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Propeller Head Plaza Technical and scientific discussion of amps, cables and other topics. |
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Propeller Head Plaza Technical and scientific discussion of amps, cables and other topics. |
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In Reply to: Re: Coaxial dipole posted by Donald North on April 11, 2007 at 22:26:45:
DN - I recommend you read some of Robert Greene articles. He seems to be a pretty smart guy, not to mention mathematics professor at UCLA and also a musician.I just started to. My apologies for not knowing who he was, he measures and listens. I will certainly pay him more attention, although I will still regard that magazine more as The Absolute Nonsense, than anything resembling readable material.
DN - My personal paradigm for a loudspeaker system is to reproduce the original recorded signal with minimal influence from the room of the reproduced sound at the listening position.
A worthy position. I'll use unavoidable room influence to enhance the illusion that I am not listening to loudspeakers or a recording.
DN - How did your speakers sound when you listened to them outdoors?
Like pink noise:-). I'm waiting on the recent rains to subside so that I can attempt a crude experiment. An H-frame with a single XLS Peerless and an identical size sealed box with 2 XLS in dipole configuration. To be listened to outdoors (on the ground) at equal radial distance about a foot apart. Mainly test tones, but maybe some (bass) music too, to see if I can hear a difference. John K is of the opinion that at subwoofer frequencies, it is the radiation pattern, not the unimpeded rear wave that determines the aural characteristics.
DN - You ask many questions about my Sequence speakers. I'm not prepared to answer them all at this time, but have investigated each and every issue you mention. Here are a few comments:
1. The CSD on the midranges is excellent on a baffle and in the enclosure. Linkwitz himself liked the HDS variant of the driver and spec'd it into his Pluto system until they were no longer available. I purchased quite a few for my Sequence model.The Peerless composite cones were my favorite non-rigid. I've owned a pair of the HDS5.5's like Linkwitz used since about 2 days after Madisound first introduced them. 1999? Used them with a D25AG35 Vifa in a little desk top monitor circa '99.
DN - 2. The distortion on this particular driver is very low as I personally measured on a B&K 2012 and Listen SoundCheck system. Use 4 together in unison and the distortion is further reduced.
Distortion is frequency dependent and involves the motor as much as the cone, as you well know. Would distortion be lower than a W18 anywhere but near the resonance peak frequencies?
The one question I would like you to answer as a driver designer, is
Why does a highly lossy medium best preserve signal integrity and minimize signal distortion?
DN - 3. I have laser scanned at AuraSound many high-end 5 - 7" midwoofer transducers. ALL (paper, plastic, metal, carbon fiber, honeycomb, etc) begin their bending modes below 400 Hz. Some drivers behave uglier than others with increasing frequency. No cone driver that I have ever encountered and tested is a rigid piston in the midrange. A rigid metal or ceramic dome midrange might.The question is which will act more like a rigid piston, not be a rigid piston. Soft cones need not apply here.
DN - 4. I recommend you and others read some of Harbeth's investigations into the behavior of cone materials versus frequency.
I will. Although I have never heard a Harbeth that I would even consider decent. Just another box with vertically aligned, uncorrelated, uncontrolled directivity drivers. Yuck/yawn.
DN - 5&6) I'de still like to know how sound re-radiation from the box through the thin cone is addressed. Also, the off axis data will tell me how much comb filtering will occur from the uncorrelated drivers. Higher XO = higher wavelength separation.
DN - In the end what matters is whether one likes the sound or not. I have no dealer for the Sequence back east at this time, but you're welcome to hear them in Los Angeles.
But of course. Much like you favor tubes, for me, listening to non rigid cones is like listening to a speaker with a veil in front of them. Even if they (rigid cone/low distortion motor) reveal the poor sound of a recording, I know that logic dictates that one blames the recording, not the speaker.
I'll keep an eye out for the NRT coax and pray that its an aluminum cone :-). If I'm ever out that way, I'll drop in for sure.cheers,
AJ
The threshold for disproving something is higher than the threshold for saying it, which is a recipe for the accumulation of bullshit - Softky
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Follow Ups
- Re: Coaxial dipole - AJinFLA 18:58:26 04/12/07 (1)
- Re: Coaxial dipole - Donald North 22:38:40 04/12/07 (0)
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