I know that I am going against the grain for this forum, but I personaly think that we should not fault a disign for having little or no BSC. I have been playing the level of BSC in my design (which uses the 9930 that PE has on sale) and I am not convinced one way or the other about its necessity. I started looking at BSC more criticaly after seeing a pair of Linn speakers taken apart with crossover exposed... no BSC at all! And these are speakers I respect very much (my refrence speakers are Katans). I realize that they are a speaker that are not for everybody (probably because of the lack of BSC) but they also have virtues that I do not hear very often in comperably priced speakers (also probably due to the lack of BSC).
I dont mean to start a BSC war here, I just wanted to point out that Dr. D'Appolito is fully aware of the issue and chose to handle it the way that he did. Also, I would not be suprized if the 1.8mH did provide a dB or 2 of BSC and the quoted SPL is just optimistic. Or perhapse the driver is more sensitive than we think, the manufacturer quotes it at 87dB, and Zaph's SPL is calculated with his TS params, not measured.
Anyways, I think this kit looks like a real winner, even if we are just looking at what you get for the price!
-Chad
I dont mean to start a BSC war here, I just wanted to point out that Dr. D'Appolito is fully aware of the issue and chose to handle it the way that he did. Also, I would not be suprized if the 1.8mH did provide a dB or 2 of BSC and the quoted SPL is just optimistic. Or perhapse the driver is more sensitive than we think, the manufacturer quotes it at 87dB, and Zaph's SPL is calculated with his TS params, not measured.
Anyways, I think this kit looks like a real winner, even if we are just looking at what you get for the price!
-Chad
Hi,
All I'm saying is things like this should be spelt out in the design.
PEs frequency response graphs IMO leave a lot to be desired.
I'm also saying it won't sound anything like Zaphs designs.
The limited attenuation of the tweeter also indicates no BSC.
I really do not like misleading frequency response graphs.
/sreten.
All I'm saying is things like this should be spelt out in the design.
PEs frequency response graphs IMO leave a lot to be desired.
I'm also saying it won't sound anything like Zaphs designs.
The limited attenuation of the tweeter also indicates no BSC.
I really do not like misleading frequency response graphs.
An externally hosted image should be here but it was not working when we last tested it.
/sreten.sreten said:
For sure! I cant decide how much BSC I like in my design (I am not even concidering full correction, but I think there is something strangely compelling about none) but I would never imply that it isnt a major design decision and drasticaly changes the sound of the speaker system. This design obviously has either very little or no BSC and would sound very different from Zaph's. I was actually suprized when I switched my tweeter from the H1212 to the 9930 by how much less efficient the Usher is. So, it doens't have very much padding, but it doesn't have much efficency either.
I also totaly agree about PEs design documentation. I would guess that this is just like a Stereophile FR graph where the near-field is merged to the far without any baffle effects added in. Even if this design did have a dB or 2 of BSC the graph still wouldn't look anything like that in free-space. They are obviously trying to sell their kits, but they are selling them to a different crowd than Wilson Audio is!
I really wish I had the $ to build this kit as-is and Zaph's L18 design. It would be like polar oposites I expect. And I am sure there are those that would prefer one and those that would like the other. I am pretty sure which I would like better
.-Chad
Wooooo BSC war!
Most of my designs have near-full BSC. It's a design decision based on the fact that I don't design for compromised speaker setup. In other words, I don't design for tiny rooms, placement up against a wall, or in a bookshelf.
With Joe's 1.8mH inductor, there is some BSC there, but not as much as I might do. This isn't a design flaw, it's just choice. Joe is wise in attempting to cover a few more placement possibilities than I might. As a result, in some larger rooms, his Usher system might sound a small bit leaner in the low end. Rest assured that it probably still sounds great however because the Ushers are great drivers and Joe is a good designer.
BTW, beware of the "calculated" SPL on my T/S parameter sheets. They are only calculated, and as such they are not accurate. The more accurate level is on the frequency response curve.
Most of my designs have near-full BSC. It's a design decision based on the fact that I don't design for compromised speaker setup. In other words, I don't design for tiny rooms, placement up against a wall, or in a bookshelf.
With Joe's 1.8mH inductor, there is some BSC there, but not as much as I might do. This isn't a design flaw, it's just choice. Joe is wise in attempting to cover a few more placement possibilities than I might. As a result, in some larger rooms, his Usher system might sound a small bit leaner in the low end. Rest assured that it probably still sounds great however because the Ushers are great drivers and Joe is a good designer.
BTW, beware of the "calculated" SPL on my T/S parameter sheets. They are only calculated, and as such they are not accurate. The more accurate level is on the frequency response curve.
Zaph, you get discussed a lot on these boards but I never actually think about you sitting and reading what we are saying about you and your work (note to self: try not to bad-mouth Zaph as much ).
