The compression driver horn in the SRX does seem to only go to 1200Hz, even with a compression driver with a 4" voice coil. I guess the crossover is correct for the horn, but I think one should use a bigger horn and cross the compression driver lower. I was just using the PA speakers as examples to try to understand how a JBL CMCD 8" might sound like. Any input the CMCD would be nice. Right now I am thinking about using either a hornloaded Fane 8M between 120Hz-300Hz, or a 1" WE 555 lookalike, or cross the JA6681B lower to 250Hz and use it with a 12" JBL 2204H low freq driver.
I was working all night, and now I am done with both sides of a wooden 1.5m long, 75cm diameter Goto horn. I will glue them together soon, fix a mounting plate and then enjoy some sweet horn sounds with the JA6681B... tomorrow.
I did some more trials with channel upper midrange in a Avantgarde Trio tweeter horn. It adds a little more ohmph! than the 6 times more expensive Beyma TPL-150. The 1" in a small horn blends in much better with the 2" Radian 750-8. The Beyma TPL-150 made me think an upper midrange channel was not needed, because I could not really hear much difference, at least not when using the Radian 2" compression driver in a 40x40 cm horn from 450Hz up to 7kHz. Guess I will save the TPL-150 for another project, like the bass AMT project. I was sure classics like the Avantgarde Trio was out of date, and could use new ideas. And it does, but not sure the AMT was the best. It might work later, in a bigger room, bigger back chamber, in a bigger horn, I don't know yet. I need to live with it a few years more.
I was working all night, and now I am done with both sides of a wooden 1.5m long, 75cm diameter Goto horn. I will glue them together soon, fix a mounting plate and then enjoy some sweet horn sounds with the JA6681B... tomorrow.
I did some more trials with channel upper midrange in a Avantgarde Trio tweeter horn. It adds a little more ohmph! than the 6 times more expensive Beyma TPL-150. The 1" in a small horn blends in much better with the 2" Radian 750-8. The Beyma TPL-150 made me think an upper midrange channel was not needed, because I could not really hear much difference, at least not when using the Radian 2" compression driver in a 40x40 cm horn from 450Hz up to 7kHz. Guess I will save the TPL-150 for another project, like the bass AMT project. I was sure classics like the Avantgarde Trio was out of date, and could use new ideas. And it does, but not sure the AMT was the best. It might work later, in a bigger room, bigger back chamber, in a bigger horn, I don't know yet. I need to live with it a few years more.
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I got more things to do than to reply to your misunderstood
view of what I comumicated. Telling me that I am not intrested in
replying is kind of rude.
Sorry but this is getting ridiculous.
Do you really think you need to show us how to do proper PWT measurements?
I am in this hobby for over 30 Years and Dietmar who did the measurements even longer.
Dietmar has plenty time, passion, knowledge, skills and equipment. There is no other person
that I know of who is more productive when it comes to this hobby.
I suggested that the K33/Atlas driver was essentially a WE555 and that
it mus be possible to get the same results in the bass to mid department and Dietmar got right at it.
Within a few weeks he had modified 4 different K55 drivers to finally get this excellent result out of that little sucker.
Anything he did to the driver was documented and backed with valid measurements even showing distortion figures.
My whole argument here is that there is a cheaper, easier and better way to achieve what we want from a JA6681b on the Azura.
1. In my experience 200-300hz crossover point is not easy to work with and a dedicated sub woofer wouldn't even go as high.
2The Yamaha is not loading this region with enough authority as reported earlier.
3. Beaming is so bad that not even two people can enjoy good heights
4. JA6681 still needs a tweeter for absolute heights anyway even sitting in the sweet spot
5. It does not sound as open as a good CD horn from about 1000hz up.
I have not owned an Azura horn but it is not much different to a regular tractrix.
Here is an excellent explanation that John Hasqin gave as a reply on Audio Asylum years back.
He discribes the problem of those kind of horns which I fully agree with.
