2432H and 2226h polarity

[Jonas_h]

I cannot seem to find the spec sheet for the 2432H compression driver. Does anyone know if it is "red => forward motion" or "black => forward motion"?

Another question... I have just received the 5641 enclosure (the 2226H driver in a 4507A enclosure), and can see by the spec sheet of the 2226h that black => forward.. Will this mean that JBL has wired the 2226h this way in the 5641 enclosure or have they switched polarity to follow the "standard"?

[stephane RAME]

http://www.jblpro.com/catalog/support/getfile.aspx?docid=241&doctype=3

Stéphane

[Eaulive]

I cannot seem to find the spec sheet for the 2432H compression driver. Does anyone know if it is "red => forward motion" or "black => forward motion"?

http://www.jblproservice.com/pdf/Theatre%20Series/4722-HF.pdf

I guess it's a positive transducer, if I interpret this specsheet correctly

[Jonas_h]

Thakns for the answers. On the 4722-HF terminals, it says "EIA", so I guess this verifies that it is positive.

The 2226H is negative, but I dont how it is wired in the 5641 enclosure. In Stephanes document, the 5671, which uses the 5641 LF enclosure, is listed as negative, so I guess the 5641 is negative as well.

Do you know how to actually measure and verify this?

[Eaulive]

Can you find the spec sheet for this model?

Anyways, with a small battery at the cabinet terminals, you can check the polarity. Then you must assume that JBL wired the rest of the components properly for the system to work correctly.
This you can confirm with the service spec sheet.

This also could be useful: http://www.jblpro.com/catalog/support/getfile.aspx?docid=478&doctype=3

[Jonas_h]

Can you find the spec sheet for this model?

Anyways, with a small battery at the cabinet terminals, you can check the polarity. Then you must assume that JBL wired the rest of the components properly for the system to work correctly.
This you can confirm with the service spec sheet.

This also could be useful: http://www.jblpro.com/catalog/support/getfile.aspx?docid=478&doctype=3

Ok that is weird.. In Stephane's document, the 5671 is described as "negative" but in the document above it says positive? Am I reading it wrong?

[Eaulive]

Ok that is weird.. In Stephane's document, the 5671 is described as "negative" but in the document above it says positive? Am I reading it wrong?

Well, what it says is that there's no reverse connection on any component.
In some settings, it call for reversal of the mid driver for example, in order to restore phase. In this particular setup, all cabinets should be connected + on red.

Now maybe INSIDE the woofer box, the 2226 could be reversed.

Don't confuse driver wiring and cabinet wiring.

[Mctwins]

That's correct. Just connect it as labeled on the cabinet and you are fine. Have excactly the same cabinet. + to + and - to -.

Thanks

[Jonas_h]

I have hooked my system up as described on the cabinets (+ to + and - to - on LF/HF). When optimizing the x-over and having the delays set, measurements showed that the best results was achieved when the polarity on the HF was reversed. After speaking to JBL, they mentioned that this is very common and is done in passive networks often too.

The system sounds great and I've achieved my goals. :)

[badman]

I have hooked my system up as described on the cabinets (+ to + and - to - on LF/HF). When optimizing the x-over and having the delays set, measurements showed that the best results was achieved when the polarity on the HF was reversed. After speaking to JBL, they mentioned that this is very common and is done in passive networks often too.

The system sounds great and I've achieved my goals. :)

Reversed from proper polarity, in a good design (read- coherent summation) is pretty easy to hear with A/Bs.

[Mctwins]

Hi
Just for my understanding, have you reversed the polarity on the high freq driver just for the measurements or have you left it reversed.

Could you just clarify what you see in your measurements?

Thanks

[Eaulive]

I have hooked my system up as described on the cabinets (+ to + and - to - on LF/HF). When optimizing the x-over and having the delays set, measurements showed that the best results was achieved when the polarity on the HF was reversed. After speaking to JBL, they mentioned that this is very common and is done in passive networks often too.

The system sounds great and I've achieved my goals. :)

BUT, is the 2226 connected BLACK on + inside the cabinet? IE, Black connector of 2226 on positive lead of cabinet?

[Mctwins]

Hi
Eaulive.... excactely what I think it is but I haven't lookt inside the cabinet. But + is + and - is - for me on the terminal and I connect it accordingly to that.
Thanks

[Jonas_h]

I left it reversed... My procedure:

- Measure impulse response on both drivers individually
- Set delay on HF so top of impulse matches
- Measure ffreq-response of both drivers playing together.
- This measurement showed a null around x-over.
- Switched polarity and the freq response was perfect along the x-over.
Se image below.

http://dl.dropbox.com/u/10759510/ForumPics/JBLCinemaV1/both_raw_and_optimized.jpg

[Mctwins]

Hi
Sorry Jonas, but I don't understand what you have been doing here.

What is your delay time?

What is your crossoverpoints and slopes?

How do you know if it is not at room issue that cause this suckout?

How does your impulse responses looks like?

How is your phaseshift at crossover point?

Why are you only measure from 80 Hz to 8000 Hz?

I see it like this, to acheive proper measurement on the loudspeaker it schould be outdoor or anechoic chamber.

