Calibration of amp packs with new tweeters

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Calibration of amp packs with new tweeters

Postby oeglen » Thu Dec 01, 2016 1:37 pm

Dear all.
I just got two new ATC SH25/76S tweeters to my SCM100 SLT. Earlier this year I bougt two new amp packs for SCM 100 and I am happy. The old crossovers is replaced with amps. My question is: as the amp packs are pretty new. December 2015, Are they optimizing with the new tweeters or are they optimized with my old SEAS tweeters.
Best regards Peter

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Re: Calibration of amp packs with new tweeters

Postby MattSPL » Thu Dec 01, 2016 2:25 pm

I would think that if your amps were replaced based on serial numbers, before you upgraded the tweeters, then the amps will be set for the old tweeters.
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Re: Calibration of amp packs with new tweeters

Postby studioman » Thu Dec 01, 2016 9:49 pm

J
E
A
L
O
U
S
:D
They say if you can remember the 60's, you weren't really there. Now somehow I have reached 62...oh shit, it's 63 now....How and when did THAT happen?....there's a lesson there somewhere if only I could figure it out...

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Re: Calibration of amp packs with new tweeters

Postby studioman » Thu Dec 01, 2016 10:02 pm

Yes, SO jealous....
However, for what it's worth, and I might be wrong about this, when I took my amp packs to ATC to have them recapped and realigned, I chatted to one of the technicians and I think it was mainly the bass response that needed adjusting due to the fact that I was rehousing my ATC amps and drive units from old ATC PA65 cabinets into larger SCM150ASLT size cabinets. I suspect that the phasing of the various drive units at the crossover points actually remains the same because the crossover points are not changed. Of course, the levels only need to be adjusted relative to each other, so it would make sense to me that the midrange is left unadjusted, and the other two drivers i.e. bass and hf, are then adjusted relative to the mid. As I say, I might be off the mark here, but I think that's what happens.
There are presets on the circuit board which are only accessible from inside, which adjust the level and phase of various units. It is these which, if anything, the technicians need to adjust.
My realignment only took five minutes or so, if you can get the amp packs back to ATC.
And I'm still jealous.
They say if you can remember the 60's, you weren't really there. Now somehow I have reached 62...oh shit, it's 63 now....How and when did THAT happen?....there's a lesson there somewhere if only I could figure it out...

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Re: Calibration of amp packs with new tweeters

Postby Brad Lunde » Fri Dec 02, 2016 5:31 am

Studioman has it right.

This is the exact issue with replacing your old tweeters with ATC's new tweeters. Imagine you have a a well calibrated speaker that sounds flat and is set up right but has an old tweeter part that is 1dB down compared to a new ATC tweeter. Put in the new ATC tweeter without adjustment and the new tweeter is now 1dB too loud, +1dB from where it should be. You will have a speaker that sounds bright- you might even blame the new tweeters if you didn't know. Also imagine the reverse, an old tweeter is 1 dB hotter than the new ATC tweeter going in. Now the new ATC tweeter sounds dull and the speaker is dark. You would say, "wow these new tweeters suck". Too you the new tweeters are darker than the "old " ones. But that would NOT be true, its simply the drive level feeding the new tweeters is set 1dB too low because the old tweeter was 1dB too hot. To make it an ATC, its ALL about the calibration. This is the art, where the skill lies.

These old tweeters were a bit all over the place so dropping in new consistent sensitivity ATC tweets is not a plug and play operation. That is why there is a delay as we work out how to calibrate each speaker that is upgraded and make sure its the same as the factory would do if you sent in your speakers to them. Without calibration, the tweeter upgrade is not complete. With calibration, its like a new speaker!

Brad
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Re: Calibration of amp packs with new tweeters

Postby studioman » Sat Dec 03, 2016 9:35 am

Hi Brad, I totally agree with what you have explained. My feelings exactly. That's why I was a little puzzled about what i inderstood the ATC guy to say.
But I DO think you're right....
They say if you can remember the 60's, you weren't really there. Now somehow I have reached 62...oh shit, it's 63 now....How and when did THAT happen?....there's a lesson there somewhere if only I could figure it out...

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Re: Calibration of amp packs with new tweeters

Postby Lemen » Sun Dec 04, 2016 12:28 am

This thread has me thinking, please bear with me.
Other manufacturer's tolerances of drive-units are quite slack (as compared to ATC), hence why they recommend to replace drive-units as a matching pair. ATC drive-units are known to be very highly toleranced, whereby it's possible to replace a single driver should one have failed etc.

With the above in mind, maybe it would be possible to send just the amp-packs back to ATC to be calibrated for the new tweeters. Of course I'm sure the calibration is model dependant, but if the calibration values are known for each model, could the amp-packs be set-up accurately by using measuring equipment alone, ie, not requiring the actual speaker or drive units?
It would be SO much easier to send just the amp-packs to ATC rather than the complete pair of speakers, because I tell you, I'm not sure my ageing back could take it! I hope to have my own speakers upgraded not long into 2017.
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Re: Calibration of amp packs with new tweeters

Postby Brad Lunde » Tue Dec 06, 2016 5:36 am

Lemen wrote:This thread has me thinking, please bear with me.
Other manufacturer's tolerances of drive-units are quite slack (as compared to ATC), hence why they recommend to replace drive-units as a matching pair. ATC drive-units are known to be very highly toleranced, whereby it's possible to replace a single driver should one have failed etc.

