PMC vs. ATC

Inpeices;

Because Brizon keeps dragging this out after he calls his friend who knows about speakers. It be nice if he would just come out and say what he has to say.

He keeps ducking in and of this technical to neophyte wording which likely means he's calling a friend to help him because his concepts are correct but his symantics are NOT TO THE LEVEL OF HIS ARGUMENT, so my hostility is to his wasting my time. But then again I am sitting for my nephews so I'll waste his.

"I have sign have a slight rise in anachoic conditions which equates to a treble peak in real life when reverbation in a real listening room is considered."

Sign? And you can't have recent ATC anechoic measurements you BS fabricator.

Treble lift, so PMC puts a dip in their response to anticpate this? My opinion of PMC's design team is slowly sliding down the respect scale due to your rhetoric(maybe you'd like to disclose the frequencies this phenomena effects typically) in room versus anechoic behaviour, is highly dependent on room acoustics as is bass lift which can be an enemy of a T-Line as most rooms will add gain significantly below 40 HZ, you don't want a speaker flat to 20hz because it will end up +12dB. So it doesn't make much sense PMC would compensate for treble lift and ignore room gain? But in my room measurements show no lift except a tinge around 14khz but I don't know if that's the tweeters normal response in the treble in fact it is the tweeter which rolls off at about 12dB/octave starting at 16khz that mainly gives us the +/-1 variable. But that is likely due to the diffusive room treatments I have. So we go along, your experience versus mine. IF you're in the UK maybe its the humidity that's making the difference?

It be nice to see how the PMC mid stacks up against the ATC mid in 2005, call your friend and have him serve up the data, I'll get some from ATC. The last time I compared it was 2001 and the PMC was slower but appeared to be slightly better damped which will make it smoother sounding. But you already know that, well maybe you don't because you said impulse response was irrelevant. The MB2's were more dynamic (bass) but not as coherent as the ATC's. Most of my PMC experience recently has been with the more ordinarily priced speakers so forgive me for talking about a 4 year old memory but I did have them in my house for a month or so, I think I got the best out of them and their best was absolutely outstanding.

BTW Voicing is not a scientific term its a term used by speaker designers who can't get right so they fudge or change their speaker so they can sell it. I'm a salesman so I know these things. Do you have an issue with the 4th order crossover used by ATC, personally the integration on my 150's is flawless, not ripple to be heard not a ripple to be seen, the mid does have a little bump but that could be mic positioning and the like. Maybe you info is flawed? I know what I hear and the 150's play all my CD's just fine no glare or harshness a little more forward when played in two channel but I listen in trifield so that isn't a problem

Sharp is not a technical term, sharp is caused by distortion whether it is amplitude or unwanted modulation. maybe you guys talk that way over there, like bonnet etc. So we may have a semantics problem.

Your comments on T-Lines, they load the room better is technical?, is incorrect unless you mean easily more boomy. they do not present stiffer impedance than a sealed box it acts just like a sealed box over most of its frequency. 2pi loading is better and more manageable in room it creates the least modal problems, what were you talking about, what does your research show Brizon? Most of the superiority is not proven its opinion and its superior for the application those designers intend, I prefer to use subwoofer where you have T-line output, so for every positive there is a negative, my opinion I like sealed boxes the best with impedance correction, I build my subs that way and for domestic use I try to only get my speakers flat to 50 hz because bass and midrange need to be in seperate places to "load" the room properly. I use a T-line type cavity to remove the resonant energy from the cone in one of my designs , but having air coming out of a tube is one more variable I do not welcome, . See we have different philosophy's maybe we can compare speaker designs?

