Settings PA+

Mctwins

Hi,
I am new here and I have recently purchase a DBX driverack PA+ and will arrive in a couple of days. I have JBL 3731 Cinema Screen Array with McIntosh system and running in monoblock and bi-amping configuration. I have a some questions?

Is there any recommended settings for these speakers regarding crossover settings and alignment delays. I coulden't find any information about this anywhere or even at JBLpros website. There is for 3632 and 3632(triamp) with JBL DSC260A.

Does DBX have this settings for JBL 3731?

Thanks

Gadget

Ya.. your right...Short of calling JBL ...(and good luck with that...)
I did find crossover points...
http://www.jblpro.com/catalog/support/g ... &doctype=3
perhaps you did as well?

That shows crossover points of 350hz and 1.2KHZ

It also shows a 3dB down point of 40 hz...so, if you have the power, set a 40hz HPF @BW18

I would go with LR24 or BW24 filters

Measure the distance from the cone of the sub to the cones of the MF section... using (.885ms/foot actual) round off to 1ms/foot if you like...and the location of the diaphragm of the horn...and using the distance measured back up the horn and mids to match the woofer. So if it's 12 inches difference, get as close as you can to 1 ms ...not sure what the finest increment is on the DRPA+...

Now you need to find out if the drivers are reverse wound or standard...see this post:
viewtopic.php?f=60&t=2255

The 2226H is smack in the middle of the "Black" terminal is positive group.. the others are not on the list..

Do you have the measurement mic?

Gadget

Mctwins

Hi
I got the PA+ today and have installed it. I do have Behringer EMC8000 mic. I have also set the crossover HPF 25Hz LR12 and LPF 355Hz LR24 to HPF 450 Hz LR24, just test it here for now. I will try the HPF 40Hz BW18.

I don't follow you regarding measureing the speakers cones, you mean the front baffle to the cone, the depth or the lenght between the cones.

I have also heard that one can measure the time alignment with a step response, do you know how it works?

I will ask further question as times pass by, I just got started.
Thanks

Gadget

I have also set the crossover HPF 25Hz LR12

:shock: :shock: :shock:

You WILL damage those cones with that low of a HPF... those cabs are 3db down @ 40hz and 10dB down @ 30hz..those are older cabs (are they not) that weren't really meant to be true subwoofers.
g

Mctwins

Hi
Now I don't understand, to calm you down I have set the HPF to 40Hz with BW12.
According to recommended signal setting for DCS260A in the Cinema Sound System Manual for the 3632(bi-amp) and 3632(tri-amp), it say's;

Bi-amp: HPF 31,1Hz BW12 and

Tri-amp: HPF 25Hz LR12

and also they have the same data in freq response as the 3731. The speakers are one month old and brand new so I don't know what you mean by old cabs.
Please explain?

Here is a measurement before with DBX 223XL(yellow line) and after with PA+(green line).

I would like to go with the HPF 30Hz BW12 if it is ok with you.

Thanks

Dennis

I assume the green trace (PA+) includes the 40Hz HPF. If so, please post a trace with no HPF in place.

Dennis

Mctwins

Hi
Good question, Dennis, I will do that and let me get back too you.
Thanks

Mctwins

Hi, Here is the difference between the ruler flat out and 40Hz BW12.

The green line is without any crossover settings.
Thanks

Dennis

It looks like 30Hz should be fine....maybe 35 to be safe. Assuming the traces are accurate. Actually, it looks like it is Highpassed internally already.

Dennis

Mctwins

Hi
The model number is 5641, bass is 2226H mounted in 4507A LF enclosure and the bass don't have any passive crossover as far as I now, can't find any Technical Manual as same as for the 4509 LF encosure.
I still don't understand why it is dangerous to to set the HPF to 25Hz, what could really happen, technically speaking.

