ralphs99 said:
does he have an email addy? I'd love to talk to him about his painting technique, I am DYING to improve 🙂
-dave
Ralph:
I've worked with a few Volt drivers in the past, including the B250.8. You really aren't hearing them at their best within a sealed enclosure, much better is ported and you'll notice extra dynamics a more 'free' sounding lower/upper midbass and just a generally better bass response all round.
I used a 55ltr enclosure tuned to 35hz for each driver.
I've worked with a few Volt drivers in the past, including the B250.8. You really aren't hearing them at their best within a sealed enclosure, much better is ported and you'll notice extra dynamics a more 'free' sounding lower/upper midbass and just a generally better bass response all round.
I used a 55ltr enclosure tuned to 35hz for each driver.
Hi Newfinish,
I guess the answer to your question is yes, yes and no.
What I mean is that the ATC mid is capable of startling realism, but I think there is also some small colouration. In fact all drivers and systems have some colouration. It's just a question of what compromises you want to make. I am already very happy with the ATC's performance and I expect it to get even better as my development continues. It's not perfect but seems to offer a combination of characteristics that are unique as far as I am aware.
Cheers, Ralph
I guess the answer to your question is yes, yes and no.
What I mean is that the ATC mid is capable of startling realism, but I think there is also some small colouration. In fact all drivers and systems have some colouration. It's just a question of what compromises you want to make. I am already very happy with the ATC's performance and I expect it to get even better as my development continues. It's not perfect but seems to offer a combination of characteristics that are unique as far as I am aware.
Cheers, Ralph
Hi Shin,
Thanks for the link to the concept 7 review. I found it very interesting. Particularly the avererage amplitude response showing the nulls at the upper crossover frequency. I can see the same effect in my setup and was wondering if ATC do anything about it.
I might try vented enclosures for the Volts but I really want to have a go at a dipole setup for the Volts to see how that compares to sealed enclosures. I've been giving some thought to bass performance and so far I don't miss anything. The bass performance of the sealed Volts has been beyond my expectations. On paper they look like good rather than great drivers, but listening tests have been very impressive.
Cheers,
Ralph.
Thanks for the link to the concept 7 review. I found it very interesting. Particularly the avererage amplitude response showing the nulls at the upper crossover frequency. I can see the same effect in my setup and was wondering if ATC do anything about it.
I might try vented enclosures for the Volts but I really want to have a go at a dipole setup for the Volts to see how that compares to sealed enclosures. I've been giving some thought to bass performance and so far I don't miss anything. The bass performance of the sealed Volts has been beyond my expectations. On paper they look like good rather than great drivers, but listening tests have been very impressive.
Cheers,
Ralph.
Hi Lemans,
I bought the boxes some time ago and don't know how I could contact him now, sorry.
I haven't looked, but I imagine there would be plently to forum members who can help you.
Have you seen Shinobiwan's boxes? They look very slick, maybe he can give you some tips?It's a great thread as well.
http://www.diyaudio.com/forums/showthread.phps=&threadid=62391
Cheers,
Ralph.
I bought the boxes some time ago and don't know how I could contact him now, sorry.
I haven't looked, but I imagine there would be plently to forum members who can help you.
Have you seen Shinobiwan's boxes? They look very slick, maybe he can give you some tips?It's a great thread as well.
http://www.diyaudio.com/forums/showthread.phps=&threadid=62391
Cheers,
Ralph.
ralphs99 said:
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The requested URL /forums/showthread.phps=&threadid=62391 was not found on this server.
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🙂
Hmmm,
maybe you can't link to a thread. Try a link to a post instead:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=52876&perpage=10&pagenumber=23
Cheers,
Ralph
maybe you can't link to a thread. Try a link to a post instead:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=52876&perpage=10&pagenumber=23
Cheers,
Ralph
ralphs99 said:
The ones in the shot you linked to weren't finished and hence the finish looks rough in the shots.
This link is after I sanded flat and then rubbed out for a high gloss finish.
http://www.diyaudio.com/forums/showthread.php?postid=690748#post690748
BTW Those ones went on the bonfire last night 😀 Bit gutted to see them go after all the hardwork but I just had to have a clearout of all the unfinished cabinets in the house and the shed since it was getting beyond a joke.