See we are talking about ATC and PMC, neither of which have text book loading, but I don't need to tell you that which is why they outperform the more pedestrian offerrings from other companies. To lump ATC with B&W just shows you have an axe to grind and objectivity is beyond your R&D mentality, you should throw PMC in there to then with B&W, because all they have done is shined up pro models for home use and how about those Bryston amplifiers, I guess they're a bunch of sell outs too like ATC. You act like PMC is so different, but I don't see it and you have this attitude like you're fighting uphill against the industry leader (like I do, carrying PMC, Meyer, DALI, Blue Sky and ATC does not make you the most popular dealer, trust me) like ATC as if they don't deserve it. But the fact is JBL is probably the industry leader and ATC and PMC are in the same fight against them.

Your supositions based on incorrect second hand knowledge about what ATC is trying to do are not facts to rebbutle they are just some time wasting topic spinning BS you made up. The things you discuss do not relate to the 50's,100's and 150's. 7's 12's 35's yes.

BTW go to www.theavarchitect.com and you can see my 150's now one thing I didn't think of was that they were specially built for an AES Sony SACD demo, so maybe they differ from the run of the mill 150? That I do not know. But the 50's I have measured seemed similar through the treble and were tocu analytical due to the lack of bass afforded by the 100's and 150's.

Usually I'm not discussing two excellent speaker systems because a person smart enough to buy PMC respects the ATC, which I think I had to drag out of you under one of your pretenses that the ATC's 50,100.150's are desk monitors...Whatever. You are different and in the end you are the one who is the salesman but you won't disclose it.

Whoever you look to for guidance in what makes a superior speaker differs from mine in their philosophy. And that's ok.

Like I said I wanted you to temper you comments and you did, maybe in the UK? ATC is a big dog marketing driven company, but here in the US it is much different.

"You have no idea how much R&D I have done thank you," well saying that means nothing to me why not say I have 20 years R&D experience? When it comes to audio I KNOW you have little experience or it was wasted experience while you got paid for it, or you have been unfair in dragging this out.

Later,

Hi. Another supposition! You assume I have a friend who knows about speakers - because otherwise your "story" about me just doesnt fit. Well sorry to have to tell you this but you are just plain wrong. I did this all alone and unassisted. What's more it was easy ;-). All you can do is make false assumptions and sling labels hoping they will fit as you have no technical argument to fall back on. All your suppositions are contradictory - you are just clutching at straws hoping something will stick. Consequently your remarks about my not coming out and saying what I have to say are so bizarre as to be inance beyond any hope of my making a sensible answer to such nonsense. I have clearly surpassed your presumptions about my level hence your need to invoke an imaginary speak expert who is whispering in my ear. Come on be serious. Do you think I am calling pmc or something?? I have no connection other than the speakers I bought.

I didn't temper my comments - if you read carefully I have not backed down on or moderated a single claim. If you beleive I have then show me which one.

As for my semantics they are perfectly sufficient and accurate though for truth I was dumbing down the concepts somewhat until you proved that you were taking things to a higher level. Please show me exactly where I was ducking in and out and I will be happy to clarify.

As for the atc measurements I have seen such on numerous occasions and you yourself admitted a treble peak of 1dB broadband!! Given that we both agree this fact then certain physical laws lead inexorably to my conclusion. You are hoist by your own petard. If I was fabricating "BS" then it's the same BS you also produced. I happen to know something about anechoic chambers as they were necessary for research work I did many years ago. No need for an imaginary expert - I have a research engineering phd and my own expertise is quite sufficient. Specifically I worked in speech recognition and monitoring systems - nothing to do with audio or sales but an area of engineering which distinctly overlaps in a lot of ways. A lot of use of anechoic chambers and frequency response measurements for speakers. So I know what reproduces human voice best and it is PMC not ATC - voices just don't sound the way the atc presents them tonally. Or do you still think I am a junior salesperson??? Given you have corroborated my assertion from your own mouth then surely the issue is beyond any contention.

