I heard the SM75-150S isn't available anymore. So what is the difference between the S and the non-S version? Is it mainly sensitivity? I've seen Shin's measurements of the SM75-150S and the distortion levels are very impressive, and I wonder how the non-S version compares?
I have a pair of the sm75-150s 16 ohm for sale.
Cosmetically not perfect.
About 13-15 years old. Used mostly with a 300B amp. It put out a whopping 5 watts.
PM me if interested.
Cosmetically not perfect.
About 13-15 years old. Used mostly with a 300B amp. It put out a whopping 5 watts.
PM me if interested.
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Thanks, but if the only difference is the sensitivity, I think I might rather get a new pair of non-S versions, since 13+ years seems pretty old.
Really, has no-one ever found out the exact differences between these drivers?
Really, has no-one ever found out the exact differences between these drivers?
You could just go to ATCs site and download the zip file (pdf).
But apart from sensitivity, total magnetic flux and flux density they appear identical.
But apart from sensitivity, total magnetic flux and flux density they appear identical.
From what I have read, the only difference is the sensitivity increase for the S version. The cone assembly is the same for both (the same recone kits work for both versions). If you look at pictures of the units, the S version has a much bigger/stronger magnet which provides the sensitivity increase.
Cheers
Cheers
One has to wonder then, why ATC use the S version even in their active speakers where sensitivity is not an issue, and also in their passive ones with low sensitivity.
I did email ATC to ask the difference, but I guess they are on holiday at the moment since they haven't replied for a couple of days.
I did email ATC to ask the difference, but I guess they are on holiday at the moment since they haven't replied for a couple of days.
It has to keep up with up to two 15" woofers while maintaining sufficient headroom for un-compressed signals. 3dB can count for a lot at times.
I think you're confusing sensitivity with maximum SPL. Some of the speakers using the S version only have ~86dB sensitivity.
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Both s and non-s only come in 16Ohm impedance so in a passive set up you only get 88dB for 2.83V from a non-s.
And in the larger actives it needs to keep up with twin woofers in terms of maxSPL.
And in the larger actives it needs to keep up with twin woofers in terms of maxSPL.
Oh yeah you're right. The spec sheet says sensitivity, but then they quote output for 1watt rather than voltage.
For both the S and non-S 8 ohm and 16 ohm versions are available. ATC uses the 16 ohm in their Active and the 8 ohm in the passive versions of their speakers. Proac used the 16ohm non-S version in the EBS, Studio Tower and Proac Response Fours (all passive).
Nobody really answered the question. Some people here think the S version is fantastic and others say there is no difference hardly. There are other things that matter also. Maybe they were listening to different setups.
I don't think there is anything fancy really: the S version has a stronger magnet, that results in more efficiency in the highs (higher mass break frequency), that's pretty much all there is to it.
http://www.solen.ca/pdf/atc/sm150.pdf
http://www.solen.ca/pdf/atc/sm150s.pdf
http://www.solen.ca/pdf/atc/sm150.pdf
http://www.solen.ca/pdf/atc/sm150s.pdf
Attachments
That looks very similar. We could just cross the tweeter a little lower to get more detail in the lower highs. I don't know. :S
But where to find them for cheap?! On a students budget I will only afford one. Called ATC in the UK and they wanted ~300 pounds for it.
Oh, and ATC is keeping the S version to their own speakers now, I asked them on the phone. So this discussion is pretty fruitless.
I am planning to use my single, mono 🙁 SM75-150 driver to build a ATC SCM50 clone to go with my Krell KSA-100 clone, of which none is of course completed. I happen to have the chinese made tweeters from the ATC SCM16A (still on ebay for $21: "atc tweeter") and a pair of unknown ATC PA75-260 STD 8 ohm (!). Not the -314. Not the -243. Not the -234. But a rare -260. I measued also. 255mm across. It likes to be between 250Hz and 900Hz. They are very revealing. I played it a long time before they loosened up a bit, or my stereo warmed up properly. I was scared the first two days and thought, "what a crappy speaker I bought!" We will see if I can decide on a cabinet for these rarities. 255mm is not 243mm across, like in the original SCM50.
I asked ATC and they didn't have anyone old enough to answer what they were. Does anyone here know? I need to know things like cabinets, and if the official scm50/100 crossover still works.
I know I am kinda hi-jacking the thread, but it is on the topic of using the SM75-150 in a sensible way. And since nobody can really buy the S version anymore we could just talk about my speaker project instead. ^^,
But where to find them for cheap?! On a students budget I will only afford one. Called ATC in the UK and they wanted ~300 pounds for it.
Oh, and ATC is keeping the S version to their own speakers now, I asked them on the phone. So this discussion is pretty fruitless.
I am planning to use my single, mono 🙁 SM75-150 driver to build a ATC SCM50 clone to go with my Krell KSA-100 clone, of which none is of course completed. I happen to have the chinese made tweeters from the ATC SCM16A (still on ebay for $21: "atc tweeter") and a pair of unknown ATC PA75-260 STD 8 ohm (!). Not the -314. Not the -243. Not the -234. But a rare -260. I measued also. 255mm across. It likes to be between 250Hz and 900Hz. They are very revealing. I played it a long time before they loosened up a bit, or my stereo warmed up properly. I was scared the first two days and thought, "what a crappy speaker I bought!" We will see if I can decide on a cabinet for these rarities. 255mm is not 243mm across, like in the original SCM50.
I asked ATC and they didn't have anyone old enough to answer what they were. Does anyone here know? I need to know things like cabinets, and if the official scm50/100 crossover still works.
I know I am kinda hi-jacking the thread, but it is on the topic of using the SM75-150 in a sensible way. And since nobody can really buy the S version anymore we could just talk about my speaker project instead. ^^,
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Solen will sell you both version, but they are more expensive than direct buy from ATC.
I find the price quite right compared to compression drivers and horns...
I find the price quite right compared to compression drivers and horns...
True, true. Good compression drivers are equal in price. It is not like I have to buy the worlds best speaker more than once.
It is interesting that you mention compression drivers. Maybe the SM75-150 is considered to be a compression driver, but I am thinking more of TAD, JBL, BMS, etc, when I think of CDs. How would they fare against the SM75-150? The Avantgarde Trio is considered by many, not all, as one of the finest speaker in the world.
Compared to compression drivers you loose between 10 and 15dB, but you also get between 1 and 1.5 octave lower crossover point.
This is all a matter of compromise, as always...
This is all a matter of compromise, as always...
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I could provide impedance curves of my units (non-super, 16 ohm). Let me know if that's useful. You can easily determine the TS parameters from this.
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