Have you ever tested the 9930? What do you think of the other design choices Joe made with this design? Is the 9930 totaly up to the 2000 crossover? Because it looks the 8945A could go a little higher without the major dip/peak getting too close to the crossover point. It just seems like the 9930 would be hard pressed to have lower distortion or sound less strained than the woofer with that crossover point, and the woofers breakup seems rather benign in terms of distortion. What are other peoples feelings on the 2k crossover?
Oh... and just to play devils-advocate Linn would say that close wall placement is not a "compromise". All rooms have walls regardless of size, not everybody has enough room to place their speakers 2-3ft from the walls.
-Chad
).Have you ever tested the 9930? What do you think of the other design choices Joe made with this design? Is the 9930 totaly up to the 2000 crossover? Because it looks the 8945A could go a little higher without the major dip/peak getting too close to the crossover point. It just seems like the 9930 would be hard pressed to have lower distortion or sound less strained than the woofer with that crossover point, and the woofers breakup seems rather benign in terms of distortion. What are other peoples feelings on the 2k crossover?
Oh... and just to play devils-advocate Linn would say that close wall placement is not a "compromise". All rooms have walls regardless of size, not everybody has enough room to place their speakers 2-3ft from the walls.
-Chad
Zaph said:Wooooo BSC war!
Most of my designs have near-full BSC. It's a design decision based on the fact that I don't design for compromised speaker setup. In other words, I don't design for tiny rooms, placement up against a wall, or in a bookshelf.
Zaph,
I'd be interested in what you consider near-full BSC. Some of the locals here in the Northwest have had discussions on that very topic. I realize that there is a difference between designing for a particular application or a specific room and a more generic approach that should work in "most" situations.
I tend to believe that 3dB works in my somewhat small room, Dan Wiggins' designs tend toward a more generic 4dB, with cabin or room gain doing the rest. Others have opted for a full 6dB.
What say you?
Best Regards,
TerryO
TerryO said:
Near full BSC could be anything from 4 to 6 dB.
A lot of factors contribute to what I select for BSC, including low end response shaping based on the selected tuning, midbass and bass distortion levels, and more, on top of the normal room size and speaker placement options.
This may seem out of character coming from "Mr. Objectivity" but in addition to the considerations listed above, I often let my ears decide what amount of BSC sounds best for a given design. The right amount can be hard to model or predict due to so many variables, so a good listening test helps. I've never done any less than 4dB for a speaker that wasn't designed to be placed against the wall or used very nearfield.
ch83575 said:
I've never tested any Usher tweeters, but I hope to change that someday. (unless we count the Dayton RS28, which is an Usher product)
I do call close wall placement a compromise, at least when done with normal rectangular shaped boxes. It moves the first rear wall reflection higher in frequency where it's more audible, and the response curve aberrations caused by the early reflection have less "room diffusion" to smooth out the percieved sound. Bottom line, up against a wall sounds worse than a few feet out. I don't know, I suppose it could just be called a placement limitation rather than a compromise.
In-wall speakers have the potential to be less of a compromise than a box speaker placed close to the wall, though of course they have their own set of compromises.
Another reason the baffle step issue is problematic is that the on axis spl drop/rise is 6 dB, but the power response drop/rise is only 3 dB
See JohnK's discussion here
http://www.musicanddesign.com/PowerMatching.html
Depending how far away you listen to your speakers, and what the room is like, and what your speaker is in relation to the boundry...
So there is no clear cut answer. I think you have to target between 3-6dB. Closer to 6 if your speakers are out from the walls and you're "close" to the speakers. Closer to 3dB if you're well beyond the critical distance and or the speakers are close to the bounary/walls.
See JohnK's discussion here
http://www.musicanddesign.com/PowerMatching.html
Depending how far away you listen to your speakers, and what the room is like, and what your speaker is in relation to the boundry...
So there is no clear cut answer. I think you have to target between 3-6dB. Closer to 6 if your speakers are out from the walls and you're "close" to the speakers. Closer to 3dB if you're well beyond the critical distance and or the speakers are close to the bounary/walls.
Zaph said:
I guess you are right. If you choose to make a speaker sound ITS best in any room as opposed to sounding the best it possibly can, but only in some rooms that can acomodate the proper setup... well that is the definition of a compermise isn't it. It seems to me more and more that this hoby is nothing but one compermise after another and balancing what you will and will not compermise with is the real art of speaker designing
.I also feel that the choice of BSC can greatly effect the pace and timing of the speaker. I know there are those (Zaph included) that dont put much value in such things, but there are a lot of people (more in England than US) that think of it as one of the most important factors in music reproduction. I feel from my own listening experiments that the more BSC you introduce the less the transients line up with the bass. This causes the speaker to have what I can only describe as poor timing. Linn has no BSC and the best timing I have heard, but I am not absolutly enthraled with their voicing and sonic realism with orchestral music. I don't have anything but my ears to back this up with though, so I dont expect to be given much heed. Perhapse there is some other brave soul out there who can help me find a reason for what I am hearing that could be tested and illustrated with a chart or graph.