Could someone please give me a answer.
Thanks

Gadget

If the cab is designed properly it will offer resistance to the linear movement of the cone to help prevent the speaker cone from coming in contact with the mechanical stops...(read that the voice coil SLAMS into the back plate of the magnet :shock: It's called linear over excrusion and causes a clacking sound just before it destroys itself....) Dennis thinks that 30 hz is ok,(and I believe that he is probably correct) but consider this... that speaker is from the 70's..early 80's era if I'm not mistaken...(and as such may suffer from age...)the designs were less than stellar ..especially bass wise. Also, @ 10dB down @ 30 hz it would take 100 times the power to make that 30 hz equal to the AVERAGE of the speakers response.. and I'm betting that the low cabs have a peak (unlike the response chart posted on the link) @ 60, and 100hz that are well...significant.

everyone would like to get 25 hz performance from their speakers...small, lighter, and lower are pretty much mutually exclusive terms...in reality, to ACTUALLY get 25 hz performance it usually takes huge arrays, or some REALLY innovative designs. Check this out:
http://www.danleysoundlabs.com/tapped_h ... L=TH%20812
This beast has 12 :shock: :shock: long excrusion woofers and even IT cannot reach 25 hz ... not even with 16,000 watts!... in a theater sub however, this one will:
http://www.danleysoundlabs.com/tapped_h ... L=DTS%2020
but look at the size of it.. It accomplishes the goal with extremely long tapped horn designs.

If you try to get 25 hz from that woofer...you WILL destroy it! That is my opinion, AND if you leave the HPF @ you'll still going to be well over 10dB down @ even 30hz...it's just not possible with that design..

Dennis, back to you...
G

Mctwins

Hi
Now I understand what you mean, due to lack of passive crossover I have to use active crossover to maximize the output of the amplifier, so the bass is within it's working limits.

The closest I could find about the setting for this enclosure and with this voice coil is Cinema 5000 serie (5671), 32Hz LR24. I have set mine at 30Hz LR24 for the moment.

So what I have to do is I have to put, for an example, one or two 4641 subwoofer to compensate for the low freq with an additional amplifier.

Can I use the PA+ and run Low for the 4641, Mid to the bass 3731, High for the passive M/HF 3731?

This subwoofer goes down 22Hz -3dB with EQ.
Thanks

Gadget

Good I didn't mean to come across as "freaking out" ...I was being "dramatic" to make a point.. I often do to inject some levity...it doesn't always work. As you can see from my further explanation it is possible to damage the drivers. From helping others we have discovered that a BW18/24 slope is more often used for HPF than any other slope.

High for the passive M/HF 3731?

Yes the DRPA will do that but I'm not sure what you mean here? Are you using a passive crossover on the MF/HF section?
G

Mctwins

Hi

What I mean about passive is that it have already a passive crossover on the MF/HF.
You can order it like this from JBL. This is assembled at the factory. You can get it for tri-amp as well, then it is called 3731T.

Thanks

Dennis

Gadget wrote:

but consider this... that speaker is from the 70's..early 80's era if I'm not mistaken...(and as such may suffer from age...)the designs were less than stellar G

Commenting on this requires me to use my nonexistant memory but here goes...I believe you are thinking of JBL 2225s which are 400W rated speakers that I used a lot of in the 80s. In the late 80s or early 90s, ElectroVoice came out with the EVX series of low frequency drivers (EVX150, EVX180, etc) that were marketed as "1000W" speakers but were actually 600W continuous and 1000W program. The EVX180s became very popular and if I remember correctly, Dave selected them for use in the Rat subs.

JBL came out with a line of low frequency drivers as competition to the EVX series which included the 2226 and I think that puts them early 90s. I have never seen a 2226 with a "black" positive post but I also read the same info on their website that you posted one time, indicating otherwise. I believe the 2225s did have black positive.

2226s were included in many JBL speakers for years, up to the time that VRX and SRX700 hit the shelves (with new 800W drivers). They may still be in use for other enclosures but I don't really know.

All of this is kind of OT, but hey, you got me started.

Dennis

Gadget

You know I love to push your buttons Dennis... :twisted:

Do you think he is really going to get any real/useful 22-30hz performance form either of those bins?
G

Dennis

Gadget wrote:

Do you think he is really going to get any real/useful 22-30hz performance form either of those bins?
G

Hell no but I thought we were talking "technically correct".

