Was speaker shopping and heard perfection...

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#21
Don't know if this is too expensive for you...

Get a used Marantz SA11 CD/SACD player and replaced the capacitors in the analogue stage with Rubycon ZL and replaced the output electrolytic capacitors with film capacitors. Now you will have a first class CD player that probably betters the Krell CD player. Total costs under USD$2500.

Build an opa627 buffer preamp with a good implementation of a +/-15V regulator as the preamp. It will beat most things out there. Total costs under USD $300.

Build a Randy Slone's OPTIMOS or Totem Pole power amplifier with a stiff power supply for around $1000. I had 3 pairs of monoblocks built. Not long ago, I compared it to one of the new Conrad Johnson power amplifiers (around USD$9000? this would be better than a Krell) in a very good set up, and the Optimos equaled the Conrad Johnson in terms of sound performance level.

Now for the speakers. Build John K's NaO mini or any other good OB design for at most a few thousand dollars.

You would get a system that is very hard to beat.

Regards,
Bill
 
#23
Tweeter:

http://www.seas.no/index.php?option=com_content&task=view&id=81&Itemid=105

Midrange:

http://www.tymphany.com/d75mx-41-08

Mid-bass: Custom..10", BUT I suspect you could do even better with a slightly larger driver:

http://www.aespeakers.com/drivers.php?driver_id=11

The crossover is likely a 4th order LR design..(.380 Hz and 3.8 kHz respectively).

PMC utilizes a "straight" line (i.e. no tapering), and typically places their woofer 1/3rd of the way into the line (..with the remaining 2/3rds to the exit). Wall lining is typical "egg crate" foam with some carefully placed poly-fill in the line to act as low-pass filter to remove higher freq.s from exiting the line.

You could determine an optimum line length and "fill" with Martin King's Spreadsheet:

http://www.quarter-wave.com/Models/MathCad_Models.html
 
#26
Graham Maynard said:
Surely a 3 metre line (quarter wavelength ~ 10ft) will be good to below 25Hz ? And lower with some damping fill.
Click to expand...

Of course you are right about the resonance. I forgot to divide by four. Wow what a colossal oversight!

Must be the heat and humidity today 😉 92F/33C, with a 68F/20C dewpoint. No Thunderstorms yet, though.
 
#29
I may be interpreting the illustration of the GB1 incorrectly but it appears to have a chamber above the bottem turn of the TL towards the port, or the port is about tl length/4 from the end of the line. This chamber or volume reverses the slight taper of the line also.
jamikl
 
#31
Tino said:
...Then the bad thing happened....heard a set of speakers at the same store called "PMC EB1" ...No words I have will convey what I heard. ...
Click to expand...

In the bass you don't hear the speakers: you hear their interaction with the particular room, when placed in the particular spot, heard from your particular spot.

I think you heard the EB1's when all three parameters coincided just right.

No chance of replicating that unless your room and placement is identical.

That news will either make you considerably more depressed, or considerably cheered.
 
#33
Hello Tino!


It isn´t impossible the mid is an ATC. The custom version K+H use doesn´t have the characteristic waveguide.
http://www.klein-hummel.com/klein-h...ring_studio-monitors_nearfield-monitors_O300#
The ATC dome really has something special. The clarity of a foil and the neutrality of a dynamic driver. Try to get a listening session with a speaker that uses this driver.
BTW: The K+H active monitor is 2000€ on this side of the pond and is kind of an insider tip in Germany for people who want to have true highend without silly prices.
 
#34
el`Ol said:
Hello Tino!


It isn´t impossible the mid is an ATC. The custom version K+H use doesn´t have the characteristic waveguide.
http://www.klein-hummel.com/klein-h...ring_studio-monitors_nearfield-monitors_O300#
The ATC dome really has something special. The clarity of a foil and the neutrality of a dynamic driver. Try to get a listening session with a speaker that uses this driver.
BTW: The K+H active monitor is 2000€ on this side of the pond and is kind of an insider tip in Germany for people who want to have true highend without silly prices.
Click to expand...


They no longer use the ATC driver (..and haven't for several years now).

PMC was seen as a direct competitor and was denied continued favorable unit pricing ..though the press spin is a lack of driver consistency by ATC.