With the above in mind, maybe it would be possible to send just the amp-packs back to ATC to be calibrated for the new tweeters. Of course I'm sure the calibration is model dependant, but if the calibration values are known for each model, could the amp-packs be set-up accurately by using measuring equipment alone, ie, not requiring the actual speaker or drive units?
It would be SO much easier to send just the amp-packs to ATC rather than the complete pair of speakers, because I tell you, I'm not sure my ageing back could take it! I hope to have my own speakers upgraded not long into 2017.


I think documentation for ALL history of all drivers past and present would be needed under this scenario?

Brad
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Re: Calibration of amp packs with new tweeters

Postby linger63 » Tue Dec 06, 2016 6:03 pm

error
Last edited by linger63 on Tue Dec 06, 2016 6:13 pm, edited 1 time in total.

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Re: Calibration of amp packs with new tweeters

Postby linger63 » Tue Dec 06, 2016 6:11 pm

linger63 wrote:
Lemen wrote:It would be SO much easier to send just the amp-packs to ATC rather than the complete pair of speakers, because I tell you, I'm not sure my ageing back could take it! I hope to have my own speakers upgraded not long into 2017.


You have NO IDEA how lucky you and your "ageing back" actually are. :lol:

I am in Australia which is where Billy Woodman actually hails from.........but I might as well be in Timbuktu for all the good it does me!!!!

Can't even begin to describe how ABSOLUTELY WOEFUL it is down here regarding all things ATC. :shock: :oops: :cry: :x

Brad........I have an ATC man crush..........can I move in with you at Lone Mountain Audio in Vegas?........ :mrgreen: ;)

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Re: Calibration of amp packs with new tweeters

Postby oeglen » Wed Dec 07, 2016 4:23 pm

Thanks to all for helping me. It still remain me with the question that my amp pack could actually be calibrated with the new tweeters. When I bougt the amp pack they didnt ask for serial no on the speaker, so ATC didnt know that my speakers till were with the SEAS. The took a pair of amp packs from their production in december 2015 and send them to me. So the amp packs maybe are calibrated to the new tweeters as all SCM100 were with new atc tweeters...or what do you think..?

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Re: Calibration of amp packs with new tweeters

Postby Lemen » Wed Dec 07, 2016 7:14 pm

oeglen wrote:So the amp packs maybe are calibrated to the new tweeters as all SCM100 were with new atc tweeters...or what do you think..?

I think "maybe" is the operative word. As you say, it's very possible, (perhaps even probable) that your new amp-packs, having come from 2015 stock, would be calibrated for the SH25-76S tweeter. The only way to be 100% sure is to contact ATC direct.
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Re: Calibration of amp packs with new tweeters

Postby Lemen » Wed Dec 07, 2016 7:20 pm

linger63 wrote:You have NO IDEA how lucky you and your "ageing back" actually are. :lol:

I am in Australia which is where Billy Woodman actually hails from.........but I might as well be in Timbuktu for all the good it does me!!!!

Can't even begin to describe how ABSOLUTELY WOEFUL it is down here regarding all things ATC. :shock: :oops: :cry: :x

Hmmm, I see your point about how lucky I am to have an ageing back :-)

Let's hope that ATC will soon sort something out for you down there in Oz.
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Re: Calibration of amp packs with new tweeters

Postby Brad Lunde » Thu Dec 08, 2016 2:45 pm

oeglen wrote:Thanks to all for helping me. It still remain me with the question that my amp pack could actually be calibrated with the new tweeters. When I bougt the amp pack they didnt ask for serial no on the speaker, so ATC didnt know that my speakers till were with the SEAS. The took a pair of amp packs from their production in december 2015 and send them to me. So the amp packs maybe are calibrated to the new tweeters as all SCM100 were with new atc tweeters...or what do you think..?


I think that you have a unique situation, and you should call the factory and ask for Rich Newman and see what he suggests. Maybe someone sold you amp packs and a mistake was made in not asking about this? Every now and then something goes off track in a complex factory operation (when people are involved!).

The idea that all the remaining SEAS tweeter supply is similar in sensitivity seems logical to me, so then the amp pack could be set up to fit that "current" production. But it is odd they did not ask you your serial numbers.

Brad
Brad Lunde
Lone Mountain Audio, part of TransAudio Group
ATC Importers USA

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Re: Calibration of amp packs with new tweeters

Postby Brad Lunde » Thu Dec 08, 2016 2:47 pm

linger63 wrote:
linger63 wrote:
Lemen wrote:It would be SO much easier to send just the amp-packs to ATC rather than the complete pair of speakers, because I tell you, I'm not sure my ageing back could take it! I hope to have my own speakers upgraded not long into 2017.


You have NO IDEA how lucky you and your "ageing back" actually are. :lol:

I am in Australia which is where Billy Woodman actually hails from.........but I might as well be in Timbuktu for all the good it does me!!!!

Can't even begin to describe how ABSOLUTELY WOEFUL it is down here regarding all things ATC. :shock: :oops: :cry: :x

Brad........I have an ATC man crush..........can I move in with you at Lone Mountain Audio in Vegas?........ :mrgreen: ;)



Hey Lemen

Sure, some on over! We'll put you to work!

Brad
Brad Lunde
Lone Mountain Audio, part of TransAudio Group
ATC Importers USA

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