Beta8CX ASD1001
Sorry about delay in posting results.
The first important thing that I have found about using these drivers is that the ASD1001, at least in the Beta8CX, has a rising bottom end.
Net result is that a 2nd order HP at 2.5 KHZ nets a 6th order response with -6dB at 1.5 KHz or so.
The second important thing is that the Beta8CX has a hump in response at 5-600Hz. This gives a forward character, obscuring everything else. Deal with this hump, or wonder forever what is wrong with the bass and the tweeter.
An OK, but not optimal passive crossover can be built with the tweeter padded -6dB, 2nd order Q.5 at 2.5 KHz, 1.4 KHz Q.7 LP on the woofer.
Use a parallel resonant notch on the woofer to deal with the hump. 3ohm//104uF//1mH for about a -2.5dB attenuating Q=1 Fo=500Hz response.
Zobel the woofer for best results.
My measurement axis is 30 degrees.
On axis The mid treble gets some roughness and the top octave peaks at 20K.
They sound very good to me.
Lively, no practical limit on dynamics. No harshness (see important things one and two above).
Sorry about delay in posting results.
The first important thing that I have found about using these drivers is that the ASD1001, at least in the Beta8CX, has a rising bottom end.
Net result is that a 2nd order HP at 2.5 KHZ nets a 6th order response with -6dB at 1.5 KHz or so.
The second important thing is that the Beta8CX has a hump in response at 5-600Hz. This gives a forward character, obscuring everything else. Deal with this hump, or wonder forever what is wrong with the bass and the tweeter.
An OK, but not optimal passive crossover can be built with the tweeter padded -6dB, 2nd order Q.5 at 2.5 KHz, 1.4 KHz Q.7 LP on the woofer.
Use a parallel resonant notch on the woofer to deal with the hump. 3ohm//104uF//1mH for about a -2.5dB attenuating Q=1 Fo=500Hz response.
Zobel the woofer for best results.
My measurement axis is 30 degrees.
On axis The mid treble gets some roughness and the top octave peaks at 20K.
They sound very good to me.
Lively, no practical limit on dynamics. No harshness (see important things one and two above).
Attachments
rkondra - thanks for the 8cx trap values re:"2nd order Q.5 at 2.5 KHz, 1.4 KHz Q.7 LP on the woofer" - what approximate values are those? are you using L-pad on the cd driver?
- winslow - did you try the stock Eminence values of 2mH/10uF and 3.3uF/0.33mH for Beta10cx? - I've got a couple of dips with a Peavey RX14 (not the driver - just the 14/10cx combo) so will graph it vs ASD1001, PRV280, APT50 and a B52 mylar
this highpass graph is the later Beta10cx in a Karlson-12 type - (the earlier Beta10cx had lower qts and a multipleat surround)
RX14 looks nice on its APT80 sized horn and just a 3.3uF cap sitting on my fake Druid with no baffle
Hawthorne ran ASD1001 pretty low on their original Silver Iris - about an octave lower than Eminence's project
- winslow - did you try the stock Eminence values of 2mH/10uF and 3.3uF/0.33mH for Beta10cx? - I've got a couple of dips with a Peavey RX14 (not the driver - just the 14/10cx combo) so will graph it vs ASD1001, PRV280, APT50 and a B52 mylar
this highpass graph is the later Beta10cx in a Karlson-12 type - (the earlier Beta10cx had lower qts and a multipleat surround)
RX14 looks nice on its APT80 sized horn and just a 3.3uF cap sitting on my fake Druid with no baffle
Hawthorne ran ASD1001 pretty low on their original Silver Iris - about an octave lower than Eminence's project
An externally hosted image should be here but it was not working when we last tested it.
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Thanks, do you have any graphs with more axes? I wanted to see if the Eminence compression driver looked any better than the Celestion I measured (see post 6 here). No filter makes that stop being harsh to my ears, which I established by process of elimination to be 100% due to issues 3-~8kHz. (note the lack of directivity in that range in my graph, although I'm not sure if it's that or resonant behavior in that range, or both).
I think your woofer response issue sounds like a combination of your cabinet and its intrinsic response, but I never got to the woofer beyond eliminating it as the source of harsh sound, so I'm not sure. I figured if the ASD1001 looked significantly different in that range, I'd pick one up, just in case.
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I'm still shopping and trying to decide what to do. But I would like to see the graphs you come up with and wonder about the Silver Iris XO too.
