Brilliant track with Eno's synth arpeggios and the Edge playing the Infinite Guitar.
It's a shame the band lost 'it' after POP.
U2 became a commercial hit machine and Bono transformed from a spiritual rebel to a money-grabber and member of the global elite.
It's a shame the band lost 'it' after POP.
U2 became a commercial hit machine and Bono transformed from a spiritual rebel to a money-grabber and member of the global elite.
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This is my latest creation. If anyone wants to critique it, I'm all ears. One of the things I am proud about is the crossover versus speaker placement. The distance from Tweeter center to lowest woofer center vs crossover point of 300hz equates being 1.29X higher than KA=2.I have spent time, into developing my PPSL, in order to provide better FR than I've shown in the past. If all is consistent with my simulations, I should be able to completely remove the Null of the PPSL and at the very least, will easily be able to cross at 300hz or higher, where, there is no discrepancy on headroom through the crossband. The Horizontal polar transition from Horn to woofer section is wide to wider, and at 300hz we are still in the modal region of the room where such a transition can make sense. By squeezing another set of woofers in to play, the horn is at my desired ear height and headroom of the woofer section on one channel is handled by 4076sqcm of accumulated Sd. I have proven that there is enough headroom even at a 200hz steep crossing, by measuring thd closely at the compression drivers exit, horn removed but ignore that for now lol. When I simulate my TMM in Vituixcad, the nulls or lack there of, on the vertical axis are very encouraging.
The Sources are modelled as having no Directivity, crossed at 300hz LR24.... With the actual directivity of the horns and cabinets, the polar will not look like above... it will look... even better?
Grok "For a cylindrical source at ka = 2... the -3 dB point occurs at approximately ±45° off-axis, resulting in a total beamwidth of 90°"
Somewhere down the line I came to the conclusion that a nearfield monitor should not reach more directivty than ka=2 at crossover. 1.29x over the frequency [needed for ka=2] isn't bad for what is essentially a TMM design. ~200hz down, the two rows of woofers are within 1/4WL. The horn can potentially be crossed as low as 200hz in a domestic setting in my opinion. For KA=2 the crossover point would need to reach ~232hz, which I think it can do. I think 250hz is also a happy median between 300hz which is safe place for the horns headroom, and 200hz which is a safe place for virtually perfect summing. It is my opinion that low crossovers sound best, but this is a matter of preference. I also listen at 1meter so this is also unorthodox for many, and even more for a system that is this big.
The first iteration was a success according to my listening test, though people found things to criticize, that were valid. The main thing was FR of the crossing woofer and whether or not enough headroom truly was there, to allow a crossing at 200hz. I had already personally considered things satisfactory by listening test but I do want to show all pretty measurements with little room for technical criticism as it seems that my peers encourage it. A 300hz Xo puts me through the door with flying colors. To improve the FR of the woofers in the slot I have found 2 ways. Shape and Damping.
I think there is a lot of potential for this design, there should be a good summing through out and with so much headroom and the low xover, the woofer section performs mostly as a single acoustical axis thanks to playing within 1/4WL center to center spacing. It also eliminates another amp/dsp. I don't think I could squeeze any more headroom in so gracefully. If all the woofers were identical they could all share cabin space and a vent but having the two different styled woofers in the mix has its own perks. Qes is low for each driver, slightly lower for the 15".
I am trying to join the >2mm club, Seems to be the crude and most logical goal post. This design will be called "The Hulk" having massive power (Headroom and LF extension) as well as a genius scientist (Generally well performing Dispersion worthy of nearfield use).
Its not perfect there's still room for improvement but for me its obviously the journey. As for creating something that hasn't been seen before, horns mated to PPSL are not very common. PPSL in TMM form, I have not seen done yet outside of myself.
I think I created my version of the JBL 4722 and have a large group of people to thank for their contributions to the project. 😊 Maybe it will be up and running... one day 😂
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Other systems that I like have similar build but I think with my Design I can steer away from using a vent. The large amount of active surface area used should help mate the woofer section to the highly efficient horn. I like to say the PPSL is the shortest 4th order bandpass one could build. Its also cool to call it a synergy bass horn.... because of all the synergy, thats happening.
