2way vs 3way, same sound?

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Especially if you're over 65! :wchair:
Too true . . . :p . . . but when I think back to peaky (and awfull) phono cartridges, and the nasty HF resonance of some (very popular) condenser microphones, I remember wishing I couldn't hear it back when . . .

The great contribution of the "Baxandall" tone control was chopping the high frequencies first . . . everyone who could hear used to set them a click or two down from "flat" . . . (if you didn't do it yourself it was how you knew the wife had been listening to the Hi-Fi).
 
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What Dave quoted is correct, I have seen a couple tweeters that could be used in a consumer type speaker in my time that could be crossed at 500 hz or below... a couple and Dave mentioned lobing, this normally happens in an MTM in mid frequencies,(I normally use 3rd or 4th order crossed at 2k or below) so to use a first order network, you would indeed need a low cross over point..... I wasn't trying to open a can of worms, I was just saying that the op, clearly stated "using a 1 inch dome".... you won't find a 1 inch dome that can cross below 500 hz.
 
Yes. Because what you are talking about is just the magnitude in decibels of the sound. You are completely missing the TIME response.

Example: speaker A has an on-axis dip -3dB at 2 kHz, but off-axis output is very high. Measures 0 dB at the listening position.

Example: speaker B is flat on-axis at 2 kHz, but off-axis output is none.

The two speakers measure the same at the listening position, but the ratio of direct to reflected sound will be quite different as will the time arrival and smearing of said sound.

Great point!

When I measure the 2 way I've described (1" tw + 6.5"wf) in a quasi-anechoic environment, the on-axis frequency response is fairly flat. The measurement can be considered anechoic because I adjust the time domain window to ensure I'm not including any reflections in the data.The XO frequency is 1.9KHz. The in-room listening position measurement (on-axis) frequency response slopes down but doesn't have a dip around the crossover frequency.

If the 3 way anechoic on-axis measurement is also flat, than in the same room as above, I'd likely have a bump around the crossover frequency.

If that train of thought is correct, it seems as though the 2 way off axis dip caused by mismatched directivities is far enough off axis that it doesn't significantly effect the on-axis in-room frequency response.

Doesn't that mean the 2way will be less sensitive to reflections yielding minimal room to room frequency response deviations compared to the 3way? And therefore there will be less smearing of the sound with the 2way?

Let's assume optimal execution of both designs without taking into account THD.
 
it seems as though the 2 way off axis dip caused by mismatched directivities is far enough off axis that it doesn't significantly effect the on-axis in-room frequency response

you have to consider phasing more on a 2 way (getting the drivers to work in unison), so it depends on the crossover point and sloped selected. With a 3 way it is much easier to avoid phasing problems.
 
frugal-phile™
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Crossover point selection based on human vocal range rather than driver performance is recurring theme, and is poor design compromise.

Driver performance can be choosen to XO whereever one would like.

Crossovers are a compromise, each and every on of them replete with evil. Personally i find an XO right where it is most easily detectable a compromise that i choose not to make.

Tweeter claiming performance down to <300Hz is classifiable as full range

Count the octaves. The same criteria would make the midwoofer in any 2-way with an XO > 1000 Hz a full-range as well.

and will be replete with IMD and break up issues

You are sure? Every driver has some break up issues. There may be more IMD up high, but less than a midbass in a cone + dome in the critical band. And is that measured IMD important? Certainly some other measured distortions in the few studies extant have been shown to be irrelevant (most notably THD). None that i know if that coorelate IMD to sonics. And what do we gain by making the "supposed" compromise to cross this low? No lobing and phase coherence.

With all the compromises necessary to design a speaker, the poor performance of even the best speakers compared to the ultimate potential (i estimate that the best are noymuch over 10% of the way), it is entirely possible to design 2 completely valid speakers that are very different.

Measurements are a tool to help design a speaker. But there is very little understanding of how they those measures correlate to what the ear/brain percieves. In the end what is important is how well the speaker (with all the other kit in the system, they cannot be ignored) commuicates the emotion of the music to the listener.

And the speaker pictured does a very good job of that and at a surprisingly low cost. A clear success. Nitpick it all you want, it does the job.

dave
 
frugal-phile™
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I was just saying that the op, clearly stated "using a 1 inch dome".... you won't find a 1 inch dome that can cross below 500 hz.

