A push for Wave Guides

[Branwell]

For those of you that need a push to try wave-guides…..

For reference, in the past two years I’ve had active and active/passive systems configured in WWMTM, WWMT, WMTM, WMT and had them in ported, sealed, and in dipole configurations. Also had some ported line arrays….

Drivers used included Peerless 12” XLS, Eminence Kappa Pro 15lf-2, Seas W22, W18ex, SS18W/8540, 15M, PHL 1340, 1120, SS9900, Seas Millennium, Morel 110, North D28, G2, Newform 45” Ribbons, OW1, and a few I’ve probably forgotten.

Last summer I got a pair of BMS-4540ND compression tweeters with DDS I-90 Pro wave-guides. Also picked up a pair of 10” PHL extended midrange drivers.

I intended to set them up with the 15” bass drivers using a DEQX crossover, but being a compression tweeter and 10” mid, I had big time second doubts. Anyway, got them setup in temporary boxes and listened for a while. This was enough to convince me that I really should be getting some better boxes built…

The system came apart.…

….and for the last couple months, I rolled through all my “normal” configurations :Z while figuring the box thing out for the pro drivers ;x(

Yesterday, got the new boxes stuffed with the BMS and PHL drivers and spent a few hours on the crossover. Points ended up at 200hz and 1600hz. Slopes are 96db per octave.

I suppose the most controversial component in the speakers are the compression tweeters and wave guides.
So, how do they compare to the other tweeters mentioned?
There simply is no realistic comparison. The BMS not only has an order of magnitude more headroom, but it just plain sounds a lot more real. Cymbals, Triangles and instruments with a lot of air and shimmer are the best I’ve heard. Fantastic definition. They also excel with complex sounds such as brass and large orchestras.

The 10” midrange? Again, like the BMS, it just feels unlimited in headroom and never sounds strained. Female vocals never sound thin and male vocals project with great weight.

Anyway, for those of you that are tempted to try a wave-guide: I’d say go for it. The more even dispersion and extra headroom they provide at the bottom end do pay off.

For those of you thinking of trying a compression tweeter, some of them are pretty nasty, but I’d take a BMS with Digital EQ over any ribbon or 1” dome I’ve ever heard. 8)

If there is one thing this system has enforced in me, it’s that the more I think I know, the smaller and less interesting my world becomes.

B

Heres a photo of one of the speakers. Just need to round the edges and paint them.... :B

http://web.mac.com/bmcclory/iWeb/Audio%20Stuff/Photos_files/DSC01467.jpg

[JonMarsh]

Forward to the past? ;^) Or "go back" for the future?

Thanks for the update on your work and your comments. Is that a PHL 3002? What guided your choice of 1600 Hz for the mid to treble crossover?

Just for grins, I ordered a pair of the 4540ND. They should screw into the MCM waveguide... I've got some unmodified ones I can test. Should be interesting...

~Jon

[JoshK]

I am going to try a similar setup. I have a trio (would have been four if not for FedEx) of 95db Lambda 15tdx's, a pair of JBL 2123H 10" midranges and the DDS I-ENG90 wg's. I planned to order the BMS 4552ND CD's soon. (I have a DEQX too).

[JonMarsh]

I am going to try a similar setup. I have a trio (would have been four if not for FedEx) of 95db Lambda 15tdx's, a pair of JBL 2123H 10" midranges and the DDS I-ENG90 wg's. I planned to order the BMS 4552ND CD's soon. (I have a DEQX too).

You Got Gear, Josh! Been pondering if some day I should get a DEQX, too- depends on what kind of prototyping I can do with the DCX2496 and LspCAD Pro. Which version do you have? Gotta say that spending close to $4K does give me pause...

[Branwell]

Hi Jon,

On crossover points:
I looked at the measurements and used the tail of the BMS response as a low marker and then a few hundred hz prior to the cone break up of the PHL at the upper end. I then had the DEQX create a series of calibrations between those two points and listened while switching back and forth from the listening position via a laptop. Oh the luxury of technology ?. Ended up picking 1600hz because it sounded most real on a verity of material.

