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xrk971

xrk971

Founder of XSA-Labs
Joined 2012
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#1
Off-topic moved from here :cop:

GregB,
I don't equate "DDR" with resolution at all. So I agree with you that expensive drivers when flat can have more resolution. I am not sure how to measure that quantitatively - perhaps it is the dynamic headroom with high SNR and transient slew rate? I have Heil ESS AMT drivers which work from 600Hz to 20kHz, don't need any EQ, are flat out of the box and don't show any ringing in the impulse response. They have superior resolution for detail that I have not heard in any other driver.
 
#2
xrk971 said:
just pointing out the fact the majority of listeners who participated in the "Subjective Blind Comparo" thread preferred a driver with flatter response.
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As pointed out a number of times by a number of people (including yourself when you started out) an effort from which no conclusions can be made, because the ouput of the drivers, at a minimum, are convolved with the mic/recording chain, your room, the fact that it is a 2-way and not a FR, the quality of the delivery media and the system used for playback.

To try to use it as evidence of anything is disingenuous.

dave
 
#4
planet10 said:
As pointed out a number of times by a number of people (including yourself when you started out) an effort from which no conclusions can be made, because the ouput of the drivers, at a minimum, are convolved with the mic/recording chain, your room, the fact that it is a 2-way and not a FR, the quality of the delivery media and the system used for playback.

To try to use it as evidence of anything is disingenuous.

dave
Click to expand...

My thread is not the only thing that says people prefer flat response curves. It is a well known concept from early works on psychoacoustics and is the reason why manufacturers of speakers aim for a goal of a flat response curve. The fact that the drivers in the comparison are all tested under the same box, same room, same source, same recording chain with the only variable being the driver, isolates perceived differences to the driver for an even comparison. I think it's better than someone's subjective description. First I had a thread that discussed the objective differences through measurments and you objected that that is not accurate way of showing what driver sounds better. Then I had a thread where we let Diy audio listeners decide what sounds better, and you still say it isn't good for deciding what drivers sound better. I guess we all just need to go back to trusting what folks with Golden Ears tell us what drivers we should buy based on opinion of one person.
 
#5
planet10 said:
Then you are making up a different definition for something that has recently been well defined. It is the lower limit of a device's dyadic signal-to-noise ratio… ie how well a device does at passing very low level information and not burying it.

dave
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Please cite one peer reviewed piece of scientific or engineering literature that defines or uses DDR for audio sound quality.

I think we have been down this path before and I don't want to keep rehashing it. I think Barleywater summarized it here:
http://www.diyaudio.com/forums/full-range/270094-objective-comparison-3in-4in-class-full-range-drivers-23.html#post4234206

I don't want the OP's thread to get shutdown like some other threads.
 
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#8
xrk971 said:
Please cite one peer reviewed piece of scientific or engineering literature that defines or uses DDR for audio sound quality.
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Perhaps not that specific term, it is only 20 years old, and has not been in widespread use, but we are talking about the lower limit of a device's dynamic range, specifically in dyamic situations (ie with music as opposed to the static sine wave stimulus usually used to measure it) something that has been in use for at least a century.

dave
 
#9
I've never had an op-amp based phono stage sound as "detailed" as say a current source 12sl7 hybrid with passive RIAA and a simple anode follower buffer. Is this analogous to the speaker situation? It could be argued the tube preamp's noise and/or microphonics are adding the sense of "detail" - My hearing is in crummy shape compared to many so levels need some elevation. Is there an unbiased way to compare two speakers for this property which is alleged not to be connected with simple frequency response? Could a recording of speech played in a quiet room at very low levels be recorded for intelligibility comparisons? Behringer makes or made a little monitor with passive crossover which measured quite well - but imo wasn't very good.
 