-Chad
sreten said:
Hi,
I'm sorry but this is simply not true. I'm a bass player, I ought to know.
I realize my post is less than objective, but at least i try to explain my position... your post does not help me further my knoledge of the effects of BSC at all. I doubt I am the only person who feels that way.
I have heard many bass players who have no timing in their playing, so playing bass in no way makes me think you must be super sensitive to timing issues in reproduced music.
Let me re-phrase my original comment to try to get a more involved answer: My Linn speakers have very excellent timing. I am not the only person out there that feels that most commercial speakers fall very flat in this department. I dont think it is wrong to evaluate a speaker based on how it "sounds" so I think it is unfair to tell me I am wrong to evaluate a speaker based on its precived timing. Everybody has their own listening criteria, and mine happen to put timing and pace close to the top of the list. I realize that timing does not come into play in some peoples criteria at all, but I think it would be nieve to say that it does not exist as an aspect that diferentiates one speaker from another. If you dont notice timing issues in any of your speakers try living with a pair of Linns for a while... if you still dont notice any difference, fine... no skin of my back, just dont tell me that I can not hear the difference!
Ok... back to the Linns. They have good timing. They are my reference at the momment and I have been measureing them extensivly and examining their crossovers and found that they have no BSC that is noticable. I am (through listening test with my own project) begining to think this is what is responsible for their excellent timing. If you think there is no correlation between BSC and precived timing then what else might I investigate to find the source of this aspect of the Linn speakers that I would like to replicate? Or am I just stupid and hearing thinks that dont exist
?Thanks for your help and informed comments,
-Chad
ch83575 said:
I realize my post is less than objective, but at least i try to explain my position... your post does not help me further my knoledge of the effects of BSC at all. I doubt I am the only person who feels that way.
I have heard many bass players who have no timing in their playing, so playing bass in no way makes me think you must be super sensitive to timing issues in reproduced music.
Let me re-phrase my original comment to try to get a more involved answer: My Linn speakers have very excellent timing. I am not the only person out there that feels that most commercial speakers fall very flat in this department. I dont think it is wrong to evaluate a speaker based on how it "sounds" so I think it is unfair to tell me I am wrong to evaluate a speaker based on its precived timing. Everybody has their own listening criteria, and mine happen to put timing and pace close to the top of the list. I realize that timing does not come into play in some peoples criteria at all, but I think it would be nieve to say that it does not exist as an aspect that diferentiates one speaker from another. If you dont notice timing issues in any of your speakers try living with a pair of Linns for a while... if you still dont notice any difference, fine... no skin of my back, just dont tell me that I can not hear the difference!
Ok... back to the Linns. They have good timing. They are my reference at the momment and I have been measureing them extensivly and examining their crossovers and found that they have no BSC that is noticable. I am (through listening test with my own project) begining to think this is what is responsible for their excellent timing. If you think there is no correlation between BSC and precived timing then what else might I investigate to find the source of this aspect of the Linn speakers that I would like to replicate? Or am I just stupid and hearing thinks that dont exist
Thanks for your help and informed comments,
-Chad
Sorry, what's "timing"?
Sorry, I posted this in the previous post before I noticed they were split... thanks Cal.
Post #12
Timing in a sound reproduction system is the sense that all of the parts of the music line up in time. I realize this is hard to invision when we are used to looking at graphs in the time domain like group delay, and cant see any major issues, but it is easy enough to hear. Some speakers tend to smear timing cues, somtimes it is as bad as sounding like the bass player was in a different room as the drummer (and the drummer was probably durnk) other times very short transient sounds like the innitial attack of a snare do not seem to be made at the exact same time as the resonance of the same drum stroke. This in the larger scale leads to speakers that have no drive or pacing and are not very engaging. It is more objectional in Jazz Blues and rock than in classical, but it is still noticable in the smoothness of the musical flow even there. By now I am sure that people think I read too many audiophile rags and the stoning will begin soon, but I like to think that I come to these conclusions by listening to music instead of listening to speakers.
I also think that some people lack the ability (literaly) to properly evaluate the timing in speakers because their source and amplifier muck it up so much even the best speakers in this regard would sound poor with their equipment. Remember... source first!