Gadget

And you would be 100% technically correct.. as always Thank you Dennis..that is why you are such an asset to this site...
thank you my friend, I hope some day I will be able to come meet with you in person!
G

Dennis

Gadget wrote:

And you would be 100% technically correct.. as always Thank you Dennis..that is why you are such an asset to this site...
thank you my friend, I hope some day I will be able to come meet with you in person!
G

Aw, shucks

Gadget

Now my home theater is a horse of a different color.. I have the Sunfire Home theater sub;
http://www.sunfire.com/productdetail.asp?id=9
Can you say :shock: :shock: :shock:

If you have any furniture that has loose joints, if the floor is noisy, if the light fixtures are not well made...EVERYTHING will rattle, buzz, vibrate...and drive you nuts! That is with a 1 cubic foot speaker that has 2, 10" (one passive one active) speakers that WILL go down to 18hz... Two Infinity RS 1.0 front and some proprietary custom center and rear speakers that are something else.. 8)

"If the house is a rockin" it's likely a movie...
G

Mctwins

Sorry for the late reply,

I have set it like this for now;

HPF 40Hz BW24, LPF 355Hz LR24, HPF 355Hz LR24

Very satisfied with the sound!

Thanks for great info.

Mctwins

Here is a link with some pictures and measurements, can't post pictures here. The size is to big.

http://www.audioheritage.org/vbulletin/showthread.php?28924-JBL-3731-and-McIntosh

Thanks

Gadget

WOW :shock: :shock: :shock: that is impressive! That room treatment is really something...I would love to try and mix in
that room (recording studio stuff...) VERY impressive setup. Looks like you have a "labour of love" going with that... you must be single...or... have a VERY understanding significant other

Myself I only have a pair of Infinity RS2, a Sunfire MkVII http://www.stereotimes.com/speak010202.shtml and a trio of Dayton studio monitors for surround and CTR channel...The EMIT tweeters in the RS2's are super sweet and the Sunfire provides LF extension to 18hz (3dB down) believe me when I say that ANYTHING in the building that is in disrepair WILL rattle, and things mysteriously move around the room and fall off the walls if not properly fastened down...

As for posting pictures... simply get a PHOTOBUCKET account and they will host your pics...


then paste the image file into the post...
(that's my studio/jam room...)

Where is this system anyway?

Thanks for the posts!
G

Mctwins

Thanks, glad you liked it.
Just wanted to show my room so you know what I am talking about. There is some studios who use these treatments. Really, it works!
I don't play any instruments and I leave it to people who know this things, I am just enjoying listening to music.

Singel or not I have room to spare, no problems here whith the significant other.

If you jump on a aeroplane and head towards skandinavia you are very welcome to pay a visit.

Those sunfire subwoofers looks interesting, I will check it out. There is no rattling problems in my room.
Thanks

Mctwins

Hi all,

Gadget, I know that you don't like JBL but I wasen't satisfied with the active subwoofer they had on the market, to expensive contra the performance they do.

I have added two JBL Cinema 4641 Subs to my system with Crown Macro-tech MA 5000i amp to drive them and it sounds great even if it is not fully tuned in yet. :shock:

Some DBXPA+ queastions??

I have connected like this;
MA 5000i amp to 4641 to Low Left output/mono
Mono McIntosh 2xMC252 to main bass module JBL 3731 to left/right Mid output
Mono McIntosh 2xMC275 to M/T module JBL 3731 to left/right High output

Crossover setting is done accordingly to specs for the subs and 3731. Don't worry, those 4641 goes down two 25Hz and have set it at Highpass 25Hz BW24.

I have done custom setting for the Low, Mid and High but when I perform the auto-level it won't pass the(pinknoice) Low output. I have also connect one XLR cable from DBXPA+ to the MA 5000i. MA 5000i is Y-linked in input and speakercable as in stereo left and right to subs. Can't figured out what setting I schould use. I have set it on DBX as three way fullrange and I choose bi-amp for the High and Mid outputs and mono for the Low outputs.

It seems to be working when I see the input/output meters on DBXPA+, but here comes the strange part, schould the Low levelmeters been showing left/right levelmeter or only one.

Schould I choose for the Low output as stereo or mono or do you guys have some other ideas????????

Thanks

Gadget

Maybe if tell us what you set up.. like this:

Wizard setup: 2X5

Sub:
HPF

---

Lpf

---

gain---

Mid:
HPF

---

LPF

---

gain--

High:
HPF:

---

gain--

I can't make heads nor tales of what you have set up.