He did, my intention was to open things up a bit.

I have heard a couple systems that have 1" domes that XO nicely as 1.2 KHz in a 2-way and even that lower XO makes a difference in those qualities i hold dear. The one that you can actually buy wouldn't be suitable for an MTM thou.

dave
 
Driver performance can be choosen to XO whereever one would like.

Crossovers are a compromise, each and every on of them replete with evil. Personally i find an XO right where it is most easily detectable a compromise that i choose not to make.



Count the octaves. The same criteria would make the midwoofer in any 2-way with an XO > 1000 Hz a full-range as well.



You are sure? Every driver has some break up issues. There may be more IMD up high, but less than a midbass in a cone + dome in the critical band. And is that measured IMD important? Certainly some other measured distortions in the few studies extant have been shown to be irrelevant (most notably THD). None that i know if that coorelate IMD to sonics. And what do we gain by making the "supposed" compromise to cross this low? No lobing and phase coherence.

With all the compromises necessary to design a speaker, the poor performance of even the best speakers compared to the ultimate potential (i estimate that the best are noymuch over 10% of the way), it is entirely possible to design 2 completely valid speakers that are very different.

Measurements are a tool to help design a speaker. But there is very little understanding of how they those measures correlate to what the ear/brain percieves. In the end what is important is how well the speaker (with all the other kit in the system, they cannot be ignored) commuicates the emotion of the music to the listener.

And the speaker pictured does a very good job of that and at a surprisingly low cost. A clear success. Nitpick it all you want, it does the job.

dave

Correlation of distortion to realism of reproduction is very well understood. Irrelevant? Ouch.

Choice of 3" at 350Hz 1st order is yours. How it really performs is easily measured.

IMD that is grossest isn't at the top, it is with the low end sum and difference tones.

Recording playback chain are information transmission system. Noise, harmonic distortion, and intermodulation distortion are primary forms of performance robbing mechanisms.

Emotive sound is possible from wind up Victrola.

I can't be sure about your 3" drivers IMD and break up behavior, but based on multiple measurements of various size drivers, and auralization using multiple drivers with separate tones v with mixed tones make me certain that you haven't done similar experiments.

In a matter of minutes I set up and tested several different size drivers with swept sine combined with 350Hz tone. The smaller the driver, the worse the distortions, and the worse the sound. For comparison, identical drivers set up with fixed tone in one and swept tone in other are compared for IMD free performance. It's night and day.

Designing for fun and pleasure is easy, designing for performance is a discipline.


Regards,

Andrew
 
frugal-phile™
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Correlation of distortion to realism of reproduction is very well understood.

It is? Where are the papers?

How it really performs is easily measured.

No-one has a proven measurement scheme that correlates with sonics... the Harman guys likely as close as we have, but it is crude, disputed by other experts and yet to be independently verified.

I can't be sure about your 3" drivers IMD and break up behavior, but based on multiple measurements of various size drivers, and auralization using multiple drivers with separate tones v with mixed tones make me certain that you haven't done similar experiments.

In a matter of minutes I set up and tested several different size drivers with swept sine combined with 350Hz tone. The smaller the driver, the worse the distortions, and the worse the sound. For comparison, identical drivers set up with fixed tone in one and swept tone in other are compared for IMD free performance. It's night and day.

It is easy to create an artificial scenerio that yields data in one dimension, which may help a skilled designer fine tune, but until it is correlated with what the ear/brain perceives it means little.

Designing for fun and pleasure is easy, designing for performance is a discipline.

If the fun & pleasure are those of the listener enjoying the music (the end use of the process) then the designer needs to be disciplined, skilled, and creative.

A diyer designing to have fun & get pleasure from the execution phase of his project is irrelevant to this discussion and purely in the experience of the diyer.

dave
 
Gross distortion is readily acceptable over no transmission, otherwise telephony and recording would have never left the lab.

Distortion in audio parallels video. Just look at old all analog TV. Harmonic distortion, intermodulation distortion, multi path reflections, all impact picture quality.

Clearly you refute anything written, and can't believe that what occurs in simple multitone experiments translates directly to music reproduction and broadband communication both in theory and in practice.

Regards,

Andrew
 
The "tweeter" i use on the pictured speakers goes down to 100 Hz. XO at ~350 Hz. Bass extension into the mid 30s or lower.