A few notes on the ATC SM75-150S measurements:
Part of the weakness at the low frequency end of the spectrum is due to baffle step. The test baffle was 300mm wide, so the effect should be starting to kick in below about 400Hz.
There's a small discontinuity in the amplitude and phase response at 1.8kHz although this isn't visible in the impedance plot. I believe this to be an artifact of the driver as it is present in all my later system level directivity measurements.
The first breakup mode is occuring at 4.3kHz, but this is outside the passband when using steep crossover slopes. I'm using 24dB/oct at 3.5kHz the moment, so the breakup mode is down by about 10dB and isn't a big contributor to the SPL at this frequency.
The ATC is becoming directional above 2.5kHz and has -6dB points of 45 degrees at around 3.5kHz. So around 3.5kHz is a logical crossover frequency, ideally handing over to a tweeter with some low frequency directivity control. Crossing to the ER4 gives a discontinuity between 2.5 and 4.5kHz in the horizontal axis and power response.
Cheers,
Ralph
Part of the weakness at the low frequency end of the spectrum is due to baffle step. The test baffle was 300mm wide, so the effect should be starting to kick in below about 400Hz.
There's a small discontinuity in the amplitude and phase response at 1.8kHz although this isn't visible in the impedance plot. I believe this to be an artifact of the driver as it is present in all my later system level directivity measurements.
The first breakup mode is occuring at 4.3kHz, but this is outside the passband when using steep crossover slopes. I'm using 24dB/oct at 3.5kHz the moment, so the breakup mode is down by about 10dB and isn't a big contributor to the SPL at this frequency.
The ATC is becoming directional above 2.5kHz and has -6dB points of 45 degrees at around 3.5kHz. So around 3.5kHz is a logical crossover frequency, ideally handing over to a tweeter with some low frequency directivity control. Crossing to the ER4 gives a discontinuity between 2.5 and 4.5kHz in the horizontal axis and power response.
Cheers,
Ralph
Hi!
THANK YOU! THANK YOU! You enter History.
It's good to have some FR even if it is closely related to your method and hardware (could you tell me what sound card, mic and preamp you use just for my reference).
I wish Shinobiwan had done the same. It would have been perfect for cross analysis.
I can recognise Just LMS it's a good soft for quick design however it is bit limited when it comes to in deph measurments like IMD, THD, time domain... I advocate you to find a demo of CoolEdit 2000 and download Aurora plugins from http://www.ramsete.com/Aurora/homepage.html
With a log seep sinus you can acces to very precise data, even in time domain for time aligment.
Thanks again
@+
Maiky
THANK YOU! THANK YOU! You enter History.
It's good to have some FR even if it is closely related to your method and hardware (could you tell me what sound card, mic and preamp you use just for my reference).
I wish Shinobiwan had done the same. It would have been perfect for cross analysis.
I can recognise Just LMS it's a good soft for quick design however it is bit limited when it comes to in deph measurments like IMD, THD, time domain... I advocate you to find a demo of CoolEdit 2000 and download Aurora plugins from http://www.ramsete.com/Aurora/homepage.html
With a log seep sinus you can acces to very precise data, even in time domain for time aligment.
Thanks again
@+
Maiky
Holy cr*p did I just about choke when I looked up the prices of the SM75-150s. $720/ea + $140 for the faceplate. Ouch! 
With that said, if they are good, they are good. Couple of simple stupid questions though, are they completely enclosed? Would you have to place them in a box or could a baffle alone work? How wide of a dispersion do you estimate they have, say compared to a midwoofer?
I imagine if you are xo'ing at 375hz to dipole subs you might have some power response discontinuities here wouldn't you? I guess it would depend on the baffle width.
With that said, if they are good, they are good. Couple of simple stupid questions though, are they completely enclosed? Would you have to place them in a box or could a baffle alone work? How wide of a dispersion do you estimate they have, say compared to a midwoofer?
I imagine if you are xo'ing at 375hz to dipole subs you might have some power response discontinuities here wouldn't you? I guess it would depend on the baffle width.
