By my understanding one of the main problems with full ranges and by extension the coaxials is that the cone is also a waveguide for the highs. The Doppler effect from the cone movements distorts all high frequencies, so we must limit the excursion at all costs. If the driver is capable of sub-100 Hz frequencies it's no help, it's better be high passed. 100 Hz is 3 m, it's extremely omni, it may be handled by a sub located anywhere.
https://www.fulcrum-acoustic.com/audio-technology-insights-resources/building-a-better-coax/
https://www.fulcrum-acoustic.com/audio-technology-insights-resources/temporal-equalization-tq/
For patents i'll let you do some search as D.Gunness published a bunch either about temporal eq or passive cardio or other Fulcrum Audio technological innovation...
Presonus licenced both the drivers and dsp from them in Sceptre series.
https://www.fulcrum-acoustic.com/audio-technology-insights-resources/temporal-equalization-tq/
For patents i'll let you do some search as D.Gunness published a bunch either about temporal eq or passive cardio or other Fulcrum Audio technological innovation...
Presonus licenced both the drivers and dsp from them in Sceptre series.
You didn’t say, so I don’t know why you thought they’re MOR. Wrongly
You could be forgiven for missing that was AUD 439. Around USD 260
But you’re getting both a midwoofer and a tweeter, ie = USD 130/ driver
with better directivity than separates
And excellent quality
https://hificompass.com/en/reviews/satori-mt19cp-8-75-coaxial-speaker-review
Agree. Almost deserves a somewhat romantic or Euphoric statement.
With right combination of filter orders asymmetric or symmetrical
Coaxial Can be considered almost dream like Vertical for anybody familiar with common center to center challenges of separates.
The challenge is finding a smaller tweeter that performs well inside a coaxial system.
Been exploring options. Think a 4" driver and 3/4 tweet offers best tradeoffs.
Then separate large woofer for low frequency performance. Which pose little to no phase issue at lower crossover points.
True in principle. but you’re assuming the effect is very bad and very obvious
Like many things, the execution can reduce the inherent limitations. (Refer rear engine + a lot of power, and Porsche 911s).
I can’t recall people saying Kef’s or MoFi’s have poor treble
Here’s data - A Fly in the ointment - on a well-designed coax.
https://hificompass.com/en/reviews/satori-mt19cp-8-75-coaxial-speaker-review#13
While in the specific tests he did conclude “the parasitic frequency modulation caused by the Doppler effect is quite significant and is stronger the greater the amplitude of the midwoofer cone oscillations and the higher the frequency of the tweeter signal” …
Overall “The upper bass and midrange are excellent … … …… and
“The highs are not far behind the low and mid frequencies in terms of quality” so it can’t be too bad
you said we must limit the excursion “at all costs”. Absolutely, it’s desirable.
But he’s the most thorough driver reviewer around, and in his conclusions did not mention the Doppler effect. So its effect isn’t nearly as evident as his data suggests.
Me, I’d always want to use a dedicated woofer with a mid-woofer, whether it’s co-ax or not. (Except if it were a Purifi)
Doppler effect is hardly relevant most of the theory is imagined.
4" driver with 300 Hz or higher crossover hardly moves at listening levels.
For extremely large coaxial the waveguide for tweeter can be non moving.
With coaxial design is better to not think of imagined issues and design around real issues.
4" driver with 300 Hz or higher crossover hardly moves at listening levels.
For extremely large coaxial the waveguide for tweeter can be non moving.
With coaxial design is better to not think of imagined issues and design around real issues.