Thanks

[Jonas_h]

Hi
Sorry Jonas, but I don't understand what you have been doing here.

What is your delay time?

What is your crossoverpoints and slopes?

How do you know if it is not at room issue that cause this suckout?

How does your impulse responses looks like?

How is your phaseshift at crossover point?

Why are you only measure from 80 Hz to 8000 Hz?

I see it like this, to acheive proper measurement on the loudspeaker it schould be outdoor or anechoic chamber.

Thanks

I don't have the numbers/measurements right here.. But the delay time is set on the HF so it matched the impulse response measurement of the LF in the listening position. I would think that this is the way to look at it?

I use 24db/oct BW slopes, and set the crossover at 800hz. I'm only measuring from 80 to 8khz because the measurements are regarding the crossover-point. I measured the LF alone, and there is no suckout in the range 600-900hz... If a room suckout was present, this would show in the measurement of the LF alone. The suckout is only present when both drivers are playing together. I have setup everything from information I could find on various guides on the Internet, so suggestions are always welcome.

[Mctwins]

Hi

It is not correct to measure from the listening position, if you ask me.

What did you set the delay time 50sec or 50msec or 2 hours?

What processor do you have?

Thanks

[Mctwins]

Hi
Another question, don't you get out of phase in this setup, meaning that the HF is reversed and the LF is normal.
Thanks

[Mctwins]

Hi
Could you show a picture how you have aligned the LF with HF. You can measure the distance between LF to HF physically and then calculate the delay time. For ex. I have between LF to MF/HF 14cm and it is 0,40ms adjusted in the LF.
Thanks

[Jonas_h]

Sorry for the late reply. I didn't get any notification e-mails.

In regards to the out of phase issue when I revert the polarity, then I just followed recommendations from the store I bought the speakers at and guides around the internet.

When I set the delay, I do not measure the distance between the LF/HF.. I do a measurement with software of both drivers individually and measure them impulse response.. I can then compare the response ofthe LF and HF and compute the difference in time (i.e. when the signal arrives at the microphone). This must be the correct delay to put in. I think the delay is around 60msec. The HF is tilted a bit.

Why would you not measure in the listening position? The important thing is to have the LF and HF sound arrive at the same time for the listener - not at a microphone right in front of the speakers. (Thats my theory :))

[Mctwins]

Hi
According to Rane witch I belive is true and it is the same for the dbx setting for the delay time between the drivers.

Read this manual
http://www.rane.com/pdf/old/ac24man.pdf

Between my LF to the MF is 14cm and then I divide this number with 34,5 cm it will get 0,406ms and this number corresponds to the settings in dbx for my speakers.

according to this formula

331,4+0,6Tc

Tc= temp in degress Celsius
m= meter
s= seconds

if I calculate your 60ms I will get,

34,5cm x 60ms = 2070cm, this can't be correct. If you now have it 2 meters apart between LF and HF then it is correct.

About measureing in room how do you know if it is not a suckout in your listening position, when you have the polarity in phase. When you have the HF in reverse you get a straight line.
Now, what is correct here?

Thanks

[Jonas_h]

I was a little too fast on the keyboard. Tje delay i use is around 0.6ms

[Mctwins]

Hi
Aha, now it is better.

According to dbx260 setting for 4622 bi-amp(same as 4722) it say's 0,75ms in the LF section and they have not reversed the polarity.

The crossover settings in dbx260 is, and I asume, is done in anechioc conditions.

That goes for the PEQ as well.

What DSP do you have? If you don't have the dbx260 it may give you totally differen't results.

Have you read the link?
Thanks

[1audiohack]

Hi Jonas;

If your testing software will do impulse measurements it should be capable of also showing you individual driver polarity.

If that notch shows up with all drivers polarity posative, you may be off just a tic on your delays.

[Jonas_h]

Hello,

I have just examined the 4722 settings on the DSI amp presets, and it says that the HF should be reversed... I have recently find out, that one of my 2226H drivers are defective, so it will take a while before I get on with the measurements :(

[wrager]

I need clarity on wiring my 4622's. The polarity issue is very confusing, further complicated by going active, bi-amp. For the 4509, I assume the positve amp side is connected to the red input on the 4509 (2x2035). Not sure how the 2035's are wired within the cab. Now for the 2430's ( I am actually using 2450SL's), is positive connected to the black input? I am using the Crown DSi amps. Thanks!!!

[Jonas_h]

I was tired of the confusion, so I bought a polarity tester. Google 'cricket polarity'.

[wrager]

So Jonas, please explain how you wired the cabinet and also the CD. It would be great if you could help me with this! I have the same amps.

[Jonas_h]

Hi Wrager.

To be honest, I don't remember how I wired them and I don't have the speakers anymore to check :/ As far as I remember, the 2226H enclosure was forward cone motion when positive voltage to black.

But you should really just go ahead and ghet one of these: http://www.sweetwater.com/store/detail/Cricket
Very nice tool when calibrating the theater (also for surrounds and subs. Nice to know that what you are doing is the correct thing).

EDIT: I don't use the DSi amps. I used the BSS London Soundweb and Crown CTs amps. I only used the DSi settings to look at the settings.