Bruce B
WBF Founding Member, Pro Audio Production Member
It would have to be to correct the FR. Harman doesn't know which room they are going in. Unless I've missed where they include a room calibration mic and correction software.
Intrigued by JBL M2 speaker system .... Opinions please ...
- Thread starter joeinid
- Start date
It would have to be to correct the FR. Harman doesn't know which room they are going in. Unless I've missed where they include a room calibration mic and correction software.
Let me rephrase, is the DSP being used in this case for the crossover, and the included room correction package, or is JBL using DSP to alter the basic response of the speaker itself? The online lit only refers to room correction software.
Tim
DSP used for active crossovers will change the off-axis of the speaker the same as a passive crossover. Room correction will not change the off-axis of the speaker.amirm said:
Passive and active crossovers (DSP) are used to create the basic response of the speaker. There is no such thing as a flat basic response of a driver let alone once you put it in a box and add a baffle.
Thank you sir! I'm a sucker for a hot horn speaker thread...
I agree, the Volti room with the Vittoras was excellent, I didn't hear their other room. And imo the Classic Audio speakers were the best that I heard at the show... not that I heard a great many rooms, but that room really sounded right to me.
That was the Event Horizon 210, shown by yours truly. It is based on a new enclosure type, the Manipulated Vortex Waveguide, which I'm using under license from the inventors. Glad you liked it!
We happened to be next to Volti (actually two rooms away; there was an unused room in between us). At one point we put on a Kodo drum track and cranked it a bit for about half a minute. I then turned it down because I knew we were breaking the show's SPL rules. A few seconds later Greg Roberts of Volti came running into our room asking if that was us. Yeah, I confessed. He said that at first he thought his subwoofer amp had gone nuts. Not bad from two rooms away, and we weren't anywhere near clipping the 30-watt OTL amp; we probably had another 6 dB to go.
To my ears, the crossover in the Event Horizon 210 wasn't done yet. My bad, I just barely got the speakers to the show. So if you noticed a little bit of cupped hands and a slight lack of top-octave energy, and maybe a slightly mid-forward tonal balance, good ears on your part, and that's all been fixed.
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I heard the Event Horizon, and was really impressed, but for some reason couldn't listen at length but wanted to go back later (didn't).
I thought it was up there with the four horn type systems that I really liked. Wasn't there long enough to notice niceties about the response. There were several horn systems that weren't so great.
The Event Horizon room didn't even look very well optimized.
I thought it was up there with the four horn type systems that I really liked. Wasn't there long enough to notice niceties about the response. There were several horn systems that weren't so great.
The Event Horizon room didn't even look very well optimized.
Bruce B
WBF Founding Member, Pro Audio Production Member
Next year, if you don't mind, please introduce yourself, as I really like to meet people that I've talked with on internet forums. Especially if they said something nice about my stuff!!
Good call!
We had two large speaker systems set up in that room... the four-piece Dream Maker LCS system got the preferred short-wall placement, with some breathing room behind the main speakers, while the Event Horizons got shoved against a side wall. Fortunately they worked pretty well there, but it certainly wasn't ideal.
No room treatment, and that was intentional - I like to show off that my designs do a decent job with the off-axis sound (a design goal that the team behind the JBL M2 would probably approve of). But the presentation could defiintely be improved with intelligent room treatment, which is not my area of expertise, so for next year's room I plan to seek out Jeff Hedback's advice. And, I plan to only show one system next year; juggling two in one room was a bit much.
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I did listen to the JBL M2's and they had promise but I think they could use some more dialing in and perhaps more break in of the drivers. Also heard the Kef LS50's with the 200wpc Hegel integrated amp fed by a Mytech DSD dac. Very nice sound and great little speakers for a small room. The sound in the big room with the Revel Salon 2's powered by Parasound JC-1's, JC2, and the Playback Designs MPS-5 was very nice as well. Sounding much larger than the Kef's as your would expect. We listened to lots of great DSD files thanks to Bruce.
Hello Tim
A friend of mine loaded the DSP and took some screen shots. Here is what it's doing. Any CD horn needs compensation beyond the mass break point of the compression driver diaphram. As you can see from the EQ they trade off some efficiency on the woofer to gain a bit more LF extension.
Hello Duke
The JBL dual diaphrams are unique. The VC wire in the 2216 woofer uses the special alloy to combat power compression. You can purchase the compression driver through JBL pro as it is used in several of the SR boxes and the Vertec systems. The waveguide and woofers are not for sale.
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Sorry, I had no idea that it was a speaker that was associated with one of our members. It was an "easter egg" as I just wandered into the room.
As Rob's screenshots show, the sound of the M2's is totally programmable. For the event last night, we tuned it to the ears of the folks who came before the show started. We did not sign off on it one way or the other 
. We did whatever they told us to change in the response curve.