Erin (bikinpunk here) tested KEF coaxials, tweeter response with woofer cone steadily at +/-3mm tested with KEF Q100 driver
Scroll down...
https://web.archive.org/web/2018030...ker-driver-tests/other-speakeer-driver-tests/
Another (closed) thread about coaxials https://www.diyaudio.com/community/threads/coax-woofer-cone-movement-impact-on-hf-response.275806/ with comment by Anrew Jones. Doppler effect is not a problem, that is how sound pressure variations (waves) propagate in air, despite of how they are excited! And that is how they appear in waveform display in oscilloscope or eg. Audacity if you zoom enough
Scroll down...
https://web.archive.org/web/2018030...ker-driver-tests/other-speakeer-driver-tests/
Another (closed) thread about coaxials https://www.diyaudio.com/community/threads/coax-woofer-cone-movement-impact-on-hf-response.275806/ with comment by Anrew Jones. Doppler effect is not a problem, that is how sound pressure variations (waves) propagate in air, despite of how they are excited! And that is how they appear in waveform display in oscilloscope or eg. Audacity if you zoom enough
Sound is pulsating air pressure variations and usually we can visualize it as waveform display in oscilloscope or eg. Audacity if you zoom enough. Different frequencies always ride on each other and modulate, this applies to all sounds, also from "natural" sources. The question is if a loudspeaker system makes any changes to the original stimulus.
Doppler distortion is modulation of pitch (frequency) https://en.wikipedia.org/wiki/Doppler_effect
Intermodulation distortion is added harmonic distortion, we can see them in multi(sine) tone tests
Audibility question with loudspeakers
https://pubs.aip.org/asa/jasa/artic...y-of-Doppler-distortion-in?redirectedFrom=PDF
And I agree that we should use a woofer (or several) with coaxial mid-tweeter! Been there too, done that.
https://www.audiosciencereview.com/forum/index.php?threads/kef-r11-meta-tower-speaker-review.53282/
"R11 Meta roared to action, delivering optimal and super enjoyable response on every reference track I threw at it. Science and excellent engineering works!"
Doppler distortion is modulation of pitch (frequency) https://en.wikipedia.org/wiki/Doppler_effect
Intermodulation distortion is added harmonic distortion, we can see them in multi(sine) tone tests
Audibility question with loudspeakers
https://pubs.aip.org/asa/jasa/artic...y-of-Doppler-distortion-in?redirectedFrom=PDF
And I agree that we should use a woofer (or several) with coaxial mid-tweeter! Been there too, done that.
https://www.audiosciencereview.com/forum/index.php?threads/kef-r11-meta-tower-speaker-review.53282/
"R11 Meta roared to action, delivering optimal and super enjoyable response on every reference track I threw at it. Science and excellent engineering works!"
For the OP’s original question……For starters, it’s beyond a niche market…….drivers for DIYers alone are barely sustainable.
If I were developing a coax for market, since the drivers are already chosen to work together, I’d task a design for an optimal crossover and offer that as well making it less of a challenge for the end user.
Now the brutal truth?…..there’s perception and then there’s measurements. My own perception is that COAX drivers are lacking in clarity of upper midrange and low treble at volume compared to their counterparts. At normal volumes in the near to near mid field…..excellent……but they can’t compare beyond. Doppler distortion I suspect is the issue.
If I were developing a coax for market, since the drivers are already chosen to work together, I’d task a design for an optimal crossover and offer that as well making it less of a challenge for the end user.
Now the brutal truth?…..there’s perception and then there’s measurements. My own perception is that COAX drivers are lacking in clarity of upper midrange and low treble at volume compared to their counterparts. At normal volumes in the near to near mid field…..excellent……but they can’t compare beyond. Doppler distortion I suspect is the issue.
Has anyone brought up car audio "coaxial"? DSP time-delay tweeter to be coherent with cone. Or do my reflector thing.
There are also many brands from Taiwan and China that sell home-hifi coax drivers or speakers of all sizes at different price points.
There are also many brands from Taiwan and China that sell home-hifi coax drivers or speakers of all sizes at different price points.
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There was a company who made such a speaker
IIRC, they had a 12 inch code speaker and a frame to hold the tweeter in front. Can't remember the company name though
Brian
IIRC, they had a 12 inch code speaker and a frame to hold the tweeter in front. Can't remember the company name though
Brian
Excellent summary Juhazi, nails it. … and encourages me further
I guess you’ve used a few of the better coaxials, and know quite a few more … do you have some you'd recommend or particularly liked.
In particular for very clean sound. And sometimes at “highish” volume with “ample” headroom and low compression.
