setting gain

trshot

If my amps and speakers are listed in the DRPA and I use the wizard to configure everything, do I still need to do a gain structure? When I add the amps to the DRPA program do I simply match my amp attenuators to the wizards settings or do the gain stucture and match the DRPA to my amps?

Gadget

Yes you still need to do the gain structure.. it's easiest to just leave the DRPA xover gains near unity and use the amp controls to turn down the louder components... The Read ME First before posting has lots on this...
G

Dra

You can't change the DRPA's sensitivity. The wizard is simply what some guy(s) came up with for the equipment combos. It is best to do a manual gain structure and subsequent system balancing by reducing the loudest amp(s) AND THEN compare to what the wizard says. If it is not close then something (you or the wizard guy) is wrong.
If you feal inadequate, use the wizard (and assume that the wizard guy wasn't sniffing glue at the time).
If you want to be sure (and learn something in the process) do it youself.
Read the READ ME FIRST section above.

DRA

trshot

Hi Gadget & Dra!
I've read and reread the RMF's to the point I think I over think the settings with the DRPA.I'm a drummer who does the sound (onstage) for my band,so please bear with me in this gray area for me.We are a top 40/rock band and play 100-500 person venues. I downloaded the \"pink noise\" track,did the gain sturcture and wasn't happy with the result. It seems like I've lost power (volume) at the mains & subs. I know you will want the settings/tunings, I can't get them right away cuz the PA is packed in the van and we have house sound this weekend. Let me start with what I have for a system. I will do another gain structure and note how I did it just incase I missed something.

A&H wizard
Crown XTI 2000(bridged 1900@4ohms) mains
Crown CE 4000 (stereo 1200@4 ohms) subs (am I underpowered)
JBL SR4725A Mains (600 rms @ 8ohms,chained down to 4ohms)
JBL MR528S Subs (1200rms @ 4 ohms)

The DRPA had the CE amp but not the XTI, so I used the CE2000 as it was the closest match to the XTI2000..
The SR4725A was not there so I used SR4725X instead. I used custom for the subs as they are not in the DRPA either. The 2.0 upgrade chip is on the way to me and everything except the 4725A's will be in the upgrade.
How does it sound so far? I know you will want/need settings. I did use the wizard to set everything up,NO comperssion,x-over at 110db down to 37db, don't remember what the limiter,gain or threshols levels are, but I'll get them ASAP...

Now it's suck up time....
Thanks for a quick response, I look forward to seeing if we can get this system at full potential..

Dra

What was your set-up before (include where the amp attenuators were).

DRA

trshot

Here's a long answer, just want you to have all the facts....
As mentioned before, I'll have to post ALL the settings next weekend as the club I'm at this week has a house pa. My rig in packed up in our van.

Originally I had a well known sound company set up the DPRA. They turned the amps all the way up. When I questioned why, I was told everything was protected by the limiters. I left that program in the DRPA and did my own set up (gain structure) the amps were both very close to each other,around 2-3 clock on the gain. When I played out with that setting it was worse, very little bottom. I had to push the main on the board past unity to get \"decent\" volume. So I reverted back to the sound companys program and turned the amp gains full up again. I always moniter the amps for clipping, when I push the board..
A side note,With the sound co's settings, When I'm just below or at unity on the mixer the threshold (?) (top led's) leds are always blinking yellow on both high & low output leds ( I run the mains in mono)

Dra

What they gave you was a car that will go 0-60 in 6 secs. The problem is that when you try to go 70 your car over heats. The gain structure may limit you you to 0-60 in 10 secs, but now you can go 70 with no problem. Which is faster, 70 in a Escort wagon, or 70 in a Mustang? (A stretch I know).
Yes, you will have to push the board harder than before, but your amps and speakers will thank you (while giving equal output).
Does that make sense?

DRA

trshot

Funny, I own an auto repair shop, so your talking my language, I think!

So what your saying is,
Leave everything as is (gains all up) and push the board! Should I assume (uh oh!) the blinking threshold LEDS are ok? If I push the board (just above unity ) the CE 4000 (subs)will clip. Back to forementioned comment, am I underpowered on the subs? Here's a new question..I just got a pair of JBL SR4732A's. I'm thinking,I'll run each on an XTI2000 bridged. The RMS is 1200 per box and the amp will put out 1900w. When I add these to the system setup do I turn up the gains as well and if so will the limiter need tweeking or just reuse the present setting?

btw DRA,
Thank's for such fast responses!

trshot

Dra,

I just reread you last reponse, I believe I missunderstood it while I was multitasking! It sounds like you were saying to DO a gain structure, correct?