IMO the best sounding of the less expensive mid-dome group is the little 2 inch usher.
 
#36
bastek said:
The Vifa mid freq. range is 500-6000Hz. The XO points are 380 and 3800Hz. Do you think the Vifa dome can handle 380Hz without distortion?
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ALL drivers distort in one fashion or another. Really though, you would have to look at how it is used in the particular design, AND how the loudspeaker is operated.

At 380 Hz with a 4th order electrical (and something much greater than that as a summed acoustic and electrical), I'd still expect some additional non-linear distortion between 380 and 500 Hz. Could you hear it with a test-tone? - probably. Could you hear it with a music signal? - probably not.

Its a moot point though. Tino thinks he has heard something close to perfection, so at least for him it doesn't really matter (..assuming he used it at volume levels as high as he would ever use them).
 
#37
Hi 🙂 especially Tino (what model of celestion btw?):

I have some ideas for you:

Get back to this hifi shop and put many different sounding cd's : if the speaker is as good it should be able to sound totally different with each cd's. If it has a huge character then it may become dull in long term. 10 K is very expensive for speakers and you should have the best quality grade for this price. If you want this particular sound go for it and be happy, then think to something else, profit.

Like the other pall said : the room treatment and huge space they have in the audio shop is maybe hard to reproduce at your house, you could negotiate a room treatment and complete installation for this price, and also check your bank for credit : life is short get the best while it last.
 
#38
Tino,
your experience mirrors mine of a couple of months ago when I heard the Klein + Hummel 0300s - a powered 3 way nearfield monitor which sells for $5100 in Canada (or a little less if you push). They have in common a 3" dome which I think is part of the key to what is so seductive about the sound. With these speakers the mids are not only really authentic sounding i terms of tonality, but the headroom is more than I am used to - they simply will play louder with less midrange distortion. In the case of the K+H, the mid dome covers 650 Hz - 3.3 kHz and all slopes are 24dB/octave.

You do need subs, though, if you intend to use them in the midfield on stands. That's where the 0410 (the next model up) comes in. It is designed as a nearfield monitor and has almost 3 times the power driving apparently the same mid and high frequency units. I have not heard these but am prepared to believe those that have, that they are in a separate class again. I am in heaven with the 0300s as it is.

P.S. I have heard many of the contenders in this field over the last 30 years and these have something special - and they're not $10,000!
 
#39
Could also look for smaller PMC - they can be 80 % of the sound quality at 1/3 price + same sound signature ; quality....

In your smaller room they will sound bigger like the higher models in the hifi shop and more appropriate than the huge ones.
 
#40
FrankWW said:


Tino, You'll notice that in all the PMC speakers on that page I posted in my previous message how only one side of the TL had foam attached.

That's the "trick". They're using the foam as a multipurpose "acoustic filter" and I expect they had to try a number of different types, densities and thicknesses of foam before they found the one that worked optimally.

(The foam must be glued down thoroughly, otherwise the low frequencies will just worm their way around it and under it and the effect won't work well).

Once they found the optimal foam, and got themselves a good low end - which I suspect is what blew you away - then they had to start the hard work of optimizing the speaker design.

The patent I posted is written somewhat obscurely but I believe there is info in it about the density of the foam that worked for that application. It might be a clue.

I got some speakers and wood together some while ago and cut the wood with a view to doing some experiments with a similar setup but circumstances caught up with me and I never found the time.

However, before you get too involved in researching and building, I suggest again you try to hear Geddes's speakers because if they turn your crank the same way, then they're more accessible in terms of cost, time, and theoretical knowledge.
Click to expand...
The foam does play a large part - I had a set of the origional PMC FB1's (2-way TM) and "upgraded" them to the newer "+" specs, new tweeter (vifa 27-tg35-06) new crossover, and a new piece of foam which sits behind the bass driver, said to "firm up and extend the bass response" the foam was just sitting loose however, not glued in.
I've been a big fan of PMC speakers for some time, having owned the FB1, FB1+, TB2+ and OB1, and am hoping that DIY speakers will yield me better (or at least equal) performance, at a cheaper price, with the satisfaction of doing it myself. My cabinet making is very good, my understanding of acoustics and crossover design is what I'm working on now, I'm still in the lenghty "research phase"

:bigeyes:
 
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