JoshK said:
They are a closed back design and have no rear wave. They can be mounted on a baffle or placed in a box, you won't notice much at all difference between the two because of the above.
The dispersion is excellent and one of its selling points.
Hi Ralph,
My measurements tell a very similar story to yours.
I've also got the 4dB dip at 3.3Khz, the strange thing is that I've owned both the standard and super versions of the SM75-150 and both the standard models I tested had no dip at 3.3Khz, which leads me to believe its BL related since they both share exactly the same design otherwise.
EDIT: Take a look back at the review I linked to earlier and specifically the averaged frequency plot for the SCM70 Center. It has no dip in the 3.3Khz region - I believe they used the standard version in the center here or maybe they just used EQ. Eitherway its fine there.
My measurements tell a very similar story to yours.
I've also got the 4dB dip at 3.3Khz, the strange thing is that I've owned both the standard and super versions of the SM75-150 and both the standard models I tested had no dip at 3.3Khz, which leads me to believe its BL related since they both share exactly the same design otherwise.
EDIT: Take a look back at the review I linked to earlier and specifically the averaged frequency plot for the SCM70 Center. It has no dip in the 3.3Khz region - I believe they used the standard version in the center here or maybe they just used EQ. Eitherway its fine there.
Hi Maiky,
You're welcome!
My measurement setup is pretty simple. A Sennheiser KE-4 electret capusle on a 8mm x 30cm tube with a custom pre-amp feeding a Soundblaster Audigy NX USB soundcard. The measurement microphone sits on a camera tripod or mic stand.
You're right about LsPCAD's capabilities. To date it's been sufficient for what I've wanted to do and I couldn't really justify a more sophisticated software tool. But I'll check out the Aurora plugins, they look promising. Thanks for the link!
What kind of system are you thinking of for the SM75-150S? I'm very interested in your ideas.
Cheers,
Ralph.
You're welcome!
My measurement setup is pretty simple. A Sennheiser KE-4 electret capusle on a 8mm x 30cm tube with a custom pre-amp feeding a Soundblaster Audigy NX USB soundcard. The measurement microphone sits on a camera tripod or mic stand.
You're right about LsPCAD's capabilities. To date it's been sufficient for what I've wanted to do and I couldn't really justify a more sophisticated software tool. But I'll check out the Aurora plugins, they look promising. Thanks for the link!
What kind of system are you thinking of for the SM75-150S? I'm very interested in your ideas.
Cheers,
Ralph.
Hi Josh,
Yep the ATC's are expensive. But you get a lot of driver for the money. It's made to tight tolerances and appears very rugged. It's also a professional product so it will be supported with spares for eternity.
Dispersion is basically that of a 90mm piston. Constrained by the baffle at low frequencies and gradually becoming more directional at higher frequencies. Usable to about 3.5kHz with around 90 degree dispersion. The waveguide is too small to give any loading at the lowest freqencies but I feel probably gives the driver some of it's startling impact a bit further up.
So compared to a typical 4" cone, the dispersion should be very similar.
You might well be right about there being some power response issues between the ATC and dipole mid-bass. The directivity of the ATC is approximately 6dB on a 300mm+ baffle down to 400Hz or so. A dipole has directivity of about 4.8dB, so it may be quite a good match. I'll have to try it and see.
Cheers,
Ralph
Yep the ATC's are expensive. But you get a lot of driver for the money. It's made to tight tolerances and appears very rugged. It's also a professional product so it will be supported with spares for eternity.
Dispersion is basically that of a 90mm piston. Constrained by the baffle at low frequencies and gradually becoming more directional at higher frequencies. Usable to about 3.5kHz with around 90 degree dispersion. The waveguide is too small to give any loading at the lowest freqencies but I feel probably gives the driver some of it's startling impact a bit further up.
So compared to a typical 4" cone, the dispersion should be very similar.
You might well be right about there being some power response issues between the ATC and dipole mid-bass. The directivity of the ATC is approximately 6dB on a 300mm+ baffle down to 400Hz or so. A dipole has directivity of about 4.8dB, so it may be quite a good match. I'll have to try it and see.
Cheers,
Ralph
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