Yeah I guess that is a fair statement. And if one goes with the Al Neo version it will take the Be version as an upgrade if the safer lower cost route shows it is a soiund one likes personally. Read that the the Neo motor is the same for Al and Be. Is that the consensus.
Trouble for me is I have a very good direct driver system at present and my target is to beat that. Perhaps we are all much in that position
Looks like the new diaphragm gives a,very nice roll off.Did some measurements of the Radian 745 NEO/beryllium today. Here's what I have so far:
This measurement was taken with no crossover or equalization…just the driver on the Azurahorn AH-425. Drive level is arbitrary.
Below it appears with an overlay of the regular 745 driver, with ferrite magnet and aluminum diaphragm.
Indeed. It is interesting to compare with the charts on post #9320 where the Truextant diaphragm in a JBL driver yields a similar roll off. Nice.
Many thanks to Gary for posting these and sharing listening impressions.
Pierre
Those graphs of the earlier aluminum ceramic driver look like they still have the 16khz resonant peak in them. That driver would have a real problem being flattened and giving a smooth top end and this was what I was talking about earlier, that peak is not musical in nature but a resonant problem with the combination of driver and diaphragm. Try and notch out that much resonant information and by the time you are done you have lost the top octave of useable range.
With the Be model you could at least use a slope in the network to flatten the top two octaves without having a large peak in the upper response curve. That to me is a major advantage and it looks like the mechanical resonant problem has been taken care of. It would however be interesting to see the Be driver with an aluminum diaphragm to see how much is just the difference between the breakup modes of the two different materials in the top octave.
With the Be model you could at least use a slope in the network to flatten the top two octaves without having a large peak in the upper response curve. That to me is a major advantage and it looks like the mechanical resonant problem has been taken care of. It would however be interesting to see the Be driver with an aluminum diaphragm to see how much is just the difference between the breakup modes of the two different materials in the top octave.
It does work from my end; I looked around on the site to make sure before posting the link. Doggone web browsers…I have no idea.
I am sending you a PM with Martin's email address.
There is a dip around 2 - 3 kHz that is not on the ceramic/Al driver which appears better at 8 - 10 kHz just looking at the graph. Or is this spurious
Thought the Neo driver for the Al Neo would take the Be diaphragm as a replacement and is the same driver. I think there are new Be diaphragms retrofittable for at least, most of the range.
Any body got a different take on this.
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Boldname,
I am going to assume for right now with no evidence that if you took the graph of the Be driver and went out past 20khz about 22khz or close you will again start to see some diaphragm breakup in the response curve like you are seeing at 16khz with the al diaphragm. The graph just shifts to the right with the beryllium. This also shifts those nasty areas up out of the pass band while the 16khz is right in the top of the band.
I am going to assume for right now with no evidence that if you took the graph of the Be driver and went out past 20khz about 22khz or close you will again start to see some diaphragm breakup in the response curve like you are seeing at 16khz with the al diaphragm. The graph just shifts to the right with the beryllium. This also shifts those nasty areas up out of the pass band while the 16khz is right in the top of the band.
It would be good to see some other tests esp pulse and step tests to see how the stored energy dissipates for Be and Al with the Neo driver.
I wonder at what dB level the Be and Al begin to close up a bit. So often when a Be direct driver is brought out it is often unremarkable as it is almost academic ,unless it audibly modulates with the lower frequencies. The enforced treble roll off by the horn geometry is often a great saviour
The HF breakups are not a single resonance, but a group of chaotic modes spanning most of an octave. A notch filter would not be effective, and I doubt that DSP could correct it either. Remember, both the horn and phase plug rely on uniform velocity across the entire diaphragm to operate correctly; some phase plugs suppress the first diaphragm mode by careful spacing of the slits, but have no effect on higher-order modes.
The narrowing directivity of the LeCleac'h can be exploited by listening to them off-axis, but I found that only slightly off-axis was desirable, maybe about 5 degrees or so. I aimed them at a point about 1 foot/30cm in front of the listener; you could see about half of the throat of the horn from the listening position.
Many readers may think that the hassle of supertweeter isn't worth it; well, the tradeoff is the lower limit of the MF/HF horn. Are you OK with a crossover between 1 to 1.5 kHz? That's what small-format demands. That, in turn, either implies a mid horn 40"/1 meter across, or 10 to 12-inch direct-radiators.
In the Summa loudspeaker, Dr. Geddes utilizes the first mode of his 15" driver as part of the 950 Hz electroacoustic lowpass filter for the woofer, and takes the small-format Mylar-film compression driver just slightly below the lowest recommended crossover frequency. So a small-format compression driver can be combined with a 15" direct-radiator, it's just a path I didn't want to go down myself. I wanted a bit more spectral room between the LF and MF/HF, and this almost forces using large-format compression drivers, or the driver selection mentioned in the previous paragraph.
Boldname, you mentioned being satisfied with your direct radiator system. That's how I feel about the Ariels. I've had them for 20 years now, and still like them better than anything I heard at the RMAF show, or the CES in Las Vegas. There were one or two speakers at the show were about equals, but I was very pleased to listen to my own system after the show. For the last three years, my RMAF guests have liked it as well.