Quantitatively say target maximum output at max long-term power of say 110 dB/ 1 m or more. I’d think that would be a good indicator of ample headroom for the occasional favourite album listened with “clean” peaks of 105 dB at around 3- 3 1/2 m
I ask, as recently for the first time I developed a strong urge to do a coax.
Where very clean sound/ low distortion is very much the dominant criteria.
Other criteria … pretty open.
preferably dipole. but as it’d be with one or two woofers it wouldn’t need higher Xmax to help out at the low end.
Efficiency not important by itself - I’d use whatever good amp of adequate power to reach the SPL goal for whatever is the driver’s sensitivity
Frequency of xo to the woofer - from 100-300 Hz.
Size anywhere from 6 to 12 inches.
If the FR isn’t quite the smoothest, could be mostly dealt with by the DSP used for the xo.
As you’d know, at least half a dozen very good manufacturers have one or more drivers meeting most of the criteria.
Mostly pro drivers.
What comes to mind?
I guess you’ve used a few of the better coaxials, and know quite a few more … do you have some you'd recommend or particularly liked.
In particular for very clean sound. And sometimes at “highish” volume with “ample” headroom and low compression.
Quantitatively say target maximum output at max long-term power of say 110 dB/ 1 m or more. I’d think that would be a good indicator of ample headroom for the occasional favourite album listened with “clean” peaks of 105 dB at around 3- 3 1/2 m
I ask, as recently for the first time I developed a strong urge to do a coax.
Where very clean sound/ low distortion is very much the dominant criteria.
Other criteria … pretty open.
preferably dipole. but as it’d be with one or two woofers it wouldn’t need higher Xmax to help out at the low end.
Efficiency not important by itself - I’d use whatever good amp of adequate power to reach the SPL goal for whatever is the driver’s sensitivity
Frequency of xo to the woofer - from 100-300 Hz.
Size anywhere from 6 to 12 inches.
If the FR isn’t quite the smoothest, could be mostly dealt with by the DSP used for the xo.
As you’d know, at least half a dozen very good manufacturers have one or more drivers meeting most of the criteria.
Mostly pro drivers.
What comes to mind?
For loud/PA use check pro drivers 10-15" (some B&C used in this design by kimmosto, VituixCAD man). I can't recommend dipoles for high spl.
https://aaltospeakers.fi/en/product/taipuu-speakers-3-tie-dsp-aktiivikaiutinpari/
My latest diy project used a 12" coaxial and it was very difficult... the horn made problems.
Pics here https://photos.app.goo.gl/hGFkqajgoVwWrzL59
https://aaltospeakers.fi/en/product/taipuu-speakers-3-tie-dsp-aktiivikaiutinpari/
My latest diy project used a 12" coaxial and it was very difficult... the horn made problems.
Pics here https://photos.app.goo.gl/hGFkqajgoVwWrzL59
given the combination of distance and desired SPL, otbe (other things being equal), a 12 makes most sense
I’ve only read part of your thread, but from your experience likely to play safe and exclude horns
From memory, 12 inch pro coaxials from good brands … half a dozen or a few more. I should do a shortlist.
otbe, one with a low Fs/ Qms. Often said to be the best of the older 15 inches, I just remembered that the Altec 416’s Fs/ Qms of only 3.5 indicates very low loss > less inertia/ better control > better micro details (and performance at the lower end of the SPL scale).
Unless I find some comparative experience with “other things being equal” inc the parameters can’t be separated as likely have a better SQ.
I’ve only read part of your thread, but from your experience likely to play safe and exclude horns
From memory, 12 inch pro coaxials from good brands … half a dozen or a few more. I should do a shortlist.
otbe, one with a low Fs/ Qms. Often said to be the best of the older 15 inches, I just remembered that the Altec 416’s Fs/ Qms of only 3.5 indicates very low loss > less inertia/ better control > better micro details (and performance at the lower end of the SPL scale).
Unless I find some comparative experience with “other things being equal” inc the parameters can’t be separated as likely have a better SQ.
But is that with a coax like the one in LS50 or the one in R3? Because one is a midwoofer, the other a dedicated midrange. And I can't really fault the R3 midrange version.