People don't listen in anechoic chambers and the design should reflect this. The same as a speakers anachoic bass response does not match real world siting as you noted - so it is with the treble. ATC themselves rely upon rear wall reinforcement - this is a strengthening of lower bass response that would not be present in the anachoic measurement. However they factor it in for real world performance. That is just good engineeering practice and applies to the treble as much as the bass. No-one says you have to cut the treble but a reasonably directional tweeter and a flat response rather than a peaked response would be a good start. Got it? PMC are hardly dull sounding they are still brightish due to the FLAT response. In a treated room their inherent neutrality would be more apparent, just as it made the atc treble more palatable, though not quite neutral still due to the treble lift under anechoic conditions.

Sure you have to be careful with a TL - you need a big room I don't dispute that. I keep mine 2m from the rear wall and 1.5m from the side walls. Problem solved. Yes likely in a smaller room atc might sound better due to bass room interactions. However given a large enough room the TL will give much better results. Again I point you to the issue of acoutic impedance matching to the air mass - sealed or reflex boxes just can't compete. If you have technical papers that claim otherwise I will be happy to view them. In a large room with appropriate positioning the TL will give a flat response to an appropriate level and will do so more effectively in terms of dynamics and detail than a sealed box or reflex design. Which is exactly what I heard. There is no isssue of pmc ignoring room gain. You are off on a flight of fancy.

The issue here is the treble response not impulse response.

You claim to KNOW beyond any shadow of doubt quite a few things about me - many of which you have already abandoned as they proved to be wrong. You then move onto the next guess you absolutely KNOW is right. :S

"Voicing" is a non-technical description of interpreting test measurements in order to engineer a flat frequency resposnse taking into account room effects. Just a colloquial way of descrbing the R&D process. Happy now? ;-) I used these non-technical terms so as not to alienate other readers by trying too hard too look like an expert. Likewise with "sharp". Stop nitpicking it is irrelevent and petulant. We are not pretending to be hifi designers here. At least I am not ;-).

I suggest you read a techical book regarding TL, the theory is pretty clear - I have explained the issues but you don't seem to have grasped them. They are only boomy if poorly implemented or sited. It is very hard to make a good TL so usually sealed box or reflex is better implemented. However the failure is implemtantion not fundamental theory - and PMC have got it right. They provide a better match to the air mass of the room - that is established fact and the theory is outlined in even the most basic texts. The back pressure on the bass driver also improves control over the bass effectively as if it were increasing the damping factor of the driving amplifier. We can discuss amp design as well if you like - all my electronics is currently being converted to DIY kit - eventually only the speakers and turntable wil remain and I will convert the PMC to active using diy active crossovers and using my own in-room measurements. I am sure the atc crossover is very good - it is only the treble peak I take issue with. It's a preference not a flaw of the design. "Sharp" refers to a treble boost nothing to do with distortion. I think the PMC sounds cleaner myself but I think this is a knock on effect into the midrange of the TL driver.

The PMC midrange driver spec is not in the public doman so far as I know as it is an in-house design. contrary to your beleifs I don't have inside access at PMC. Nice try to trap me but no good I am afraid.

Your sub idea sounds good - it will doubtless work well when room size is limited. I have a huge listening area so I don't need to consider it. I have not observed any particular modal problems (except for one piece of organ music) so it isn't an issue for me. So long as you just use the sub low down and don't intefere with the mid then it's a good idea in principle.

I don't lump atc with B&W - atc are much better. I just don't like listening to either of them if the truth be told. I have no axe to grind why would I? You seem to think I have a vested interest but I do not. I found that atc and pmc sounded very different to me. Doubtless each excels in some areas relative to the others and maybe you prefer that designs compromises and I prefer PMC. They are designed for different things and their different tonal balance reflects that. For me tonal neutrality is the most improtant thing. I am certainly not dogmatic. I like bryston amps. However I prefer the older ST series - the SST range don't do much for me. So maybe they have sold out ;-). Maybe PMC will too. If soemthing better comes along I will happily buy it. If that happens to be ATC then all well and good. FYI most of my comments apply to the 100s.

By the way - which pmc models are you actualy talking about? My comments are restricted to the larger three way designs like the MB2.

