ShinOBIWAN said:
Thanks for the clarification, but my intent was to do just that - compare with what else is available in order to decide what components to use in a hi fidelity system for the home.
🙂
Pan said:
Peter, measurements are not opinions. I go by measurements and designs that others have done because I'm not an expert at either.
Yes, my motivation is low distortion and yes, I'm not good at reading graphs. So with the help of others who are far more knowlegable I'm able to make decisions, bracketed by my budget of course, about what to build.
sdclc126 said:
I'm not.... and I've made a bunch of them.
The problem, is that most of them you see are "marketing numbers". Also... one measurement does not a story tell. Audibility is complex so you really have to look at a range of measurements to get a complete picture.
The reality is that most people don't know good ones from bad ones. Earl is spot-on not to trust other people's measurements. I don't either...
Pan said:
Peter, what sdclc said about the Accuton tweeter has a point if we want to use Zaph's data to back it up.
His HD sweep measurements were obtained using half-way nearfield mic. SPL is equivalent to 90 dB at 1 m---a realistic level in normal listening.
According to his data---I want to avoid confusion---, the Accuton C23-6 ceramic dome tweeter is an excellent performer. Very low distortions in all frequency except a little high 3rd order hamonics below 2 kHz.
But is it worth $225 if we only want to focus on the distortion performance? I do not think so. Again, according to Zaph's data, there are several, much cheaper tweeters that are on par with or even outperform in some frequency ranges the Accuton (e.g., Peerless 810921 and Seas 27TBFC/G).
I'm pretty sure that's what sdclc meant.
Kevin Haskins said:
I generally agree. But as you implied, it depends on whose and what kind of measurements. If we know the details of the measurements (i.e., exactly how they were obtained and precisely what they mean, etc), we can trust them (of course, assuming that the data are not fake.)
"In post #193 to Robh3606, I wrote
I agree with you about an SPL contest. But this thread is about our experiences with home hifi, and I've pushed my home hifi to live/stadium levels and got better-than-live results.
But we haven't agreed on what is "high SPL"."
Hello Eric
To me high SPL is average levels into the upper 90's for a home setting. I usually listen in the mid to upper 80's range depending on the source material.
For a live setting 105-110 peaks are a good day. I have taken SPL meters into venues and had them peg at 116db and just stay there. That was a run for cover show. I always have ear plugs handy as you never know who's on the board, how much compression they will be using and if the guy running the board is hearing impaired or not.
I have never heard a single pair of commercially made speakers, short of horns, that could match some of the SPL levels I have been exposed too going to live events.
My larger speakers I was using as a comparison to the XPL clones are JBL 4344 clones. Those are 80's vintage monitors. The real deal, bandwidth limited 4 ways, compression driver mids and ring radiators up top. They are relatively efficient 93db 1 watt and have good power handling. Mine are bi-amped with 200 watts on the woofers and 100 watts up top.
IMHO They can't do live sound levels and I don't think I am selling them off short of their capabilities.
Rob🙂
I agree with you about an SPL contest. But this thread is about our experiences with home hifi, and I've pushed my home hifi to live/stadium levels and got better-than-live results.
But we haven't agreed on what is "high SPL"."
Hello Eric
To me high SPL is average levels into the upper 90's for a home setting. I usually listen in the mid to upper 80's range depending on the source material.
For a live setting 105-110 peaks are a good day. I have taken SPL meters into venues and had them peg at 116db and just stay there. That was a run for cover show. I always have ear plugs handy as you never know who's on the board, how much compression they will be using and if the guy running the board is hearing impaired or not.
I have never heard a single pair of commercially made speakers, short of horns, that could match some of the SPL levels I have been exposed too going to live events.
My larger speakers I was using as a comparison to the XPL clones are JBL 4344 clones. Those are 80's vintage monitors. The real deal, bandwidth limited 4 ways, compression driver mids and ring radiators up top. They are relatively efficient 93db 1 watt and have good power handling. Mine are bi-amped with 200 watts on the woofers and 100 watts up top.
IMHO They can't do live sound levels and I don't think I am selling them off short of their capabilities.