Bruce, please come back and let's spend some quality time with them.
. We did whatever they told us to change in the response curve.Bruce, please come back and let's spend some quality time with them.
You can say that again! I read up on it a bit. The internal geometry is totally different from what I'd imagined. It has two donut-shaped diaphragms that squeeze together, in push-push, and the sound energy in the tiny airspace in between them is what gets funnelled out to the outside world. Conceptually, sort of like a compression-driver adaptation of Oskar Heil's approach.
On pages 244 and 245 of "Transducers", Earl Geddes describes a 6% nickel-copper alloy whose resistance changes very little with change in temperature. Nothing is ever a free lunch, and the addition of the nickel raises the resistivity of the copper, such that a thicker wire is needed to get the resistance back down to a useful value. Efficiency takes a hit due to the more massive wire. Of course the upside of the efficiency loss from the increased moving mass is improved bass extension, so the net result is a very good trade-off for a high-end home audio or studio monitor, and you also get very high power handling along with the virtual elimination of the primary thermal modulation mechanism.
That compression driver is very tempting. Heck, they all are. There's a part of me that's a bit skeptical of the waveguide, just because I can't envision how it avoids having significant diffractive effects, but not being an expert on horn/waveguide design I am also skeptical of my skepticism.
No problem, wouldn't expect you to know me, I haven't been spent a lot of time here, as my modest post count reveals.
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Hi Amir,
I am very interested in your findings and experimentation. Thank you in advance for your help!
I am very interested in your findings and experimentation. Thank you in advance for your help!
As Rob's screenshots show, the sound of the M2's is totally programmable. For the event last night, we tuned it to the ears of the folks who came before the show started. We did not sign off on it one way or the other
Bruce, please come back and let's spend some quality time with them.
Following maybe of interest to some.
Seems Linn have developed their active to finally be fully digital, which also includes DSP algorithm-tailoring to the room.
One reviewer tested away from boundaries and then right next to the wall, subjective results were positive when comparing both setups (the DSP setup-configuration is changed).
Price though is not cheap, think it was £50k as the fully digital active setup.
Cheers
Orb
I need to correct an erroneous assumption on my part, in post #74. The patented wire JBL uses in the voice coil of the woofer in the M2 has silicone rather than nickel as the alloy material, and according to Earl Geddes it works even better than the nickel-copper alloy he had previously applied for a patent on.
That waveguide is intriguing me more and more. It looks to me like the radiation pattern changes with angle, this because the waveguide's profile changes with angle... compare the path down one of the valleys to the path over one of the hills. Not that the pattern of other horns doesn't also change with angle, but I think the internal geometry goes through more deliberate variations here than in anything else I've seen. Obviously the team at JBL had reason to believe that was a good idea (assuming my armchair analysis is in the ballpark). If anyone has insight into what's really going on, and the rationale behind it, I'm all ears.
That waveguide is intriguing me more and more. It looks to me like the radiation pattern changes with angle, this because the waveguide's profile changes with angle... compare the path down one of the valleys to the path over one of the hills. Not that the pattern of other horns doesn't also change with angle, but I think the internal geometry goes through more deliberate variations here than in anything else I've seen. Obviously the team at JBL had reason to believe that was a good idea (assuming my armchair analysis is in the ballpark). If anyone has insight into what's really going on, and the rationale behind it, I'm all ears.
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Harman has a proprietary and patented waveguide design software that I think is used there. Prior to that it was used in the new generation Revel speakers. If you look at their waveguides, you see very odd things like a vertical crease! The ability to deform the waveguide and yet optimize it beyond any simple curve.
Hello Duke
I can understand your skepticism but frankly I think all this diffraction slot emphasis is not well placed on the next generation Bi-radials/Waveguides. If you look at a JBL 4430/35 measurement you can see the deep ripple in the response. Not so on the new horns and waveguides. I have first hand experience with the PT's where I used a PTH1010 as a replacement for a 2344 I was using in my active set-up.
The PTH1010 is a 1.5" 100X100 waveguide. To me it looks suspiciously like the M2 waveguide but the M2 has additional refinements. The PT waveguides all had a diffraction slot however it was nothing like the original first generation Bi-Radials. It's much more refined and does not have the ultra sharp transitions present in the original horns. I will attach a photo of the original horns used in the 4425/4430/35 the 2342/44. Compare that to the PTH1010 photo's very different transitions through the throat.
I will also attach a measurement of a throat-less large format driver on that waveguide. That is a sim as I have to make the actual networks but take a look at the voltage drive and lack of significant ripple in the measurement. That's with 1/12 octave smoothing ungated. The network is basic 18db slope, attenuation with a simple series filter to smooth out the upper octaves and single parallel notch to take out the 1-2K response peak.
Rob
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