Hey brizon,

Well I don't doubt we could swap systems and go on enjoying ourselves, I'm glad we (I) had a holiday weekend to sort this out.

All do respect to what you were saying, I get it now but you were talking like two people, and I appreciate you dumbing it down but to me it was deceptive (not intentional I know) I wanted to have a discussion not a fishing expedition :). Look if you studied speech intelegibility then let me know, part of my film degree (25%) of my classes were devoted to speech intellegibility and "noise" in communication. I still study it today, independently. I was just fishing to see who you were and I must say, the combination of semi-promotional speak (fastest growing speakers...on the back of domestic sales) SOLD!!!!, words like sharp and etc, with an obvious clear understanding of how things work, I'm like "who is this guy can I go here, lets poke him and call him a tourist if he's educated I'll get a response!" I knew you were playing me, So I kept poking you with those crazy SUP's and traps so you'd tell me to clarify my petulant ways. :)

Hey check these out, these kind of support my argument but they were the only ones I could find if you can direct me to others I want to see because the speaker is what it is and I can't change what the ATC is and You can't change what the PMC is....so i'd like to know what I can.

http://lib1.store.vip.sc5.yahoo.com/lib/transaudiodirect/65
eratc.pdf, "this is kind of sketchy I know."

http://www.guidetohometheater.com/speakersystems/5/index5.html

I have a new mic preamp coming in and when I get it if you're interested I'll take some measurements of my 150's and I'll run them through the psychoacoustic filter and compare the straight in room response, take a quasi-anechoic then with the psycho-acoustic filter see what we get.

I must admit that I took sharp as more of an adverb and an adjective, or a dynamic problem. So that's why I jumped to impulse response or IMD because I assumed if it drove you from the room it had to appear by surprise not as a consistent character or you wouldn't have played it that loud. LOL! But maybe I'm taking you too literally.

Fact is after all this we still disagree on magnitude and I still percieve your hearing like the Princess and the Pea :)....still, I guess it is what it is. Thanks for the kind words on my sub design and since I work typically in 8X12X3 meter rooms max, you understand my philosophy.

I sold the Bryston St series the SST's seem a bit softer, that's probably because so many speakers are sharp...I guess that's the best way to go to catch a few more flies if you're building amplifiers these days.

Have a good week. look forward to chatting again hopefully more constructively now that we know each other a little better.

I had MB2's, Those are the only big three way PMC's I have heard.

Doug

PS: "The PMC midrange driver spec is not in the public doman so far as I know as it is an in-house design. contrary to your beliefs I don't have inside access at PMC."

Actually it was wishful thinking. I'm a curious dude when it comes to these things ;(

Haha thats ok, doubtless having a treated room makes the top end quite a bit more palatable. However this is something usually only studios or very dedicated individuals can commit to. I rent so it's not an option for me. Most rooms are very reverberent in the Uk due to wooden floors and even with carpets the treble just gets too strident especially with small rooms.

My first research job was working in speech recognition systems of which testing things like hearing and speaker systems is a very important part. One of the things I looked at was computer speech recognition in high noise and distortion environments like fighter cockpits. I then moved into RF engineering which also involved listening tests for radio intelligibility. I then went into nonlinear signals processing and analysis before jacking it all in to work in finance 5 years ago. My interest in diy just comes out of the fact I am interested in everything technical.

I have also rountinely had to have my hearing tested up to 20 KHz. My hearing extends flat past 16 kHz which is extremely unusual in a person of my age. I often find I can hear high pitched sounds that others can't and this is partially way high frequency treble boosts annoy me so much. To others they probably dont care. The person who complained the most when I took them to atc dems were female. They usually have better high frequency hearing too. She actually liked hifi (especially if it was big, bulky and black!) so she wasn't just petulant about being dragged in. ;-). She liekd the pmc best and I managed to convert her from cd to vynil in that dem (she thought there was soemthing wrong with the cd player initially!).

Are you using active crossovers with the atcs?

Nick.

Im impressed!