Rob🙂
sdclc126 said:
I was pulling your leg a little there. Of course a measurement graph is not an opinion. That goes without saying.
I think we need to raise the level a bit. Stating obvious things and acting a messenger for others opinions stating them as your own or as facts does not make a fruitful constructive discussion IMO.
There is no driver in Zaph's tests that outperform the C23 as you claimed. It has excellent measured performance. I know, I have measured them an other tweeters myself.
As for bang for the buck.. that is totally another story. And if you want a discussion on what tweeters give most value for money I guess we could start a thread about that.
Also as someone else mentioned, a couple of graphs doesn't tell the whole story. Many more measurements and of course listening tests needs to be done in order to evaluate a driver.
/Peter
Pan said:
Under the testing condition used by Zaph and concentrating on the area of distortion, yes there are better HF drivers and for less money.
"...Stating obvious things and acting a messenger for others opinions stating them as your own or as facts does not make a fruitful constructive discussion IMO."
I don't understand where this came from - agreeing with another person's methodology and using it to make my own build decisions is not acting as anyone's messenger or stating his opinions as my own.
"...a couple of graphs doesn't tell the whole story. Many more measurements and of course listening tests needs to be done in order to evaluate a driver."
Zaph, and others, have done many tests, both graphical and listening. I have neither the time nor the resources to do all that on my own - does each individual have to do this before building a speaker? If so, no one else's work has any meaning to anyone other than the person who did that work.
As for fruitful constructive discussion, I've simply stated my positions in response to what others, including you, have said here.
P.S. - ShinOBIWAN - thanks and yes I DO agree with your OPINION!!
Disclaimer: The opinions expressed here do not necessarily reflect those of the management, me, ShinOBIWAN, Zaph, or anyone else reading or contributing to this thread.
All characters depicted here are fictional and any resemblence to actual people is purely coincidental and unintentional.
You have the right to remain silent; anything you say here can and may be used against you...
😉
I don't understand where this came from - agreeing with another person's methodology and using it to make my own build decisions is not acting as anyone's messenger or stating his opinions as my own.
"...a couple of graphs doesn't tell the whole story. Many more measurements and of course listening tests needs to be done in order to evaluate a driver."
Zaph, and others, have done many tests, both graphical and listening. I have neither the time nor the resources to do all that on my own - does each individual have to do this before building a speaker? If so, no one else's work has any meaning to anyone other than the person who did that work.
As for fruitful constructive discussion, I've simply stated my positions in response to what others, including you, have said here.
P.S. - ShinOBIWAN - thanks and yes I DO agree with your OPINION!!
Disclaimer: The opinions expressed here do not necessarily reflect those of the management, me, ShinOBIWAN, Zaph, or anyone else reading or contributing to this thread.
All characters depicted here are fictional and any resemblence to actual people is purely coincidental and unintentional.
You have the right to remain silent; anything you say here can and may be used against you...
😉
Response
I wanted to respond to some acusations, but only so that others reading this will see the science through the smoke, since I think that the previous discussions did not do anything to clear up the arguments, they only made the situation more confusing.
Rather than respond to specific points, I will write a clear scientific question stating what was the point of discussion that I always assumed that I was responding to. The others will, of course, claim that these were not the points being discussed, but I would say to that that these were the arguments that I was responding to and and no other. If there is, as there usually is, a misunderstanding about the topic, then I claim no other position than the one stated here.
1) Could a single dome tweeter ever have the same maximum SPL capability or thermal capability as a compression driver on a waveguide?
- to me it is inconceivable that this could ever happen. A compression driver has a much larger diaphragm and voice coil than a dome/direct radiator tweeter. It also has an large efficiency gain through the waveguide. If the direct radiator is made larger to compete with the area and voice coil size of the compression driver then its directivity drops substantially. The compression driver's directivity does not depend on its size, it depends on the waveguide. Hence the compression driver can actually be made arbitrarily large for better and better heat dissipation (a kin to thermal compression) and SPL output. There are limits to this power expansion, of course, but the fact is that a dome tweeter does not have the design flexibility of the compression driver for achieving higher SPLs. This is why they are never used in high output pro applications.
