Experiments with M2 horns.

[Don C]

I created my file from scratch in Audio Architect, and I noticed that the woofer/tweeter channel assignments came out the opposite of what is shown in the JBL provided (LA) Blu-80 file. It didn't bother me, I hadn't placed a singele wire yet when I noticed. I couldn't find a way to fix it in the crossover, it wouldn't let me change the "out" setting on the first filter. But I could have easily crossed the wires anywhere in the design after the crossover to make the two files match. I didn't though, I just wired my system the way it was drawn in AA, and it's fine.

[grumpy]

I was just happy that bringing BLU box configurations up and down caused no
nasty pops or clicks

Planning on using 1500AL's on the bottom so I believe a 4+ft3
effective volume for the bass section is what I'm looking at.
Someone has probably posted the M2 bass volume (I'm assuming
it's not the whole box), but I missed the 2216Nd order. I'll get
over it

[macaroonie]

Now that you chaps in the land of milk and honey are getting ready to slice up some wood may I take this opportunity to remind you of this interesting-outfit in Anaheim.
They do pre formed plywood sheets in curves , from memory up to 96" radius.
With a bit of imagination and luck you should be able to emulate the M2 front if that's your fancy.

http://www.aitwood.com/StoreFront.As...0%20degrees%29

They also have hard maple ply , a new one to me but sounds like it might be good stuff.

Also pre formed MDF components like large radius corners and so on.

Loads of interesting gear , if it was local I'd be down there in a hurry.

M

[srm51555]

Is there a place where one can learn more on the real life application side of things? This may just a thing of practice with LA also. Thanks, Scott

Thanks to Grumpy and DonC for the video idea and link. I eventually found what I needed on page 9 of http://www.bsstechsupport.com/public...on-network.pdf I didn't find it at first since I thought it was network connection document only. I also figured out that I need to select Operate and Online in LA to view live sounds. Since I'm running analog and need a high gain signal, Id like to run my cd player straight into the BSS BLU-100 and then use a EC-V to control the volume, essentially eliminating the preamp, any thoughts? Thanks, Scott

[Don C]

I think that you could make the BSS unit into a pre-amp. You would have to study the control panels section of the training, and you might want to add a break in box to get more sources. If you are handy, you could make a volume control for a lot less money than that wall panel, and it could look better too. I'm thinking of adding an external bass level control implemented with a simple pot connected to a control port, and linked to an equalizer gain control. It would duplicate the function of the woofer level controls that I had when I was using a four way active crossed speaker system. I was accustomed to having that control handy to fix up program material that lacks bass, and I miss it.

[grumpy]

Thanks Mac! Been awhile since I've poked at their web site.
They're darn close. Good way to shoot a day, just getting ideas

[macaroonie]

Thanks Mac! Been awhile since I've poked at their web site.
They're darn close. Good way to shoot a day, just getting ideas

I suppose that's how all those curved sides you see these days start out. It certainly opens up some possibilities to the home builder. Their half round forms could be useable in a 99000 way
Field report and pics obligatory.

Cheers Grumpy

[srm51555]

I think that you could make the BSS unit into a pre-amp. You would have to study the control panels section of the training, and you might want to add a break in box to get more sources. If you are handy, you could make a volume control for a lot less money than that wall panel, and it could look better too.

Thats probably a better idea, cheaper at least. I was hoping I would be able to run the pot over to my chair so I wouldn't have to get up as often. Anyone know the maximum length of wire you can wire a pot in, I think the run would be about 20 feet, if not i'll post the question on the BSS site and repot back. I'll probably also look into wiring a selector switch also since the BLU-100 has 12 inputs.

[Don C]