I am thinking to run the sets of woofers in parallel for the 6db increase in electrical sensitivity along with All drivers working together within 1/4WL adds up to something like +12db of sensitivity total each channel, and then +15db in Stereo.
I am thinking to run the sets of woofers in parallel for the 6db increase in electrical sensitivity along with All drivers working together within 1/4WL adds up to something like +12db of sensitivity total each channel, and then +15db in Stereo.
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..and this little piggy cried 'well, who's this then?'
I'm speaking in general terms about speaker measurements, so to be honest, I have no idea which part was taken as sour grapes. It's a fact that measuring/ABX testing speakers in a non anechoic environment leaves a lot of room for bias (probably unless you're using something like a Klippel system), right? I'm not badmouthing JBL or anything—in fact, most of my speakers have been JBLs for decades!
I was taking the mono vs stereo. If you look at Toole's papers that mono testing goes back to long before he was at JBL. So when he set-up the lab that particular issue had already been decided. Actually he tested both mono and stereo and landed on mono. It's explained in this paper and goes back to 1985. The only issue I saw about JBL was the speculation about the BBC dip which I felt was unfounded hence Speculation.
The whole idea that they are stacking the deck is again speculation. I know a couple of people personally who have been in the room and participated in the testing and they were surprised when the curtain was pulled back and the speakers revealed.
To me you are questioning the veracity of the research which has been peer reviewed.
We all have opinions and you are entitled to yours.
Rob 🙂
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The psychoacoustic details that are supported by trends of the studied, is where the meat is at for me.
If it takes 2-3 cycles to statistically perceive pitch then this is what I see. [Grok data is quoted] "200 ms RT60—20 Hz (50 ms cycle), 100-150 ms perception, 50-100 ms to RT60; 10 kHz (0.1 ms), 0.2-0.3 ms, 199.7 ms to RT60"
If it takes 2-3 cycles to statistically perceive pitch then this is what I see. [Grok data is quoted] "200 ms RT60—20 Hz (50 ms cycle), 100-150 ms perception, 50-100 ms to RT60; 10 kHz (0.1 ms), 0.2-0.3 ms, 199.7 ms to RT60"
Over six years now, and we are still waiting for "pretty measurements" of a satisfactory system..
Fortunately, you don't feel the peer pressure from technical criticism 🙂
I’ve read that paper many times myself, but as far as I recall, it didn’t contain a rational explanation for why they chose mono. Considering that stereo playback is overwhelmingly the mainstream, the fact that they deliberately chose mono for the listening test gives me the impression of an arbitrary bias that favors JBL. You could call that speculation and leave it at that, but I do think there’s a certain logic to it.
A fair number of audiophiles actually say that mono sounds better than stereo, but the likelihood that those people are horn speaker users is quite high. There's no way someone like that would be a B&W user, and I don’t think that’s entirely unrelated.
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The thing is, testing in mono is standard accepted by the industry, and stereo does not matter to judge the speaker itself, as the difference is the setup in the room, not the speaker. JBL did not invent that, that is standard bussiness practice since long before the paper from 1985 and has not been disapproved scientificly. If you disagree, you can make your case on scientific base.
And ABX testing is (subjective) testing for personal taste, not objective. The main thing here is that you don't get bias by seeing what speaker is playing so you judge only with your ears. A sighted test (the one where you see what speaker is playing) is proven to be very sensitive to bias by the view.
If you want a scientific measurment of a speaker then anchionic or semi anchionic (like Kippel NSF) testing is what you need. But that does not tell you what you like, it tells what the speaker does objectivly. Both types of tests have their advantages and disadvantages and goals.
And ABX testing is (subjective) testing for personal taste, not objective. The main thing here is that you don't get bias by seeing what speaker is playing so you judge only with your ears. A sighted test (the one where you see what speaker is playing) is proven to be very sensitive to bias by the view.
If you want a scientific measurment of a speaker then anchionic or semi anchionic (like Kippel NSF) testing is what you need. But that does not tell you what you like, it tells what the speaker does objectivly. Both types of tests have their advantages and disadvantages and goals.