On the PHL:
It’s the 3431…

Graphs:
Here is a graph of a smoothed measurement the DEQX used to create the correction / crossover for the system. I took out the bass to make it clearer.
There are some diffraction artifacts visible, and what else is interesting, the mid needed no baffle step correction, just some general EQ….

http://web.mac.com/bmcclory/iWeb/Audio%20Stuff/Photos_files/BMSPHL.jpg

A couple of the PHL driver….

http://web.mac.com/bmcclory/iWeb/Audio%20Stuff/Photos_files/DSC01458.jpg

http://web.mac.com/bmcclory/iWeb/Audio%20Stuff/Photos_files/DSC01455.jpg

Josh,

A note on the DEQX.
Depending on how efficient your mids are, you might have to take a bunch of gain off the BMS. I ended up using a 10db L pad between the amp and the BMS so the Digital had less work to do. It also solved a slight hiss problem I was having by moving the noise floor down.

Another interesting experiment you can try.
If you want to see how much of a sound signature caps have, try putting one on the tweeter and then have the DEQX re measure and recalibrate. No caps definitely sound more transparent, more dynamic, and well, just better. I tried some Solens, Jensens paper in oil, Hovlands, North Crescendos and some interesting VTV silver in oils. They all where very distinct sounding.

Branwell

[cjd]

FWIW, I didn't find the DEQX to be superior to passives in exactly the same system despite a 30Hz room node it could sorta deal with on the fly. And it didn't seem any better than a different system with the DCX2496 - it lacked "environment" in playback (is that low level detail loss? That's my guess anyhow).

C

[Branwell]

Jon,

Not that you asked but...

I have a DEQX ( preamp version ) as well as a DCX2496 and can offer the following comments.

Overall, the DEQX sounds better than the DCX ( more transparent ), and if you just want to press a couple buttons and have a crossover, it’s the way to go.

On the other hand, the DCX is a lot more like creating a passive crossover. Its you who gets to determine the baffle step correction, phase around the crossover region etc.

As to the ultimate sounding crossover, with standard non troublesome drivers, the best crossover I’ve heard ( on the same drivers and cabinets where a DEQX was used ) was a passive using North components.

On drivers as troubled as the BMS in a wave guide, I don’t know. The Digital might have the edge because of the amount of correction needed.

Branwell

[JonMarsh]

Jon,

Not that you asked but...

I have a DEQX ( preamp version ) as well as a DCX2496 and can offer the following comments.

Overall, the DEQX sounds better than the DCX ( more transparent ), and if you just want to press a couple buttons and have a crossover, it’s the way to go.

On the other hand, the DCX is a lot more like creating a passive crossover. Its you who gets to determine the baffle step correction, phase around the crossover region etc.

As to the ultimate sounding crossover, with standard non troublesome drivers, the best crossover I’ve heard ( on the same drivers and cabinets where a DEQX was used ) was a passive using North components.

On drivers as troubled as the BMS in a wave guide, I don’t know. The Digital might have the edge because of the amount of correction needed.

Branwell

Thanks for the comments. I would have thought the DEQX would have similar flexibility, but I guess what you're saying is that you have to rely on the auto-calibrate function? Some of us like a stick shift...

[JonMarsh]

Ever seen this "JBL"? Not hard to guess who it's made by....

[Mark Seaton]

You Got Gear, Josh! Been pondering if some day I should get a DEQX, too- depends on what kind of prototyping I can do with the DCX2496 and LspCAD Pro. Which version do you have? Gotta say that spending close to $4K does give me pause...