The main driver for the new loudspeaker is owning direct-heated triode amplifiers, which have power outputs in the 3 to 20-watt range. I am not going back to transistors, in Class A, Class AB, or Class D. 20 watts is adequate for the 92 dB/meter/watt Ariels, but only adequate. More headroom would be nice, but not at the expense of the quality I already have. That has been the primary goal all along.
Well, it turns out that a true 92 dB/meter/watt is pretty close to the upper bound of direct-radiator tweeters. You can get slightly more, but only just a little bit. The Ariel II would have been only slightly more efficient, and I'm not even sure modern drivers are any better than what I was using twenty years ago.
So the search has been for a horn that doesn't sound like a horn, but retains horn dynamics and vividness of tone colors. I'm not talking about always-there, additive coloration, but the capability of playing tone colors when they're present in the source.
I should mention that Gary Dahl has very critical ears; he finds the sound of most high-end equipment unsuited for classical music. I can only agree. Most of it mangles beyond recognition the sound of live symphony orchestra, to the point where most recordings are unlistenable and not enjoyable at all. Unlike the claim relentlessly pushed in the magazines and audiophile websites, mainstream high-end equipment isn't "accurate" in any sense, it is grotesquely inaccurate, and has the same relation to reality that a horror movie does to the real world. Based on what I hear in the hifi shops, RMAF, and the CES, less than 5% of the equipment on the market is suitable for music of acoustic origin. I enjoy the social aspects of the shows (very much), but the sound in most of the rooms is horrific, far worse than a table radio or car stereo. I have no idea why the taste in the high-end is so debased.
It also means I can't honestly answer queries about "what does this or that sound like" because my tastes don't accord with most of the industry. Gary Dahl, Gary Pimm, John Atwood and I share similar tastes, but I have no idea what most audiophiles enjoy. I've sat alongside audiophiles with checklists of subjective qualities, carefully ticking each box as they listen to a room at the RMAF, but to me it's either good or bad, with not much in between.
The narrowing directivity of the LeCleac'h can be exploited by listening to them off-axis, but I found that only slightly off-axis was desirable, maybe about 5 degrees or so. I aimed them at a point about 1 foot/30cm in front of the listener; you could see about half of the throat of the horn from the listening position.
Many readers may think that the hassle of supertweeter isn't worth it; well, the tradeoff is the lower limit of the MF/HF horn. Are you OK with a crossover between 1 to 1.5 kHz? That's what small-format demands. That, in turn, either implies a mid horn 40"/1 meter across, or 10 to 12-inch direct-radiators.
In the Summa loudspeaker, Dr. Geddes utilizes the first mode of his 15" driver as part of the 950 Hz electroacoustic lowpass filter for the woofer, and takes the small-format Mylar-film compression driver just slightly below the lowest recommended crossover frequency. So a small-format compression driver can be combined with a 15" direct-radiator, it's just a path I didn't want to go down myself. I wanted a bit more spectral room between the LF and MF/HF, and this almost forces using large-format compression drivers, or the driver selection mentioned in the previous paragraph.
Boldname, you mentioned being satisfied with your direct radiator system. That's how I feel about the Ariels. I've had them for 20 years now, and still like them better than anything I heard at the RMAF show, or the CES in Las Vegas. There were one or two speakers at the show were about equals, but I was very pleased to listen to my own system after the show. For the last three years, my RMAF guests have liked it as well.
The main driver for the new loudspeaker is owning direct-heated triode amplifiers, which have power outputs in the 3 to 20-watt range. I am not going back to transistors, in Class A, Class AB, or Class D. 20 watts is adequate for the 92 dB/meter/watt Ariels, but only adequate. More headroom would be nice, but not at the expense of the quality I already have. That has been the primary goal all along.
Well, it turns out that a true 92 dB/meter/watt is pretty close to the upper bound of direct-radiator tweeters. You can get slightly more, but only just a little bit. The Ariel II would have been only slightly more efficient, and I'm not even sure modern drivers are any better than what I was using twenty years ago.
So the search has been for a horn that doesn't sound like a horn, but retains horn dynamics and vividness of tone colors. I'm not talking about always-there, additive coloration, but the capability of playing tone colors when they're present in the source.
I should mention that Gary Dahl has very critical ears; he finds the sound of most high-end equipment unsuited for classical music. I can only agree. Most of it mangles beyond recognition the sound of live symphony orchestra, to the point where most recordings are unlistenable and not enjoyable at all. Unlike the claim relentlessly pushed in the magazines and audiophile websites, mainstream high-end equipment isn't "accurate" in any sense, it is grotesquely inaccurate, and has the same relation to reality that a horror movie does to the real world. Based on what I hear in the hifi shops, RMAF, and the CES, less than 5% of the equipment on the market is suitable for music of acoustic origin. I enjoy the social aspects of the shows (very much), but the sound in most of the rooms is horrific, far worse than a table radio or car stereo. I have no idea why the taste in the high-end is so debased.