With synergy, you mean all these nasty slot resonances? 😱😎 Together with the way too low X-over you may get true synergy 🤔
I think you might be misunderstanding me or you might not have read the papers we are talking about, but of course I have no objection at all to measuring speakers in mono.
What I said was; when it comes to evaluating speakers subjectively through listening tests, if the goal is to conduct statistical research in a typical listening room, then naturally, it should be done in stereo, which reflects the standard listening environment. All I'm saying is that deliberately conducting such tests in mono undermines the validity of the research as a scientific study.
Let me ask you the opposite—when you go to an audio shop to choose speakers, do you have them switch to mono before? There might be a few people out there who do that, but it's certainly not the norm.
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That is not true, that is what i want to say. You don't judge only the speaker while doing that, but the whole setup inclusive the room. By keeping it mono you focus more on the speaker.
The final test before buying could be stereo (preferable in your room), but not for ABX testing.
I honestly have a hard time understanding why you think a different approach should be used between the ABX test and the final judgment when evaluating speakers in a domestic listening environment. Could you explain your reasoning? Using mono to evaluate speakers while eliminating the issue of the phantom center seems just as meaningless as conducting a listening test in an anechoic chamber to eliminate the influence of the room. If there’s a fundamental flaw in this logic, I’d appreciate it if you could point it out.
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Better?
There's no way to achieve image widening effects or spatial placement of instruments with a mono signal.
Stereo does a much better job, but even that has its limitations.
Toole touches on this in his book as well.
As far as I know, the research he references in his book was conducted using stereo setups.
(hence the brief exploration to surround systems in his book)
The flaw is that speakers as well as the room are part of the total sound.
Even if the on-axis response of different loudspeakers is the same, they WILL sound totally different depending on how strong their directivity is.
With that also comes any other issues like mismatch in directivity, diffraction issues and that kind of stuff.
This is very evident in a poorly treated room.
In that case any person, even with little interest in audio, will hear the difference between an (almost) monopole vs a speaker that's strongly beaming.
Guess what? Those are exactly the techniques being used at airports, trainstations, churches and that kind of places.
Also because of masking effects the sound you get from a mono source vs stereo is completely different.
There is no way people can turn that off in their brains.
Yes this is the driving force. I was speaking of...
Top row shows EQ only fix, Bottom Row shows Damping only fix, Below is eq mixed with damping.
The thing is resonances were never a problem the first slow design. The little things that showed up in measurements were masked by the room. Below you can see slot resonances kick 100hz and up. Its not
Indoors it begins to be hidden by room reverberation.
Both of those measurements are without a crossover. A crossover would attenuate further improve the response, in particular the low pass at 200hz
The redesigned Slot should have even better performance. The lack of perpendicular walls really does a number on the slot resonance. The 1/2wl rear wall reflection created null. has been pushed up to almost 600hz. This is 3x high than needed for a 200hz xo and almost 1.5x higher than needed for a 300hz XO using sharp LR filters.here is a 300hz LR 4th order with one peak filter to take out main resonance, for demonstration
The XO for the horn+driver is still arguably fine at 200hz. I have shown the THD without the horn, taken with the voltage needed for headroom, with the mic as close as possible to the exit before clipping. I apologize for not being more technical but I will do better in the future. I really needed to take notes when taking measurements. These measurements reflect voltage at headroom level SPL with the mic close enough just to miss clipping and I presume some kind of high pass, most likely a 200hz 48db LR. This is the most intimate way to check THD as a horn skews the results.
A 300hz crossover, if only shown for technical correctness, is not a too low XO over, the driver is made for it and the horn is big enough for it. Will I still use it crossed at 200hz? Probably. It sounds amazing why wouldn't I? In particular at 1meter listening, because I can't go over 95db average thus and peaks will not likely go past 110db. In my past test of the first configuration I could not find too much to gripe about... thats when we had the discussion about subjective effects of THD. Regardless of the THD reading with the horn attached it is now obvious the driver is not being pushed into xlim. Now, the question is of subjective analysis of THD, to which I say, good luck. I have proven that the driver isn't in trouble of over excursion and that is all that really needed to be sorted.
The flaw that I cannot fix on my own is Docali horn that is as big as I want it to be. Maybe one day. I will pray...
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