Jbl 4365

[bubbleboy76]

Get an audio interface and a measurement mic. A small amp can also be of use. I use the Focusrite Scarlett Ii2i, there is a thread about it in Swedish Hififourm. Are you a member?

You can measure distance to sound source in Holmimpulse. Arta is another good free measurement program.

Linkwitz-Riley 24 dB is the way to go.

Mårten

I have REW and the Radioshack SPL Meter to start with. But maybe I will use my DBX rta-m microphone with this Focusrite-thing later on. Thanx for the tip.

I tried some times to be a member of hififorum, never succeded though!

[ivica]

Kind of explains why the compression-driver is recessed approximately that distance. I learned something new today

Hi,

You have to think that almost any kind of filter would introduce some kind of signal delays. So LF section of the filter would introduce some kind of the signal delay (driving LF driver). So a kind of the network delay has to be "compensated by the geometry".
Not to forget that each driver has to be 'modeled' as a kind of band-pass filter too.



Regards

ivica

[ivica]

Hi Ivica,

Are you able to provide a link to the thread where JMLC talks about this rule of thumb ?

I'd like to see if there is a formula ( hiding ) behind that "applied" constant .

Thanks

HI Erl_K,

May be can be started from here:
http://www.diyaudio.com/forums/multi...er-system.html

or even better from here:
http://nicolas.davidenko.perso.sfr.f...ragejmmlc.html

but I think there is English version somewhere too.

http://freerider.dyndns.org/anlage/LeCleach1.zip

http://freerider.dyndns.org/anlage/LeCleach2.zip

on the second link You can find the file: crossovers_JML.ppt where more explanation is.

http://freerider.dyndns.org/anlage/LeCleach.htm


But on the Internet can be find the whole JMLC presentation of his view over speakers filtering vision.

[bubbleboy76]

I started fiddling with the dbx driverack 260 today.

If I want to crossover at 800Hz with LR24db-slope, should I then set the high pass/lowpass crossover points to exactly 800Hz? Or should I set it like 790 and 810 and then the slopes starts going down and meeting a bit down? Or is the driverack doing this automatically, so I just have to enter the intersection-frequency, so to speak?

I don't have amplifier-channels enough yet, so I am just "dry-coding" the driverack for now.

[audiomagnate]

I started fiddling with the dbx driverack 260 today.

If I want to crossover at 800Hz with LR24db-slope, should I then set the high pass/lowpass crossover points to exactly 800Hz? Or should I set it like 790 and 810 and then the slopes starts going down and meeting a bit down? Or is the driverack doing this automatically, so I just have to enter the intersection-frequency, so to speak?

I don't have amplifier-channels enough yet, so I am just "dry-coding" the driverack for now.

You would set it at 800.

[Jonas_h]

As I wrote earlier there is no way of telling at what frequency and what slope to set it to. That depends on the natural response of the drivers. You probably need some HF-compensation filters for the CD as well.
You need measurements

[bubbleboy76]

As I wrote earlier there is no way of telling at what frequency and what slope to set it to. That depends on the natural response of the drivers. You probably need some HF-compensation filters for the CD as well.
You need measurements

what is "CD"?

I know, I will measure for sure!

[Jonas_h]

Compression driver

btw i am looking forward to your results. I have thought about doing The same for my next speaker purchase. But The M2's are a tempting choice as well!

[more10]

Or Constant Directivity.

[Goophy]

Goophy, if you are reading this, how did you connect to the 1501fe-element, did you reach it from behind the speaker-terminals on the backside?

If you haven't done the same already.
I unscrewed the 1501fe and ran wires through one of the bass ports.

[bubbleboy76]

If you haven't done the same already.
I unscrewed the 1501fe and ran wires through one of the bass ports.

Thanx, I finally got my measurement-rig working (DBX RTA-M mic, Focusrite 2i2 sound interface, Laptop with REW). So I will do the wiring tonight.

I added the DBX Driverack 260 to the signal-chain some days ago (still passive crossover, and only bypass in the 260). And I am a little bit disappointed with the "digital" sound it adds. Some naturalness is lost.

[bubbleboy76]

I added the DBX Driverack 260 to the signal-chain some days ago (still passive crossover, and only bypass in the 260). And I am a little bit disappointed with the "digital" sound it adds. Some naturalness is lost.

I take this back, after more testing I must say the 260 is very transparent.

Did the wiring today. Now the experiments with the crossover will begin!

[Mctwins]

I take this back, after more testing I must say the 260 is very transparent.

Did the wiring today. Now the experiments with the crossover will begin!

Hallo!

Glad that you took it back, I was thinking, what did he just write now. Didn't wanted to comment it before.

But, I still don't understand what you are trying to achive with the dbx260. Are you gonna remove the x-over in the speakers and use the 260 instead?

[bubbleboy76]

Hallo!

Glad that you took it back, I was thinking, what did he just write now. Didn't wanted to comment it before.

But, I still don't understand what you are trying to achive with the dbx260. Are you gonna remove the x-over in the speakers and use the 260 instead?

I never tried active crossover before, thats why I do it, for the fun of it. I also want to try to voice the speaker a little bit warmer, if possible. I want it too sound more tonally like my 4429-center. The 4429 has a little darker sound, with more bottom in male voices for example.

I use the 260 as a active crossover and EQ, bypassing the internal crossover.
Bi-amp.
2-way (I skip the UHF).
The initial SPL-curve is much flatter when I close the bassports, and it plays much deeper. So maybe I will go for closed box.

[Mctwins]

I never tried active crossover before, thats why I do it, for the fun of it. I also want to try to voice the speaker a little bit warmer, if possible. I want it too sound more tonally like my 4429-center. The 4429 has a little darker sound, with more bottom in male voices for example.

I use the 260 as a active crossover and EQ, bypassing the internal crossover.
Bi-amp.
2-way (I skip the UHF).
The initial SPL-curve is much flatter when I close the bassports, and it plays much deeper. So maybe I will go for closed box.

Ok, I understand about using the active x-over. Still don't understand why you remove the passive x-over in the speakers. You won't get any benificial improvment by removing the passive and trying to set an new settngs for the transducers with your own settings. You can use the prePEQ for setting the overall tone to your liking. I asume that you are bi-amping, you can still bi-amp the speakers with the 260 together with the passive x-over. My opinion, you are messing with the wrong speakers, a speaker that is allready tuned to perform the best. If you wan't to go with "true" bi-amping system then choose a speaker that dosen't have any passive x-overs, like the M2 or any other PA system.

I don't know how you are measureing to come to any conclusion for the best settings. If you are measurening in your room, then I say, good luck with that. You have to measure either in anechoic chamber or outdoor to set the x-over point and so on.

About your SPL curve and closed box, it has nothing to do with your speakers, it is all room dependent. You still don't know if the room modes is playing tricks for you here. This has to be measurerd (acoustic room measurement) and confirmed and treated before mixing with speakers x-over, closed-open bassports or bi-amping.

My 4429 has no dark sound.

I will hold my breath for the moment and see what you come up with.