I was told the CT Celestion combo didn't change XOs except to lower the level of the compression driver due to it's increase in efficiency.
Has anyone measured and recorded the driver offset with the 10CX and different compression drivers?
I was told the CT Celestion combo didn't change XOs except to lower the level of the compression driver due to it's increase in efficiency.
Has anyone measured and recorded the driver offset with the 10CX and different compression drivers?
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Agreed. And it was worse before I beveled (1.5" bevel) the sides of the baffle. My baffle (ignoring bevel) is 12 X 15.5, with the driver C/L 7" from the top, centered side to side. The mids without the shallow notch filter sound clean, but forward.
The 4-8K dispersion issue does not bother me personally. It, and a number of other issues are for sure there. Especially when I delay the woofer and get the drivers in time alignment, I find them subjectively exceptional.
Attachments
Winslow's Beta 8 passive xo comment
That does work pretty well, and is about what I am settled on for a passive.
I do trap the midrange bump (might be just me or my baffle)
And the ASD1001 has a really healthy impedance rise Fo 1350 Hz.
Without a conjugate to damp that resonance passive xo's that I have tried sound really bad.
This does not show up at all as a problem with active xo's and a 100uF blocking cap.
I have not yet found a passive xo that I like without using a conjugate.
That does work pretty well, and is about what I am settled on for a passive.
I do trap the midrange bump (might be just me or my baffle)
And the ASD1001 has a really healthy impedance rise Fo 1350 Hz.
Without a conjugate to damp that resonance passive xo's that I have tried sound really bad.
This does not show up at all as a problem with active xo's and a 100uF blocking cap.
I have not yet found a passive xo that I like without using a conjugate.
Attachments
wonder why these aren`t mentioned
Coaxial Speaker Kits DIY Sound Group
the inexpensive denovo driver should be more capable than asd1001, which is one of the worst iv heared even with a 2k5 12db crossover.
Coaxial Speaker Kits DIY Sound Group
the inexpensive denovo driver should be more capable than asd1001, which is one of the worst iv heared even with a 2k5 12db crossover.
I dont know about the denovo, but the ASD1001 is pretty bad with parallel passive xover unless you deal with the very healthy resonance at Fo (1350 Hz) with a conjugate.
Add the conjugate and its much better, but not as good as when used with active xo.
I'm about to start a Beta 10cx/ PSD:2013S-16 build and am currently gathering the parts. Unfortunately I will not have new test equipment until Nov 7. Until then I am stuck in XO theory land.
Does anyone know if it is possible to add a delay to a passive XO? I am going to keep the XO external so I have options.
Some pics for fun.
Does anyone know if it is possible to add a delay to a passive XO? I am going to keep the XO external so I have options.
Some pics for fun.
Attachments
I did an article of all three: CX8, CX10 and CX12. PSD2002-driver was not any better (considering sound quality and integration) than cheap APT:50. I made two equally balanced versions, one with APT and another with PSD. No real difference and at least not to PSD's advantage...
The big point was to adjust tweeters balance - a little attennuation in 2-8kHz area and a bit more sparkle to top octave. All the coaxials, CX8, CX10 and CX12 are far from perfect wave guides to the tweeter and with flat balance the top is very unpleasent because of diffractions. However, if you attennuate the problem area just a bit the annoyance disappears.
Basic attennuation (L-Pad or simple series resistor) just sucks also the top octave and that makes the sound dull and lifeless. So one needs to give some extra energy there.
And one big point, CX12 is a lot better than either CX10 or CX8. It images better, it is more balanced and has both high sensitivity (95dB) and good bass. Floor version is easy: 100x37cm front panel, 30cm depth, driver's midpoint 24,5cm from top. Two reflex tubes, 10cm diameter and 20cm long. Both open it works in bigger rooms (or even outside), one open in smaller rooms and both plugged as a big on-wall speaker in small rooms.
Here's the article: Kaiutinrakennusohje Yksisilmäiset veljekset - hifi-PA-kaiuttimet Eminence Beta-8CX, Beta-10CX ja Beta-12CX -koaksiaalielementeistä | AudioVideo.fi
In Finnish of course, but the pics are in universal
.
The big point was to adjust tweeters balance - a little attennuation in 2-8kHz area and a bit more sparkle to top octave. All the coaxials, CX8, CX10 and CX12 are far from perfect wave guides to the tweeter and with flat balance the top is very unpleasent because of diffractions. However, if you attennuate the problem area just a bit the annoyance disappears.