Using multilple domes is no different than using multiple compression drivers so the argument has to be between a single unit of each.
Whether a direct radiator produces enough SPL for the application was never the argument. Thats a completely seperate topic in itself where one has to define "enough", for which there is no single deffinition and no single answer.
2) Does a dipole excite fewer modes than a monopole?
- the answer to this is clearly no. No one has ever shown mathematically that this was true, even though it has been claimed. The problem here is that a dipole excites a room in a different way than a monopole. The monopole excites the pressure and the dipole excites the velocity. Now the argument goes that a dipole does not excite a mode when it is on a node AND when it is not aligned with the mode velocity. But this ignores the fact that there are no velocity nodes in the same sense as there are pressure nodes. Pressure nodes are surfaces through the room, but velocity nodes are lines. Lines comprise a whole lot less space in the room than surfaces.
The situation is complex enough that a computer simulation is probably the best way to resolve the question. I did this back in the late 90's and it was published in JAES. In that paper I showed that a dipole does not produce any smoother response than a monopole, it only produces a lower response. This clearly implies that the claim for a dipole being "better" because it excites fewer modes is unfounded.
Linkwitz once complained to me that the simulation was only 2-D and that in 3-D it might come out differently. SO I did a full 3-D analysis and in that analysis the dipole actually faired worse. This later work was unpublished - I saw no reason since it did not change anything - so you will have to take my word for it.
To me, any arguments beyond this got lost in the noise and I claim no considered response to them. I will, however, stand by the claims above .
I wanted to respond to some acusations, but only so that others reading this will see the science through the smoke, since I think that the previous discussions did not do anything to clear up the arguments, they only made the situation more confusing.
Rather than respond to specific points, I will write a clear scientific question stating what was the point of discussion that I always assumed that I was responding to. The others will, of course, claim that these were not the points being discussed, but I would say to that that these were the arguments that I was responding to and and no other. If there is, as there usually is, a misunderstanding about the topic, then I claim no other position than the one stated here.
1) Could a single dome tweeter ever have the same maximum SPL capability or thermal capability as a compression driver on a waveguide?
- to me it is inconceivable that this could ever happen. A compression driver has a much larger diaphragm and voice coil than a dome/direct radiator tweeter. It also has an large efficiency gain through the waveguide. If the direct radiator is made larger to compete with the area and voice coil size of the compression driver then its directivity drops substantially. The compression driver's directivity does not depend on its size, it depends on the waveguide. Hence the compression driver can actually be made arbitrarily large for better and better heat dissipation (a kin to thermal compression) and SPL output. There are limits to this power expansion, of course, but the fact is that a dome tweeter does not have the design flexibility of the compression driver for achieving higher SPLs. This is why they are never used in high output pro applications.
Using multilple domes is no different than using multiple compression drivers so the argument has to be between a single unit of each.
Whether a direct radiator produces enough SPL for the application was never the argument. Thats a completely seperate topic in itself where one has to define "enough", for which there is no single deffinition and no single answer.
2) Does a dipole excite fewer modes than a monopole?
- the answer to this is clearly no. No one has ever shown mathematically that this was true, even though it has been claimed. The problem here is that a dipole excites a room in a different way than a monopole. The monopole excites the pressure and the dipole excites the velocity. Now the argument goes that a dipole does not excite a mode when it is on a node AND when it is not aligned with the mode velocity. But this ignores the fact that there are no velocity nodes in the same sense as there are pressure nodes. Pressure nodes are surfaces through the room, but velocity nodes are lines. Lines comprise a whole lot less space in the room than surfaces.
The situation is complex enough that a computer simulation is probably the best way to resolve the question. I did this back in the late 90's and it was published in JAES. In that paper I showed that a dipole does not produce any smoother response than a monopole, it only produces a lower response. This clearly implies that the claim for a dipole being "better" because it excites fewer modes is unfounded.
Linkwitz once complained to me that the simulation was only 2-D and that in 3-D it might come out differently. SO I did a full 3-D analysis and in that analysis the dipole actually faired worse. This later work was unpublished - I saw no reason since it did not change anything - so you will have to take my word for it.