If you have selected a 2x5 then only one of the sub outputs should show level...
G

Mctwins

Hi
Sorry for that, I forgott to mention it. It was around midnight when I wrote this.
It is 2x5 wizard and the low is set for mono sub.

Low Left/mono output 4641 Subs
Hpass 25Hz BW24
Lpass 80Hz LR24

Here i have one XLR from DBX to y-linked MA 5000i. Amp outputs to each subs.

Mid Left/right output
Hpass 80Hz LR24 3731 Subs,
Lpass 355Hz LR24

High, Left/right output
Hpass 355Hz LR24 3731 M/T(passive)
Lpass out

No gain on the crossover for the moment. In this setup both of the meters on the subs output is showing, strange. :?

Hope this is more understanderble.

Thanks

Mctwins

Hi

I have done some test.

In the setup I choose bi-amp mode for main speaker in this case 3731 Mid to bass and high to M/T. Then I choose monosub for 4641 subs. I get 2x5 config. After this it goes to auto-level but it dosen't level the subs only mid and high.

I still have indication on both low output meters on DBX. When I do left/right balance from my preamp it has no effect on left/right output from DBX, only input and output from the Mid/High works.

I doesen't matter if I choose mono dual or stereo linked, please explain the difference. Input is in stereo.

I also tested from right output to my crown amp in stereo(no y-linked) still the config in DBX is monosub. The same thing happens with the balance senario from preamp.

I would like to have on my DBX tri-amp config, can't find it on any wizard setting or user settings or whatever, does not exsist.

Thanks

Gadget

Hmmmm

In the setup I choose bi-amp mode for main speaker in this case 3731 Mid to bass and high to M/T. Then I choose monosub for 4641 subs. I get 2x5 config. After this it goes to auto-level but it dosen't level the subs only mid and high.

I have no idea why it doesn't do the auto level for the subs... personally I don't use the auto level. I think it was an addition to the DRPA to decrease the number of calls from newbies that don't know that you need to balance the outputs so that you get the same sound pressure level out of the low mid and high sections...(or mids and hi's when bi-amping) I think they put the auto level in the wrong spot..at least for my taste... I would think that you set up in the wizard THEN set the crossovers and HPF/LPF THEN gain structure THEN level...but perhaps that's just me...

I still have indication on both low output meters on DBX. When I do left/right balance from my preamp it has no effect on left/right output from DBX, only input and output from the Mid/High works.

I doesen't matter if I choose mono dual or stereo linked, please explain the difference. Input is in stereo.

Did you ever verify that there is actually signal coming out of the right low output when you choose 2x5 config? I could'nt discern from your writing whether you had tested for that...

I would like to have on my DBX tri-amp config, can't find it on any wizard setting or user settings or whatever, does not exsist.

You ARE trying a triamp config the way you have it set up...The Driverack 260 simply defines the configs as 1x2/2x2/2x3/2x4/2x5 etc. but the DRPA looks at them (they dumbie it down I guess :? ) as (2x2) stereo fullrange (2X3) stereo fullrange tops with subs (2x5) bi-amp tops and mono subs... etc. I don't know what they were thinking again and I think it has caused a great deal of confusion

The setup looks fine...have you set up any PEQ's yet?
G

Mctwins

Hi
Ok, I see.

I have 2x5 (bi-amp, monosub) but I have connected bal cable left/right from lows to crown amp in stereo. actually I have signal in both left and right from DBX in mono sub. It looks like it sending out signals on both channel in mono sub so when use balance from my preamp left/right it dosen't follow. I will test using it in stereo sub and see if it follows.

The label on the backpanel of the lowoutput saying left/mono is then incorrect.
But still what does dual mono or stereo linked means in GEQ?????????? because, I have to choose one or the other in the auto level wizard. I have tested both and I see no difference between these settings, it dosen't change anything.

Please explain the difference between these two settings????

I will test the PEQ later on I have to fix this first and also set the subs in the right position in my room.

Thanks

Mctwins

Hi
I have tested with stereo sub and now it follows the balance from preamp left/right. You have to have both XLR cables from low output DBXPA+ to amplifier wheather you are using monosub or stereosub.
That's it.

I still don't understand what the meaning of using dualmono or stereolinked GEQ in wizard setup????????

Totally useless as I see it.

Gadget, please explain this technical error.

Thanks