Basic attennuation (L-Pad or simple series resistor) just sucks also the top octave and that makes the sound dull and lifeless. So one needs to give some extra energy there.
And one big point, CX12 is a lot better than either CX10 or CX8. It images better, it is more balanced and has both high sensitivity (95dB) and good bass. Floor version is easy: 100x37cm front panel, 30cm depth, driver's midpoint 24,5cm from top. Two reflex tubes, 10cm diameter and 20cm long. Both open it works in bigger rooms (or even outside), one open in smaller rooms and both plugged as a big on-wall speaker in small rooms.
Here's the article: Kaiutinrakennusohje Yksisilmäiset veljekset - hifi-PA-kaiuttimet Eminence Beta-8CX, Beta-10CX ja Beta-12CX -koaksiaalielementeistä | AudioVideo.fi
In Finnish of course, but the pics are in universal
.
I did an article of all three: CX8, CX10 and CX12. PSD2002-driver was not any better (considering sound quality and integration) than cheap APT:50. I made two equally balanced versions, one with APT and another with PSD. No real difference and at least not to PSD's advantage...
The big point was to adjust tweeters balance - a little attennuation in 2-8kHz area and a bit more sparkle to top octave. All the coaxials, CX8, CX10 and CX12 are far from perfect wave guides to the tweeter and with flat balance the top is very unpleasent because of diffractions. However, if you attennuate the problem area just a bit the annoyance disappears.
Basic attennuation (L-Pad or simple series resistor) just sucks also the top octave and that makes the sound dull and lifeless. So one needs to give some extra energy there.
And one big point, CX12 is a lot better than either CX10 or CX8. It images better, it is more balanced and has both high sensitivity (95dB) and good bass. Floor version is easy: 100x37cm front panel, 30cm depth, driver's midpoint 24,5cm from top. Two reflex tubes, 10cm diameter and 20cm long. Both open it works in bigger rooms (or even outside), one open in smaller rooms and both plugged as a big on-wall speaker in small rooms.
Here's the article: Kaiutinrakennusohje Yksisilmäiset veljekset - hifi-PA-kaiuttimet Eminence Beta-8CX, Beta-10CX ja Beta-12CX -koaksiaalielementeistä | AudioVideo.fi
In Finnish of course, but the pics are in universal
Thanks for that information I have read most of the article (google translate sucks at Finnish) but I got the general message. I am integrating this with a dedicated sub-woofer and was looking for more punch from the mid-woofer. Eminence is right down the road and this build will be shown to the Eminence staff for evaluation. I want to integrate an acoustic lens system into the design. A second design will be for use behind an "acustically transparent" Home Theatre screen. (which do some lens functions by themselves).
Reference:
https://www.jblpro.com/pub/obsolete/Acoustic_Lens_Family1.pdf
http://www.diyaudio.rs/JBL/JBL%20-%20The%20Acoustical%20Lens%20%281962%29.pdf
If you don't mind would you translate a small part of the article linked above?
Vaan onko näillä asioilla oleellista vaikutusta? Ei, ei ole. Pölykupin poiston tuoma diskanttitason desibelin-parin nousu tarkoittaa, että sitä ylädiskanttia pitää sitten vaimentaa jakosuotimessa enemmän. Tarkoittaa pykälää tai paria suurempaa vastusta. En näe pointtia. Mutta se pölykuppihan oli vain ovi, jonka kautta päästään leikkelemään basson puhekelan runko kartion tasolle? Josta ei seuraa mittauksissa minkäänlaista hyötyä verrattuna vakioelementtiin. Beta-10CX:n diskanttitoisto oli aivan yhtä rosoinen suoraan edestä mitattuna vakioelementillä, ilman pölykuppia olevalla muuten vakioelementillä ja puhekelan rungoltaan lyhennetyllä elementillä.
Vain jos leikkausjätettä sattuu saamaan sinne ilmarakoon, se sekä näkyy mittalaitteistolla että kuuluu äänen lopullisena vaimentumisena.
- See more at: Kaiutinrakennusohje Yksisilmäiset veljekset - hifi-PA-kaiuttimet Eminence Beta-8CX, Beta-10CX ja Beta-12CX -koaksiaalielementeistä | AudioVideo.fi
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