To me, any arguments beyond this got lost in the noise and I claim no considered response to them. I will, however, stand by the claims above .
I for one have no problem with what's said above; I and others simply use different sets of priorities when approaching speaker design.
Maximum SPL and thermal capability for me do not (necessarily) equal high fidelity - my priority is distortion, regardless of SPL.
So I don't see real conflict here, just the age-old differences in goals and approach. The perennial multiple-ways-to-skin-a-cat thing.
Maximum SPL and thermal capability for me do not (necessarily) equal high fidelity - my priority is distortion, regardless of SPL.
So I don't see real conflict here, just the age-old differences in goals and approach. The perennial multiple-ways-to-skin-a-cat thing.
Re: Response
Earl: the Summas will blow-them-away at very high SPL, particularly the open baffle designs. These designs just don't have what it takes to take a lot of power and put out a lot of SPL.
You've provided no proof or evidence by way of measurement or argument. Time to let this claim go for what it is.
You are still sidestepping the main issue, which is that dipoles produce smoother bass response because of the way they excite the room modes. You stated this in the fifth sentence of the paragraph in post #215 where you attempted to debunk the dipole/mode myth.
The fact is that, in spite of (or because of) high air velocity at velocity nodes, there is no sound pressure at the velocity nodes. You stated that there are the same number of nodes excited by monopoles and dipoles, but the monopole's planar pressure nodes are exchanged for the dipole's linear velocity nodes. So if the dipole replaces pressure nodes that audibly color the bass for velocity nodes which produce no sound and so can't color the sound, the dipole produces less audible colorations from standing waves. This conclusion from your own analysis plus the inaudible nature of moving air seems obvious enough.
Metadiscussion: For his point 1), Earl changed the argument from his original assertion to a more restricted one, yet still provided no hard measurements. For point 2), Earl ignores the conclusions to be drawn from his modal analysis. He possibly dumbed down into strict falsehood some original "dipole claim", or dumbed it down into a strawman argument that he could knock down. Is the claim, as he wrote, "dipoles excite fewer modes" or is it more refined, like "dipoles excite fewer velocity modes" or "dipoles excite fewer bass-coloring, audible modes"?
- Eric
This is not the original issue: there wasn't even any mention of tweeters.... What you wrote in post #15 is:gedlee said:
Earl: the Summas will blow-them-away at very high SPL, particularly the open baffle designs. These designs just don't have what it takes to take a lot of power and put out a lot of SPL.
You've provided no proof or evidence by way of measurement or argument. Time to let this claim go for what it is.
gedlee said:
You are still sidestepping the main issue, which is that dipoles produce smoother bass response because of the way they excite the room modes. You stated this in the fifth sentence of the paragraph in post #215 where you attempted to debunk the dipole/mode myth.
The fact is that, in spite of (or because of) high air velocity at velocity nodes, there is no sound pressure at the velocity nodes. You stated that there are the same number of nodes excited by monopoles and dipoles, but the monopole's planar pressure nodes are exchanged for the dipole's linear velocity nodes. So if the dipole replaces pressure nodes that audibly color the bass for velocity nodes which produce no sound and so can't color the sound, the dipole produces less audible colorations from standing waves. This conclusion from your own analysis plus the inaudible nature of moving air seems obvious enough.
Metadiscussion: For his point 1), Earl changed the argument from his original assertion to a more restricted one, yet still provided no hard measurements. For point 2), Earl ignores the conclusions to be drawn from his modal analysis. He possibly dumbed down into strict falsehood some original "dipole claim", or dumbed it down into a strawman argument that he could knock down. Is the claim, as he wrote, "dipoles excite fewer modes" or is it more refined, like "dipoles excite fewer velocity modes" or "dipoles excite fewer bass-coloring, audible modes"?
- Eric
The biggest problem with Hi Fidelity is that people get to personal when others have opinions that differ from theirs. I certainly would be nice to avoid this.
Anyway, my priorities in defining better fidelity are:
1. Fast decay as possible as indicated in a CSD graph.
2. Detail resolution capability. (not really sure what data is associated with this yet).
3. Dynamics.
Lots of emphasis is put on THD these days, but I really can't find a close enough relationship with what is heard.
