDIT

is my math right? am I looking at this right? lol... hell if I know

[netwerks]

I brought the tops down that far kept the lows at 0db just to balance things out.

And that level was running the amp "wide open" what some may call "war volume" in my garage.

Seems like I should be getting much more output than this.

My assumptions were I wouldn't be able to turn it up half that high.

I guess a better question is if i'm only using 38 watts, it seems like that's all i'm getting?

Are my expectations too high?

Maybe i'm missing something...

[sine143]

how about just take your subs, and run a slow sweep from 5-100 (with your crossover on, so you dont fry your drivers with the low stuff)

http://sinan.ussakli.net/basstest/

I can definitely say that I can overpower my voice with this inside in a 20 by 20 room. In fact, I havnt even gotten it WOT with my 2000 inside. Outside, 2 T30s loaded with the delta 12lf in open field, (vplated) could set off a car alarm at maybe... 15ish meters. The t39 with the 3012 should be giving you more than that. A lot more.

Its wierd that the sub meter in the band manager isnt getting above half. If you are running full, and its bass heavy music, you should be gettin up there towards the top (or, -3 for you).

[Drey Chennells]

Hey man. I wont try to virtually dissect your setup but, I can tell you that for us (if I remember the voltmeter correctly) running about 10v nominal to 1 of our OT12 (deltalite/14 melded array) w/ no bass cab, hpassed at 90 or so, in a open,canopied portion (40'x80') of our shop its difficult to really talk well at 15' out. Further out it only gets better. Awesome throw. Beautiful,clear and balanced sound, very efficient and loud..I can only suggest you take another look...
Good luck,
Drey

[sine143]

yeah... this doesnt really help you either, but with my otops, standing at 3 meters, the "comfortable" listening level for me is when I turn the amp on, and turn the knobs up jussssst till sound starts to come out. lowest setting = comfortable. 50-60% = hard to talk if you are in the same room with them (sized ~ 25" wide by 60" deep). And I'm loaded with some crap drivers not the 3012HO. The piezos themselves are LOUD.

[SeisTres]

my j110's loaded with an mcm beta clone make you not hear anyone in front of them as far as 10 meters out. And thats with the melded array 10-12db down from the woofer section. at 1 watt off one or two meters it becomes unconfortable. And considering that the 3012ho should keep with the melded or maybe even overpower it, well....DAMN! but who knows, maybe your definition of loud is nowhere close to mine. Have you tried using the volt meter on the actual output that goes to the speakers(sorry, if you did, i must have missed it in your original post). And just for reference 100db will cover you voice and 110db your ears will ring for quite a bit afterwards.

[Bill Fitzmaurice]

I am wondering if it's a sub placement issue or the size of the room causing cancellation?

The size of the room. Long wavelengths need large spaces to avoid multiple cancellation modes.

[netwerks]

My question is not with the tops standalone, it's when I balance them out with the subs and run the whole system.

It's like to get to a level that really fills the room I have to keep the accelerator floored even though the car is on running (in my mind) 30mph.

I am going to try and measure actual voltage from the speakers tomorrow.

Rather than unseal the chamber I will create a dummy speakon with bare wire on other end and measure from the 2nd cabinet in the chain.

That way I can get some actual readings as to what's going on @ all the cabinets.

Don't get me wrong everything sounds great.

It just seems somethings amiss powerwise.


p.s. I'm very tenacious. If I wasn't, Id've given up a long long time ago.

[netwerks]

I am wondering if it's a sub placement issue or the size of the room causing cancellation?

The size of the room. Long wavelengths need large spaces to avoid multiple cancellation modes.

Bill thanks.

That was one of my assumptions and i've vaguely read in some other posts about people with similar results/concern.

I was very hesitant to make this post as I am being careful not to paint a perception that the design is at fault while at the same time want to share my findings and questions for others who will at some point be in a similar situation and ask the same questions.

With no EQ the rig sounds fantastic. Like I said before I was grinning like the cheshire cat (although my neighbor wan't) but I want to get this sorted and ensure I have followed the plans and best bractices to get the best out of my investment both dollarwise and time.

So with that I am turning to the community for a little help.

I will take it to a larger indoor spot tomorrow for further tests and do some more readings/ post my data and experience.

I will be posting a full build thread when all is complete.

[Bill Fitzmaurice]

Like I said before I was grinning like the cheshire cat (although my neighbor wan't).

Your neighbors aren't subject to the cancellation modes of the room, so they probably hear more bass 100 feet away than you do 10 feet away.

[bgavin]

Test it outdoors, where you can run it up without incurring the wrath of the locals.
This is the baseline where you want to dial in an 'outdoor eq' for future settings.

Make sure there are no reflective surfaces (buildings) within 2 wavelengths. This is typically 55 feet or so.
If you measure on a hard surface (parking lot), the signal above 200 Hz or so will be ragged due to reflections.
Measuring in a grass field will tame this quite a bit.

If you measure at 10 meters, 100w (28.3 volts) you will have a chart that is directly comparable with the published 1w/1m charts.

[netwerks]

I plan to do that in next week or so.