On my screen I see some funny characters between the text but I am to
buisy to take them out:
"
What I personally feel like contributes the most to beaming is using too large a horn for accomplishing the task at hand. A larger horn in my experience did not have better pattern control for the following reasons: Since the larger horn is trying to be used below the Fs of the driver, it behaves like a direct radiator with a high pass filter on the bottom frequencies. This happens because the tractrix is too short to properly load the sound wave fronts at the lower frequencies, you can’t cram a quarter wavelength sound wave into a horn that thinks it’s an eighth sized horn, depth wise. Mouth size does not matter as much as horn depth does here. Because the lower frequencies are not loaded, your control goes to hell on the bottom end and beams. In, addition in the case of a 2” driver with a horn of this size, the horn only loads approximately from Fs to 2200Hz. What you end up with is discontinuities on both ends of the frequency extremes, not a good thing. John you are correct in stating the high frequencies do beam somewhat, that is the physics of the situation and can not be changed. You would need a very, very small throat to get any loading much above 5kHz, smaller than 1”. What I find to help limit the perception of beaming is using the right sized horn for the job. When I design my horns I have some ratios and other rules of thumb that accurately predicts where the tractrix will “unload” the sound wave front given a certain horn flare and driver resonance. An example is the tractrix horn I designed for the Radian 475. I use a 380Hz tractrix and with the help of the driver’s resonance, 530Hz, I get nice strong output starting from 575Hz. Since the 475 is a 1” horn it loads the high frequencies to 4300Hz or so, above that it behaves as a direct radiator. What you get is completely horn loading and control from the critical mid range to 4300Hz. Above 4300Hz off axis you only hear a softening of the high frequencies as you move out of the sweet spot. However, from 575Hz to 4300Hz there is virtually no beaming and much less perceived difference in SPL outside the sweet spot because this whole bandwidth is being acoustically coupled to the air “properly”. When you get a horn and driver designed correctly like this the field of depth and imaging are incredible to say the least. Properly loading the sound wave front is everything and if you make too large a horn and have slop on the bottom, your results will not be optimal. I hope I have been able to convey what and why Bruce and I believe that large horns are not the “answer”. Thanks much, this has been a very interesting thread that has shed light to areas that needed to be discussed.
JLH"
Radian, what you are arguing here has nothing to do with what we "discussed" together above, which was only focused on midbass compression driver, and how a 2" Atlas compression driver could be better in this range than a 4" or 8" more modern (and costly, and with far more R&D behind it) compression driver.
The measurement you posted as a proof does not mean a thing if it is not backed up by at least *some* details (abs SPL, input level, tube characteristics, measurement procedure, etc.) that you are clearly not able to provide here.
The measurement you posted as a proof does not mean a thing if it is not backed up by at least *some* details (abs SPL, input level, tube characteristics, measurement procedure, etc.) that you are clearly not able to provide here.
I have no experience with the CMCDs, but I know someone who has: he bought a pair of SRX738 to replace a two way with a 15" and a 2"/4" compression driver on a CD horn.
He is quite happy with the result (although he replaced the filter with an active setup, and also replaced the box...). I can ask him some specific measurements if you want.
Regarding the SRX and PT horns, I have been using the SRX down to 1kHz, and the PT down to 1.2kHz with good success.
The limiting factor with this king of horn is more the directivity matching than the loading itself. These two units are more waveguides than real horn: they are not very deep, and not have a really marked "loading" frequency...
The biggest problem when using these horn down to their horizontal directivity control limit is that you typically loose vertical control in the first octave of their range...
Regarding tractrix horns (which Azura horns are *not* by the way), their directivity control is of course far from constant, but it is at least very smooth (much smoother than any CD horn, including OS). In my experience it also has a well controlled zone that is nearly constant directivity around 60° in the frequency range between 5xF and 15xF (F being the flare rate).
So for example with a 400Hz tractrix horn that would be the 2kHz-6kHz range.
Quite a narrow range, but that does not mean it cannot be used lower at least one octave, if the woofer below it is small enough to have a similar polar pattern at 1kHz...
I can finally compare the 2" Radian 750-8 (760PB?) with the JA6681B in this smaller horn. No Goto horn yet. Even with a 2" horn the JA6681B is noticeably more musical. A more dry sound in a way. Tougher. If Radian is Dwayne "The Rock" Johnson, then the JA6681B is Marlon Brando.
Very impressive. The Avantgarde Trio tweeter with a Beyma 1" adds something nice at 3800Hz to 7000Hz, that is lacking without. The Radian could do this better, but an extra 1" compression driver in a small horn was still better. I bet that another JA6681B would sound even better. I can hear what JLH meant with "acting like a direct radiator." above 4300Hz. This is about how the Avantgarde Trio is crossed.
I don't hear much difference on 500Hz and 250Hz high pass. This would require a bigger horn, I guess. Or my 100uF protection cap is in the way.
I added also a picture of a Goto S-150, or very similar, which I am building. This is not a very popular horn in these forums, and some opinions are quite negative, but I doubt many have tried them. If not for the JA6681B, then for the modded Atlas.
What I would like is his personal opinion of 150Hz-1000Hz hornloaded compression drivers like a modded Atlas VS. CMCD 8" for home use.
I would be very impressed if he has experience of this.
Very impressive. The Avantgarde Trio tweeter with a Beyma 1" adds something nice at 3800Hz to 7000Hz, that is lacking without. The Radian could do this better, but an extra 1" compression driver in a small horn was still better. I bet that another JA6681B would sound even better. I can hear what JLH meant with "acting like a direct radiator." above 4300Hz. This is about how the Avantgarde Trio is crossed.
