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It is currently 15 Sep 2019, 10:15

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PostPosted: 03 Jan 2019, 21:43 
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Joined: 04 Jun 2008, 20:59
Posts: 4023
Location: Arizona, USA
Hi Everyone, To start off the new year I thought I would stir up the pot a bit. I spent a goodly amount of time this past month swapping around components between my turntables (but not the rest of the system). A lot of listening time as well. It struck me that what I finally settled on (at least for now) was the following...The diy turntable made from the drive and control circuitry from a Dual 701 direct drive TT, the Jelco 370H (9.5 inch) tone arm and the Grado Sonata II moving iron cartridge. This feeds one of my diy "Groove" phono preamps into a passive digitally stepped (relays) volume and input selection line stage, then off to a quad of Oddblocks using KT120s set up with EL34 parameters. Then into a pair of Martin Logan ESLs with a pair of 200 L subs with Altec Lansing 30cm drivers.

With all that out of the way... Ignoring the quirks the audio gear introduces (a subject all its own) I came to a conclusion that really as good as everything is there are inherent flaws. For one, the room is way smaller than the actual studio or concert hall the music was originally played in. The acoustic signature of that is impossible to reproduce accurately. Second, also because of the room size and shape new resonances and nulls are created that are not in the original material. This can be handled moderately well and I do so with various acoustic treatments (diffusers and absorbers mostly). These two thoughts led me to some conclusions about how I personally like to hear reproduced music. Speakers come in generally two kinds, direct radiators and di-polar ones (aka bi-polar). Each adds it own type of flaws IMO. Direct radiators are good at imaging, but again IMO not so good at spacial rendering similar to concert halls and such. (please don't all get bent out of shape on this....). Good ones in good rooms, well set up are really nice. Lessor ones and not so great set ups...well ...). ESLs and other di-poles tend to not be as great at point source imaging as a large part of the sound is radiated to the rear. They are fine for central imaging, just not to the sides. This can be managed, but not totally so with careful absorbers, diffusers and physical positioning including angling and tilt. IMO they can not equal the point source of direct radiators for non-central imaging though. Di-poles do however convey a much more enveloping space. The sound stage is far wider even if artificial, and the multitude of reflections from the rear and to some extent sides convey a bigger sound wall.

So after much use of both types of speakers, my personal choice is the di-pole for everything above the very bottom octaves. Is it musically accurate, nope, but I feel it is a better rendition of the intent of the artists. So what do you all think? Disagreement is fine and encouraged as long as it is civil.

Good listening

Some of my DIY Tube Amplifier Projects:

PostPosted: 19 Mar 2019, 12:33 
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Joined: 05 Aug 2016, 14:35
Posts: 227
First of all, no matter what sort of components you use at any level at all, what you reproduce in your listening area is, at best, and then only perhaps, the third cousin of the actual live performance. Where the actual experience lies on the curve from actual blood relative (third cousin) to passing acquaintance - the individual dating that third-cousin - includes many factors from where the original performance took place (Studio, concert hall, club, stadium, open air), to the miking to the engineering, to the recording, even to the medium on which it was recorded. And that is before it reaches you.

Now, making sound is about moving air. Air has mass, and requires energy to move. Accuracy aside, consider the amount of air being moved by a full symphony orchestra, the space in which it is being moved, the footprint required to provide the movers and all of that. All of which is being captured by a dozen-or-so microphones, then mixed down to two (2) channels after some level of processing. The engineer is making choices every step of the way in that mix-down. For giggles, let's assume that we are adding a pipe-organ to that mix - with Bombard pipes making 30 HZ. Take that home (Saint-Saens Organ Symphony).

Now, am I correct in suspecting that you are bi-amping each speaker-set with a pair of ~25 WPC-continuous Class A amps?
And, if I remember correctly, your speakers are ~91-92 dB @ 1 watt?
Some other basics: The transient associated with a snare-drum rim-shot is 120 dB.
The Peak-to-Average (P/A) of a well-recorded Saint-Saens organ symphony is ~30 dB.

Now, ambiance: Your room at home is not a concert hall, nor a studio in volume. However, neither are you trying to make concert volumes. You are trying to make sound that will fill your room with about as much energy per cubic whatever as that concert hall or studio. A much less daunting task. And, you are trying to make something-like-live volumes. And you are trying to maintain/duplicate the same dynamic range - approximately - as that concert hall or studio. I would suggest that the studio discussion be tabled in any case as that is a venue not designed for listening, and is as artificial in its own way as your listening room. Make it a club or small venue with a live audience.

When you are in a live audience, there is no 'sweet spot'. What you hear is a continuum of sound from one corner to another, from the front row to the last. And it is that experience that differentiates live music from reproduced music. Most recordings are "miked" from the virtual 10th row-center, with admixtures of instrument-specific signals.

Hence the "third-cousin" relationship.

In my inventory, I keep very large Maggies, and then a range of speakers from fully restored and upgraded AR3as through similar Dynaco A35s. Our main listening area is 5.2 x 7.3 x 3 meters and quite 'live' in terms of plaster walls, hardwood floors. a good deal of glass and so forth. The Maggies in that venue require my most powerful brute-force amp (solid-state) to make any sort of reasonable noise. And none of the other speakers will begin to fill that room, even the big ARs. But with that amp and in that space, the sound can be quite stunning. But still not the Kimmel Center, or even the Academy of Music. Without knowing the size and nature of your listening area, I will not comment on the components you enumerate.

Bi-Polar vs. Direct: Mixed bag here, and entirely, 100% dependent on how the speakers are placed. I am blessed with a wife that allows me to place my Maggies where they want to go, not where they are at their decorator best. Meaning that I am able to exploit their bi-polar nature to the fullest. Which means that even in a 'live' room, I have no need for room treatments other than some basic constraints on placing the furniture. Angling the speakers, distance from walls and corners and such handle _ALL_ the other concerns. Which results in a rather broad sound stage, yet retains the illusion of instrument location - with closed eyes, one may follow each section or instrument and where it is on the virtual stage. Yet, that triangle transient, Beethoven 9th, Ode to Joy, is right there, back in the percussion section, yet clear as the next seat. All of that, and an amp with less headroom - may as well be mush.

Using the ARs in a smaller room, I can get the same general effect, but a smaller sound-stage and a bit less locational clarity - again due to the narrower sound-stage.

Now, the difference between Accuracy and Precision. That thermometer that reads in whole degrees only, but is dead-on, is accurate, without being very precise. That thermometer that reads in hundredths of a degree but is anywhere from 1 - 6 degrees off, is quite precise, but not very accurate. You are looking for an accurate translation of a musical experience from the performance venue to your listening venue. NO MORE than that. Want an example: Aristophanes: The Birds. When the father of the first bird died (before the Earth existed), his daughter buried him in her: Original Greek: Crest. English Translation: Tail feathers. Original Greek - aside from a character on stage: "And that is where Kephale got its name (a town in Greece, Kephale translated as "Head")". English Translation: "And that is where Asbury got its name". An accurate translation including the pun, but not hardly precise.

Bi-Polar speakers are tough to place - and trying to correct for their needs via room treatments is a fool's game. If you have the option to work with them alone,. and giving them sufficient space apart to really show off their capacity - go there. And, as a strong suggestion !!-DO NOT-!! start with them on the short wall. Start with them on the long wall. You might be very pleasantly surprised.

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