Dra

I'm glad you re-read the post. Yes, wide open amps are clips waiting to happen. Better to fill all the yellows on the board than ever hit a red on the amp. Most speaker builders recommend 2x RMS power. So for your 1200w RMS cabs, the amp should be 2400w at whatever the load of the cab is. For subs you can go 3x if you are carefull. That does mean that you can feed a 1200w cab 2400w of highly compressed (all on, all the time) music (or continuous power), but that the nature of music is hit and relax, hit and relax, etc. Also consider that a clipped signal more than double the output voltage of the amp and that is a ton of coil melting power.

DRA

trshot

Thanks Dra,

I knew the rule was 1.5-2x's the RMS on amp power. I was told by the Pro shop that the CE4000 \"should\" be ok with the MR528S bottoms. I was trying to not have a ton of amps to move. As it is I have 5 in a rack for my FOH and MON\"S..I'm always concerend with AC power in the clubs and try not to overload circuts. Jeez. is there a happy medium!!

Dra

Crown XTI 2000(bridged 1900@4ohms) mains
Crown CE 4000 (stereo 1200@4 ohms) subs (am I underpowered)
JBL SR4725A Mains (600 rms @ 8ohms,chained down to 4ohms)
JBL MR528S Subs (1200rms @ 4 ohms)

Right now your running 3x to the tops and 1x on the subs.
It's not that you are underpowered on the subs, because there really is no such thing, but you are limited by the available sub amp power as it relates to the tops amp. As is, you are \"wasteing\" 2/3 of the available power of that amp.
Set the gain structure on the sub amp and keep it there. Then simply balance the level of a good CD by turning down the tops amp.

A bridged CE4000 on each sub would be nice. So many options, but they all cost money.

DRA

trshot

Hi DRA,

Sorry, I may not have been clear about my tops. I am running one XTI2000 bridged to both tops. The tops are paralled(?) to bring them from 8 to 4 ohms. If they are rated at 600w cont. @8ohms do they stay at the same 600w rating when paralled down to 4 ohms?

So Dra, here's what I have for amps 2 CE4000's ( bought one to use with my new 4732 tops) and 3 XTI 2000's..I NEED 1.5 XTI's for mon's.
Does this sound good if I run this way,
both CE's bridged to each sub and keep the one bridged XTI to the parelled tops? Also to add more confusion :? , I mentioned I bought SR4732A tops to replace the 4725A's. the new tops are rated at 1200 cont @ 4 ohms. if I get yet another XTI2000 :shock: I can then run bridged XTI's to each tops and bridged CE4000's to both bottoms...Then hope I don't have AC supply problems in the clubs,which is a real concern....Like you said, \"so many options\"! Of course I'll be doing a new gain structure when I finally figure out the new set up!!
Getting back your last response and finding out I was using only one amp for the tops.Do you think it was a balanced system power wise? Do you think that's why I'm not happy with the sound, that the the DRPA may be set up right and I'm simply underpowered?..I wish I could \"beam\" you over here to check this out.
Thank you for your experiance, talent and time!!

Dra

I knew that you used 1 Xti, but for some reason ignored the fact that 600 + 600 = 1200 (rms) = 2400w amp to match. :oops: :oops:
the rating of the cab and the load that each present never changes, only the load that the amp sees by adding speakers.

So you are slightly under the 2x point, but overall the balance is a lot better than it was.

DRA

trshot

Dra,
can you recommend an amp that will allow me to run a two amp set up? One for the tops and one for the bottoms? You know, one's that I don't have to refinance the house for

Dra

This is about ideal. The first is cost reasonable, the second... not so much.

SRxxxxx
1) 2400w @ 4 (bridged)
or
1) 1200w @ 8 (stereo)

MRxxxxx
2) 2400w @ 4 (bridged)
or
1) 2400w @ 4 (stereo)

You either have to go with 3 amps or spend big bucks to go with 2.

DRA

trshot

Dra,

I'm excited to play with the amp config's and see what happens. You covered and helped me understand alot of issues in this thread. I'll be sure to check back and follow up.
Since I'm a drummer by trade, learning sound has been both fun and frustrating. I read alot of the info in this forum just to learn or discover new things. You and Gadget deserve alot of credit for your efforts here! Thanks again for such FASSSST responses..

Dra

T...
Email sent.

DRA

trshot

DRA



Thanks for the offer, I don't think it will work for me unless I use it for a mon amp,Your last response would work with the 4725's but I plan to use the 4732's I just bought. I plan on using the 2-CE's bridged to the subs and 2-XTI's bridged to the tops. correct me if I'm wrong. I'm running JRX112's (250w@8ohms) for mon's. The amp may be better suited for the mon's..Thoughts?



sr4732 -1200 cont @ 4ohm = 2400



mx528s-1200cont@ 4 ohms =2400

Dra

The amp is rated 475 @ 8 which is about perfect for the JRX112's. Not sure how I got stuck on the 4725's. Long thread I guess.

DRA

trshot

lol....well we did cover alot stuff in this thread, So I'll give you a pass :shock: ....How much do you want? When your ready let me know...