Hey Jon,

With your tastes and interest in various crossovers, I think you should pause before plunking down $4k, and see if you should save a little more for the the 8x8 or 4x12 version of the Dolby-Lake processor. I'll be installing one in a rather over the top HT soon, and will have it on hand to familiarize myself with it soon. While the drag-n-drop layouts of the more common matrix processor like SoundWeb London, Symnet, etc. are a little easier to sort through, the filtering and graphic interface capabilities of the Lake are almost awe inspiring. The inclusion of an array of linear-phase filters with multiple variables add to the list of goodies. I have also read (still need to confirm) that you can generate filter transfer functions or similar in programs like MatLAB to execute all sorts of unique correction. Definitely a different tool than the DEQX, but something you should certainly check out. No tool is perfect, but this is one I have on my list to get after I climb a little further out of the money pit I created in starting a business in audio. :roll:

Nice to see someone with your crossover experience and capabilites exposing more DIYers to some adventures with horns and compression drivers. :T

[JonMarsh]

Thanks for the heads up, Mark, and I'll look into that.

Now, the funny thing is, one of the first speaker systems I ever built was a full Altec A7 replica, with the 500 Hz horns crossed over at 800 Hz. Done a few other things like that in the early 70's, including JBL acoustic lens based system in the late 70's. Drivers have changed quite a bit, and one of the more interesting things I heard at CES 2006 was Ayre's modified set of JBL K2-9800's.

We'll see how this experiment goes- shaping up to be a real "hybrid".

~Jon

[EspenE]

I am going to try a similar setup. I have a trio (would have been four if not for FedEx) of 95db Lambda 15tdx's, a pair of JBL 2123H 10" midranges and the DDS I-ENG90 wg's. I planned to order the BMS 4552ND CD's soon. (I have a DEQX too).

I also plan to try a similar setup. I have a pair of JBL 2226H and a pair of JBL 2123H, and a DCX2496 for crossover experiments (though in the end I like to build analog electronic crossovers with opamps).

I have a couple of questions:

1) Where did you source the DDS waveguides? I have not found any distributor in Europe, and DDS does not answer mails. (Have tried many times). Do you know any US distributor who want to sell/ship overseas?

2) Is the DDS screw- or bolt-mount? If bolt mount: what adapter did you use?

Thanks,

[Branwell]

Hello EspenE,

DDS Contact Info : DDS moved at some point in the not too distant past. Incase your contact info is not current, here is their website which has some info.

http://www.ddshorns.com/

On distributors : I got a pair of the DDS I-90s from here:

http://www.assistanceaudio.com/10_DDS.html

Would be worth asking if they will ship to Europe.

On mounting : The I-90 can be ordered with Screw or Bolt mounting.

Branwell

[JoshK]

Both usspeaker.com and assistanceaudio.com sell the DDS I-90. USSpeaker doesn't have it on their site, but they said they'd drop ship it for you if you request it.

I got the bolt on version, because I planned to order the 4552ND. The dude @ AA said that only the 4540 was screw on and the others were bolt on.

[EspenE]

Thanks, JoshK. I'll give them a mail. And good luck with your project!

[Branwell]

Josh,

I have the smaller 4540ND that screws into the I-90 and was wondering…..Once you get your project up and running and have had a chance to eval, would you be interested in doing a temporary swap. I’m thinking this would give you the opportunity to try the smaller BMS and I could try the larger?

Branwell

[JoshK]

Branwell, that seems doable. Although I got quite a few things on my platter at the moment and not sure when I am going to get those done.

[Ludvig]

Great job Branwell! It's always interesting with something that is breaking new ground. I'm fiddling around with a PHL 2460 at the moment to match with my 4540ND, but there are no baffles made yet.

Have you measured the off axis performance of the waveguide? The question is how "CD" it is and how I should weight almost perfect CD performance vs eventually lower HOM at high SPL when chosing between XT1086 and ENG 1-90

/Ludvig

[Branwell]

Hi Ludvig,

How CD are the DDS?. I don’t know enough to be able to answer that.
Have I measured them off axes? Yes, but don’t have the pictures with me. Could post some next week if your like.

Branwell

[Ludvig]

Could post some next week if your like.

It would be very kind.

/Ludvig