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#11
IIRC, op amp based phono stages with vinyl medium in general subjectively (in comparison to good tube): flatten the depth perspective, homogenize timbre across all instruments, and sound "darker" in tonality. This is worrisome as op-amps are universal building blocks for mic preamps, output stages, etc. Of coarse, tube-transformer combos may have issues too. FWIW, I tend to prefer simple 3 transistor phono stages to op-amp based type.

are there mechanical characteristics which indicate the potential of good DDR in a loudspeaker? - such as very low moving mass in the coil and spider assembly? - how do paper formulations matter? how about the surround type and damping? Cone profile? There must be cookbook rules and cherished "recipes" known to some transducer engineers.

although vinyl lps are limited in absolute dynamic range, there are plenty left made before solid state so those might be a type of reference.
 
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#12
freddi said:
are there mechanical characteristics which indicate the potential of good DDR in a loudspeaker? - such as very low moving mass in the coil and spider assembly? - how do paper formulations matter? how about the surround type and damping? Cone profile? There must be cookbook rules and cherished "recipes" known to some transducer engineers.
Click to expand...

I am sure that there are, but everyting is interrelated, everyting counts, and there are so many options (ie think of how many ways to make paper), and with no way yet to fully quantize performance that it is still an engneering based art where experience really counts.

dave
 
#13
what happens in multi-way, particularly coaxial woofer + compression driver? - is DDR typically greater or different for the treble section than the woofer? is DDR such a subjective term that its a matter of opinion at this point in time assuming two speakers measure relatively close in response with similar polars.
Can an op-amp circuit be tweaked/tricked to mimic what I hear in "good" tube phono sections?
 
#14
freddi said:
what happens in multi-way, particularly coaxial woofer + compression driver? - is DDR typically greater or different for the treble section than the woofer? is DDR such a subjective term that its a matter of opinion at this point in time assuming two speakers measure relatively close in response with similar polars.
Click to expand...

It is likely that the different devices will have differeing DDR, and even that a single driver will have different DDR at different frequencies and that it is different with different music playing thru it.

I know of no way to measure it objectively -- we still use static/artifical stimulation forgross FR measures. We can think of the latter as measuring the shape of the surface of a body of water under still conditions, and DDR as the bottom of the body of water, with the dynamic range as the depth. Dynamic conditions *** having to deal with waves.

Can an op-amp circuit be tweaked/tricked to mimic what I hear in "good" tube phono sections?
Click to expand...

I think one has to consider the maxim that once the information is lost we can't get it back. Good tubes, despite their inherent issues, are still the best amplifying devices we have come up with yet so they start out with an edge. Clever design & new devices are bringing solid state devices closer alll the time.

dave
 
#15
planet10,

Why continue DDR stuff you got no paper yet and can't you just call it micro detail until then, until you get a scientific paper on micro detail may i quote what Barleywater said "QUOTE" DDR is a thing. Dynamic range is straight forward "UNQUOTE".

Over that thread http://www.diyaudio.com/forums/full...d-alpair-10p-7p-tang-band-w8.html#post4285040 planet10 can mention DDR at post 7 and it stays, xrk971 comment post 7 as a post 10 and end up here why this unequal weight who can speak opinion of micro detail.
 
#16
Micro detail, inner detail, detail, resolution, all sorts of other favorite terms have/are being used to describe the same thing. I use the term DDR as it ties the concept to a well-known related measurement and hopefully makes people think about it and hopefully lead to a way to measure it.

I can use whatever term i like… the lousy-goosy subjective only terms don't do it for me.

You can use whatever term you prefer.

dave
 
#18
I just fell into this thread so maybe what I am about to say has already been covered - if so, forget it.

A speaker driver is a passive device and therefor, if not powered, or powered with a zero signal, cannot produce any sound o noise by itself. That means its lower DDR limit is zero. Logically, it makes the DD infinite - the ratio of 'something' to zero is by definition infinite.

So as several others here have posited, it's really the driving electronics and all that is involved there that establish the (non-zero) lower limit, and speaking of a DDR of just the driver in itself seems not to be anything useful.

My € 0.02 worth.

Jan
 
#20
Jan, in an absolute sense, that's right. No signal, no sound. But I doubt it's what Dave has in mind. 😉

Once a speaker cone does start to move, what is its self noise? Does the non-linearity of the cone and suspension get in the way of the small signal? Is there a threshold at which the signal swamps the noises of the driver itself?
 
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