I don't hear much difference on 500Hz and 250Hz high pass. This would require a bigger horn, I guess. Or my 100uF protection cap is in the way.
I added also a picture of a Goto S-150, or very similar, which I am building. This is not a very popular horn in these forums, and some opinions are quite negative, but I doubt many have tried them. If not for the JA6681B, then for the modded Atlas.
What I would like is his personal opinion of 150Hz-1000Hz hornloaded compression drivers like a modded Atlas VS. CMCD 8" for home use.
I would be very impressed if he has experience of this.Attachments
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A big one
I have a 100cm diameter Le Cléac'h which terminated at 90 degrees which I will put the FS100W n and measure. I also am currently building a 16Hz concrete bass horn for an 18" driver but i may build some 50Hz 4 sided Le Cléac'h to sit above the concrete ULF channel.
Yes, the split is something of an annoyance, but it's better than you might expect, and being into heretical ideas, I turn them vertically, which changes things considerably in terms of what you hear as a stereo image. For the better.
It was either this or else building myself a horn, as many others have been doing. But that would force havoc in my "to do" list, and it might cause the planet to become imbalanced finally causing catastrophe and the earth's axis to wobble uncontrollably. You do understand?
It was either this or else building myself a horn, as many others have been doing. But that would force havoc in my "to do" list, and it might cause the planet to become imbalanced finally causing catastrophe and the earth's axis to wobble uncontrollably. You do understand?
I don't have any "inherent harshness" whatsoever. Seriously.
No need to bounce anything. If you set it up so that one cell is totally on axis and then the other faces in a direction where you do *not* want highs going, then stuff the back of the horn (lightly) with cotton or polyester batting. The proper amount will merely attenuate the highs above some frequency (say ~5kHz.) but permit the lower frequencies through unabated. A whole lot depends on the specifics of your room as to if you need this trick or not.
It works very nicely on the other multicell horns, like the 1003 for example.
I take no responsibility for "climate change"...
_-_-
No need to bounce anything. If you set it up so that one cell is totally on axis and then the other faces in a direction where you do *not* want highs going, then stuff the back of the horn (lightly) with cotton or polyester batting. The proper amount will merely attenuate the highs above some frequency (say ~5kHz.) but permit the lower frequencies through unabated. A whole lot depends on the specifics of your room as to if you need this trick or not.
It works very nicely on the other multicell horns, like the 1003 for example.
I take no responsibility for "climate change"...
_-_-
Well, no I don't do that.
Corking it up, as you say would be a mistake since that will make the situation in the throat (which is a monster flare in any multicell) into a foobar situation. The reflections would not make for a good result.
What I was saying is that one *could* set the two cell horn up with absorbency in some or (in my case one) cell... I don't.
If ur sitting down, then one of the two horns, the lower is more or less on axis, but not if ur sitting back a bit... the room depth is 33 feet. So, if ur nearfield (huge soundstage) you become closer to on axis for the lower horn. Standing you get the same effect, but the upper horn more, and sitting tall midway back you are a bit center axis of the point between the two horns. The response differs mainly above 10kHz as measured. So, yes it is not completely uniform in that respect. Yes, it is audible. But no I don't really care that much, since I can chose to listen where I want, and can re-aim the horns if that matters.
The idea is just that you don't want to kill the lower mid output in favor of not bouncing highs off a surface that you don't want to bounce highs! The size of the horns mouth is essential to getting down in frequency, so omitting cells (like in the case of a 1003 for example) also would raise the F3 point.
What btw, is a "smoother type driver"?
I've never measured a driver with flatter response...
_-_-
Corking it up, as you say would be a mistake since that will make the situation in the throat (which is a monster flare in any multicell) into a foobar situation. The reflections would not make for a good result.
What I was saying is that one *could* set the two cell horn up with absorbency in some or (in my case one) cell... I don't.
If ur sitting down, then one of the two horns, the lower is more or less on axis, but not if ur sitting back a bit... the room depth is 33 feet. So, if ur nearfield (huge soundstage) you become closer to on axis for the lower horn. Standing you get the same effect, but the upper horn more, and sitting tall midway back you are a bit center axis of the point between the two horns. The response differs mainly above 10kHz as measured. So, yes it is not completely uniform in that respect. Yes, it is audible. But no I don't really care that much, since I can chose to listen where I want, and can re-aim the horns if that matters.
The idea is just that you don't want to kill the lower mid output in favor of not bouncing highs off a surface that you don't want to bounce highs! The size of the horns mouth is essential to getting down in frequency, so omitting cells (like in the case of a 1003 for example) also would raise the F3 point.
What btw, is a "smoother type driver"?
I've never measured a driver with flatter response...
_-_-