-Chad
Post #12
Timing in a sound reproduction system is the sense that all of the parts of the music line up in time. I realize this is hard to invision when we are used to looking at graphs in the time domain like group delay, and cant see any major issues, but it is easy enough to hear. Some speakers tend to smear timing cues, somtimes it is as bad as sounding like the bass player was in a different room as the drummer (and the drummer was probably durnk) other times very short transient sounds like the innitial attack of a snare do not seem to be made at the exact same time as the resonance of the same drum stroke. This in the larger scale leads to speakers that have no drive or pacing and are not very engaging. It is more objectional in Jazz Blues and rock than in classical, but it is still noticable in the smoothness of the musical flow even there. By now I am sure that people think I read too many audiophile rags and the stoning will begin soon, but I like to think that I come to these conclusions by listening to music instead of listening to speakers.
I also think that some people lack the ability (literaly) to properly evaluate the timing in speakers because their source and amplifier muck it up so much even the best speakers in this regard would sound poor with their equipment. Remember... source first!
-Chad
ch83575 said:
Hi,
a) I could say exactly the same thing to you.
b) I would not have mentioned it if I couldn't play the thing, you
don't know, you get told you have good timing when you learn it.
I've been playing long enough now to know now I've got it.
Consider a scientific experiment :
the use of line level BSC instead of passive in the loudspeaker.
Would you hear the same things as you reduced the BSC ?
/Sreten.I like your experiment... but it doesn't sound very easy. It would probably clerify if timing mistakes are originating in loudspeaker or amp, or just inherent in BSC in general. But it seems that I would need passive crossovers with 3 or 4 different levels of BSC and an active filter with matching BSC shelving circuits. Then, for each switch in BSC the speakers should be re-positioned if I am going to be totaly accurate about how it effects the final product. Perhapse I will give it a try, but it sounds like a lot of $ worth of inductors . To be honest I am not doing my listening tests with a passive crossover but with SoundEasy's crossover emulator.
So I have one more thought to bring up with you all. Does anybody else notice a difference when implementing BSC with an oversized series inductor on the woofer as opposed to the parallel inductor/resistor shelving filter that is used in some designs? I find that they sound different even when adjusted so that the overall FR is very close through the baffle step region. Again this is with SoundEasy... perhapse that is a fault in my testing procedure?
sreten: I didn't mean to insult your bass playing. I just dont feel that I can assume that your sense of timing is impecable because of it, nor can I assume it isn't... I can assume that you make no assumptions about my timing one way or another. Wait... I am confused .
Thanks,
-Chad
. To be honest I am not doing my listening tests with a passive crossover but with SoundEasy's crossover emulator.So I have one more thought to bring up with you all. Does anybody else notice a difference when implementing BSC with an oversized series inductor on the woofer as opposed to the parallel inductor/resistor shelving filter that is used in some designs? I find that they sound different even when adjusted so that the overall FR is very close through the baffle step region. Again this is with SoundEasy... perhapse that is a fault in my testing procedure?
sreten: I didn't mean to insult your bass playing. I just dont feel that I can assume that your sense of timing is impecable because of it, nor can I assume it isn't... I can assume that you make no assumptions about my timing one way or another. Wait... I am confused
.Thanks,
-Chad
sreten: I didn't mean to insult your bass playing. I just dont feel that I can assume that your sense of timing is impecable because of it, nor can I assume it isn't... I can assume that you make no assumptions about my timing one way or another. Wait... I am confused
Thanks,
-Chad [/B]
Hi,
I was being somewhat facetious.
Musical timing (and lack of it) is an accepted phenomena.
Timing mistakes in hi-fi equipment - different ball game.
/sreten.Yea... that assumption part was suposed to be kinda a joke (except for the part where I said I didn't want to insult your playing... I dont).
So, you seriously think that timing errors in hi-fi playback are a myth? And companies like Linn and Naim that basicaly started what we know of as hi-end playback are just built on lies? Is this a general consensus around here? If so I find this a jagged pill to swallow.
-Chad
So, you seriously think that timing errors in hi-fi playback are a myth? And companies like Linn and Naim that basicaly started what we know of as hi-end playback are just built on lies? Is this a general consensus around here? If so I find this a jagged pill to swallow.
-Chad
Hi,
What can be suggested to be a timing issue, i.e. it sounds like it has
more timing, doesn't mean it has more timing. Naim amplifiers sound like they have really good "grip" of the speakers but they don't "grip"
a speaker better than other amplifiers - they are built with internal
details that cause this apparent phenomena / type of sound.
/sreten.
What can be suggested to be a timing issue, i.e. it sounds like it has
more timing, doesn't mean it has more timing. Naim amplifiers sound like they have really good "grip" of the speakers but they don't "grip"
a speaker better than other amplifiers - they are built with internal
details that cause this apparent phenomena / type of sound.
/sreten.- Status
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