Sorry about the wall of text below. I've put more time in working on the EQ curves and learning about the process.
By trial and error, and some reading of the help files, I've learned that the REW software is not going to fill in a curve that needs a lot of gain added below the reference level to correct it. It's logic avoids filling in holes, but will do a better job of cutting off any peaks that go above the reference level. So it is not going to give you a big slope up at high frequencies to correct for a CD horn in the system. You will have to make that for yourself before letting REW make it's filter suggestions. It also doesn't seem to like making adjustments too close to the edge of the band you've selected to correct. So you must tell it to start working aa 500 hz, if you want it to start looking effective at 1K. You also have to tell REW not to make filters with more cut than 15db, to match the capabilities of the BSS. REW will make enormous filters boosting the signal and then counteract them with enormous filters in the same area cutting the signal, and the BSS can only do this to 15db max.
So my idea with this latest go-round was to equalize the speakers to as flat as I could get by them adjusting them manually, then to run the REW filter generator afterwards, and see what it gives me.
I hauled a speaker into the back yard for this , connecting them with 50 feet of speaker wire to the amp in its normal location in the house. They were hoisted 40 inches above the ground. I used a 4M USB extender and a second active 4M extender to make the microphone cable reach into the yard. The USB microphone wouldn't work at this distance until I added that active extender.
After driving the neighbors crazy with whooping noises for a while I got them EQ-ed pretty flat at 2 meters distance, straight in front of the speakers and 4.2 Ms gated. The two meters distance seems to be important, making them flat at only 1 meter makes them sound too dull if listening at longer distances. These filters are in the BSS output section. Then I measured a couple of feet off axis in each direction and made an average of these three gated curves. I let REW make an eq curve from that, and used these filters to replace the old JBL provided input section filters in the BSS. Note that the REW suggested curve includes a gentle slope downwards a high frequencies, that I've left in.
If you looked at the first response curve that I posted in this long thread, you notice that my preference is to have a lot of bass. Adjusting the speakers to measure flat on the bottom wasn't doing it for me, I want more. I have them pushed up pretty well at the bottom, we're talking 14db of boost at 20hz. The LE14s can deal with this without any issues at all. I've also put in a notch filter to kill a room mode that shows up at my favorite listening position. This is not new, I'd had something like this adjusted into these speakers by ear, all along. But it was blind, I didn't know the numbers. So the numbers surprised me, I had no idea that I had been listening to a curve like that. But this is what sounds best to me, and I'm keeping it this way.
After setting the speakers back up inside the house, the results are excellent. The treble is back, in a dramatic way. But with a more refined sound than before that is new. I can listen to any CD in my rather large collection and not hear anything that surprises me, except that I'm hearing more resolution and power than I'm used to.
I also got lucky in estate sale shopping this week, and bought 20 plus Audiophile CDs for one and two dollars each. Chesky, Audioquest, Reference Recordings, MFSL, a great find. So I'm listening to them. What I'm hearing is a sound just like what you would hear at a high end audio store or at a good room at the audio show. Maybe better. They image very well, throwing out an enormous sound field. I'm completely happy with this, and I'll be leaving them alone for a while. I'll have to start over of course, when the final cabinets are done, if ever.
I don't know if anyone cares about these response charts, I'm getting a little bored of posting them, they don't really describe the sound well. But here they are anyway, along with the BSS settings that were used to get them.

Output filters on the Horns:



Output filters on the Woofers:



Input Filters, made by REW.



Response curves
Red Curve, the average of three positions curve, outdoors, with only the horn output filters applied.
Blue curve: Also outdoors, after the REW generated input filters were applied. Only one sweep is shown here.
4.2 ms gated.

[1audiohack]

All this work and then taking the time to make sense of it and share it is indeed appreciated.

Thank you for doing it, especially if it is becoming tedious for you. I have been following silently and absorbing as I am sure are others and I thought it was high time to thank you for your efforts to share.

All the best,
Barry.

[Don C]

Dave's True Story: Sex without Bodies, and Dave's True Story: Unauthorized. Chesky Records CDs. Absolutely mesmerizing.

[grumpy]

All this work and then taking the time to make sense of it and share it is indeed appreciated.

+1

[Mr. Widget]

Yes, thanks Don! I can appreciate the pain it is to gather the info and post it trying to make it useful for others... I haven't worked on any DIY projects or the like in years, but from work I've done I the past I know what you're getting at.

If I decide to go the BSS route, I will certainly revisit this thread for the useful info it contains.

I haven't dug deeply into it so I may have missed your discussion of the 74Hz notch filter. I find it interesting as I am currently using a similar notch in my room. Mine is at 72Hz set to about -9dB. (Similar room dimensions?)

Also +1 on Dave's True Story! I'll have to check out these albums. I only have their self titled album, but it is quite good.


Widget

[bubbleboy76]

Thanks for sharing Don.

Are the horn output filters taken from the JBL M2 settings?

Which crossover-slope do you use (acoustical and electrical)?

[srm51555]

All this work and then taking the time to make sense of it and share it is indeed appreciated.

+2. Thanks for blazing the trail. I've never posted anything close to your extent, but can imagine it being a time vortex. Hopefully now I can find some 2451's so I can join the fun.