1st order XO with drivers within <1/4 wl at XO so are essentially co-incident. 1st order XO. So they have no lobing, and are phase coherent.

dave

Makes sense if your are into lilliputian sound, thats way too small a driver Dave , maybe if you were to use 4 / ch .....

:)
 
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frugal-phile™
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Clearly you refute anything written

What makes you say that? I learn large amounts from what is written. I avidly seek out anything i can read looking for gems that can enhance my understanding & methodology.

I have an audio library that likely rivals most out there. Hence the request for something toread on the correlation between IMD and hearing perception.

dave
 
frugal-phile™
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Makes sense if your are into lilliputian sound

They produced pretty big sound -- and that in my room which is not small. Many have heard them and will back that up. They won't outdo big horns + big woofers at what they do well, but they have their own assets which those cannot touch.

Believe what you believe... the truth is in the listening. This is one of many valid approaches. Not seen often enuff IMHO.

dave
 
Well I'm going to do a horn system, for fun, to see if it is as satisfying as my little FR basement rig. It will be louder, for sure. Not as rude as the rants that repeatedly show up around here I hope, but maybe. I won't be listening to tones other than Pano's test. OK and low frequency fun.
 
They produced pretty big sound -- and that in my room which is not small. Many have heard them and will back that up. They won't outdo big horns + big woofers at what they do well, but they have their own assets which those cannot touch.

Believe what you believe... the truth is in the listening. This is one of many valid approaches. Not seen often enuff IMHO.

dave

Yes, truth is when microphone picks up input signal that isn't clogged up with >2% distortion products, the listening is much more realistic than when microphone is picking up 6%-10% or more distortion.

Measurement microphone repeatedly reveals gullibility of untrained listener.

Coupled with a tendency to choose louder of two systems, and exposure to loud live sound reinforcement systems, result is high level acceptance of bass distortion >24%, and compression driver systems with distortion >6% covering the rest.

Driver manufactures enjoy working with reduced engineering and build out costs that gullible minds accept. Builders of consumer sound gladly follow suite, and those looking to mine deep pocket status seeking audiophiles have lots of spin to work with.

Clearly not enough real measurements are done by speaker builders in my opinion. So many look at driver data, see a relatively flat published FR, ignore actual performance across applied bandwidth, and conclude with shining success, only to rapidly tire of creation.

Some truly don't care at all about the fidelity of a playback system. If they can hear a familiar beat and a bit of melody their mind takes them on an emotive journey.

You may read, but clearly do not work practical exercises to gain real experience of inverse relationship of distortion and fidelity.

Measurement microphones repeatedly show the gullibility of the human mind. Working with the microphone allows learning, training, and listening discipline.

A real gem of knowledge is easily gained: Take a driver with less than 1% 2nd harmonic listen to single tone in voice range, and then add in 5% 2nd harmonic of fundamental. The augmented sound is louder, and a change in timbre depending on phase behavior of driver may impart an edgy sound, brightness, sense of contrast, and/or other effects. One is truth, the other distorted truth.

Test scenarios are very real. Real drivers, real signals, real results. Hiding poor performance behind masking/distracting effects of program material as interpreted by listener only proves gullibility of human mind, and most certainly doesn't demonstrate distortion as irrelevant to high fidelity transmission of information.

Klippel Listening Test uses similar techniques with program material.

Regards,

Andrew
 
Andrew . . . I'm not quite following where you're going here. We probably all agree that lower distortion is generally "better", that some kinds of distortion sound worse than others, and that there are a lot of bad speakers and undiscriminating listneners out there. Many of us may disagree with the implication that dave doesn't do testing or is unduely "gullible" in his listening (and might question the unnecessary incivility of the implied insult).

It's more peculiar in light of the context . . . you seem to be suggesting that there's something inherently wrong with using small cone drivers over what appears to be their intended range (as opposed to . . . what?) without offering up actual comparative evidence to support the rejection. Do they actually have notably higher distortion (of the "bad" kinds)? Are there perhaps other tradeoffs (and possible advantages) that weigh on the choice? And what are we to say to not-notably-gullible experienced (and sometimes trained) ears who simply say Speaker A sounds "more musical" or "more listenable" or "more true to the music" than Speaker B? Are the preformers on stage stupid and the engineer in the control room not? Or are we maybe still measuring the wrong things, or wrongly weighting the measurements that we've got . . .
 
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