Anyway, my priorities in defining better fidelity are:
1. Fast decay as possible as indicated in a CSD graph.
2. Detail resolution capability. (not really sure what data is associated with this yet).
3. Dynamics.
Lots of emphasis is put on THD these days, but I really can't find a close enough relationship with what is heard.
sdclc126 said:
I never said that Maximum SPL and thermal capability are ALL thats required for high fidelity - its far more complex than that. What about directivity control - thats certainly more important than Max SPL. But you see, the dome looses out here too, it cannot have constant or controlled directivity - however that is an entirely different topic.
The reasons for choosing a compression driver and waveguide go far beyond simply max SPL.
I read what you said about distortion and I really do think that you need to read up on the work done in the area in the last five years. You are certainly free to discount it, but you should be aware of it. In my business virtually eveyone is coming around to the same point of view. A recent addition to the list is Lauri Fincham (KEF, JBL, THX) who gave a talk in LV in January and stated that in his opinion THD and IMD were virtually irrelavent. Nobody who has looked into the situation continues to believe that these measures of sound quality tell us anything.
I think this is quite interesting, because I never thought of any data that tells us the whole picture about sound quality, but rather think that data is used to help pinpoint specific areas that can be improved.gedlee said:
Re: Re: Response
You are so obnoxious that I am tempted not to even bother to respond, but you are also so incorrect that I feel that I must.
First, monopoles in real rooms do produce as smooth or smoother response than dipoles. Proof - read my AES paper.
Second a velocity node is a pressure maximum - your claim that there is "no sound pressure at the velocity nodes" is completely wrong. I don't need to prove this its simply common physics.
Third "high air velocity at velocity nodes" - if its a node then the velocity is zero.
How do you expect me to carry on a simple discussion with you when you mistate the basic physics so badly.
go back and read what you said previously
"This argument is kind of like saying that a room full of equalized sealed monopole (sub)woofers with smooth and flat in-room response is incorrect. Why is it incorrect? Because the response inside the cabinets is not flat."
I am saying that "a room full of equalized sealed monopole (sub)woofers with smooth and flat in-room response is" CORRECT! I have no idea what you are trying to say, but it sounds like you agree with me.
Half the time I can't even figure out what you are saying, the other half, well ...
Eric Weitzman said:
You are so obnoxious that I am tempted not to even bother to respond, but you are also so incorrect that I feel that I must.
First, monopoles in real rooms do produce as smooth or smoother response than dipoles. Proof - read my AES paper.
Second a velocity node is a pressure maximum - your claim that there is "no sound pressure at the velocity nodes" is completely wrong. I don't need to prove this its simply common physics.
Third "high air velocity at velocity nodes" - if its a node then the velocity is zero.
How do you expect me to carry on a simple discussion with you when you mistate the basic physics so badly.
go back and read what you said previously
"This argument is kind of like saying that a room full of equalized sealed monopole (sub)woofers with smooth and flat in-room response is incorrect. Why is it incorrect? Because the response inside the cabinets is not flat."
I am saying that "a room full of equalized sealed monopole (sub)woofers with smooth and flat in-room response is" CORRECT! I have no idea what you are trying to say, but it sounds like you agree with me.
Half the time I can't even figure out what you are saying, the other half, well ...
"I read what you said about distortion and I really do think that you need to read up on the work done in the area in the last five years."
Sure I'm very interested (honestly) - please post links/sources etc.
"I never said that Maximum SPL and thermal capability are ALL thats required for high fidelity...."
Well, I didn't mean to imply that you had, but it seems to be the focus of much of what you've said here.
soongsc - post #276 -
2. Detail resolution capability. (not really sure what data is associated with this yet).
That would be distortion (if not in whole, in part).
Sure I'm very interested (honestly) - please post links/sources etc.
"I never said that Maximum SPL and thermal capability are ALL thats required for high fidelity...."
Well, I didn't mean to imply that you had, but it seems to be the focus of much of what you've said here.
soongsc - post #276 -
2. Detail resolution capability. (not really sure what data is associated with this yet).
That would be distortion (if not in whole, in part).
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