It also means I can't honestly answer queries about "what does this or that sound like" because my tastes don't accord with most of the industry. Gary Dahl, Gary Pimm, John Atwood and I share similar tastes, but I have no idea what most audiophiles enjoy. I've sat alongside audiophiles with checklists of subjective qualities, carefully ticking each box as they listen to a room at the RMAF, but to me it's either good or bad, with not much in between.
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The nature of the HOM at least as seen in horns is not expressed the same in direct drivers.The extended FR of the Be direct dome drivers with their classical flexural modal noise often starting at 10KHz or rather higher with materials of stiffer moduli and/or good HF damping gve a similar unpleasant masking hash to the sound. But this can often be rolled off if not notched out unlike HOM.
Not surprising the simplicity of the direct radiator gives designers a head start. I is great that Peter Walker put the ELS57 on the map in the early 50s, so at least we have a light our path to a new level of realism, what ever its modus operandi. HEIL, RAAL, PLASMA. The same applies to the good old triode, as it has kept trumping the solid state stuff as it comes through.
Regarding the realistic classical performances the BBC kindly broadcast local concerts which are so simply processed and broadcast they give credence to 'being there' with a good triode sytem. This is especially with a decent FM tuner or internet radio. For me its is a lottery whether a CD or SACD, is going to give me at best very clear clean dynamic but somehow reconstructed sound like, ham which has been turned into spam.
The joy of listening to the Remembrance Day brass band music played live is a truly great experience.
It is clear that a horn can produce something very special out of what is probably quite good without, And it is worth the effort but it is only in the fianal stages that it gets to the required standard. Peter Walker, Heil and others I guess spent 1000's of hours on their great ideas. With the new materials and computer modelling/testing as we all have discussed is giving the horn a renaissance. Even with the modest shallow wave guides these give a bit of a taster.
The fact that the ELS, well deployed horn and DHT are so revered shows, there is the big consensus still knows how great reproduced real music or theatre or ballet can sound. Maybe the show organisers can be reeducated, but not any time soon I guess, but they make a good meet.
Actually, if you are referring to the "Bob Smith" phase plug - which the vast majority are - it is designed to suppress the first acoustic mode across the diaphragm in the gap in front of it. It does not suppress the first mechanical mode of the diaphragm, which are usually circumferential around the rim.
Admittedly not the easiest approach, but it can be done and IMO the simplicity of not having to have a super tweeter and another crossover are worth the trouble. The 15" rim resonance is just above the 950 Hz crossover and does cause serious complications with the crossover values, but again, it can be done. With DSP its a lot easier. All my speakers going forward will probably be DSP. Its gotten so cheap that it is lower in cost than passive. Another hard rule of mine goes down the drain!!
No, sorry. I intend to keep those pricey diaphragms protected.
I opened up one of the ceramic/aluminum 745's and found that the diaphragm assembly remained attached to the rear cover. I wasn't able to separate the two. Not wanting to risk damage (these are Lynn's drivers), I just put it all back together. I need to know the proper procedure before trying anything more invasive.
There is a difference between covering a frequency range with flat frequency response and sounding beautiful while doing so. What I heard from the Be Radian exceeded any previous results I have obtained with compression drivers and horns, so I am pleased. Nothing else has had that "liquid" quality that makes everything more realistic, and never before have I heard compression drivers without some amount of sibilance.
A full decade is a lot to expect of a single driver. Even if the driver is up to the task, its dispersion will narrow with increasing frequency.
In the system I am building, the woofer and horn each cover about 3.5 octaves, the subwoofer and ribbon adding about 1.5 octaves on each end. I consider this to be a good balance. Importantly, the system sounds quite pleasing with just the woofer and horn. In this configuration it works well with recordings of sub-optimal quality, which is all too often the case with recordings that are otherwise excellent.
I certainly don't want to lead anyone into buying beryllium drivers based on my words; there is much work to be done yet. But I am not at all disappointed with the performance of the beryllium, and look forward to the possibilities.
I quit using beryllium compression drivers a few years ago because they wore on me and after a few years in and out of the system i decided enough was enough. Some times they sound marvelous, but not natural.
The way Radian normally attaches the diaphragm by clamping it down with the back chamber. That may be the reason your response is so rolled off on the top and bottom. Try loosing and tightening the screws while measuring the response. The older Renkus designs perfected this but Radian did not eliminate this problem. I see no reason wht the beryllium should measure so badly compared to aluminum
A full decade is not difficult for a mid compression driver if you use the right horn. Maybe yours beams?
The way Radian normally attaches the diaphragm by clamping it down with the back chamber. That may be the reason your response is so rolled off on the top and bottom. Try loosing and tightening the screws while measuring the response. The older Renkus designs perfected this but Radian did not eliminate this problem. I see no reason wht the beryllium should measure so badly compared to aluminum
A full decade is not difficult for a mid compression driver if you use the right horn. Maybe yours beams?
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