I have met plenty of audio engineers (recording) who like, and even envy, tube preamps, MacIntosh amplifiers and maybe $30K speakers.
One big difference tho, as you point out, is room treatment. The pros tend to invest heavily in it, the home audio fan hardly at all. Too bad....
One big difference tho, as you point out, is room treatment. The pros tend to invest heavily in it, the home audio fan hardly at all. Too bad....
Going back to the original post
Getting back to the original premise of this thread. Why three speakers with theoretical "equally flat" frequency domain measurements would, or should I say WILL exhibit different sound qualities?
There are of course additional, valid measurement criteria commonly used for "technical" speaker evaluation. Several of those criteria have been discussed in this thread. They all, one way or another contribute to the understanding of how a particular speaker performs.
However, after building speakers of various designs, capabilities and sizes for a lot of years, there are a few personal observations I would like to share. These comments are more in the area of subjective design observations - decisions and less about measurement. Some will agree, some will not. And, all of this has been said before one time or one way or another. Just want to stimulate the discussion.
1) Once one achieves a flat frequency response. some additional positive performance byproducts usually follow, such as a good power response. Not always the case, but usually is. I use a flat frequency response goal as a starting point. Eliminating or controlling peaks and dips, basically integrating each driver with it self and or with the other driver(s) in the system.
2) Tonal qualities of the drive units themselves. Paper sounds like, well, PAPER. Paper drivers will vary as will other materials, too numerous to mention here. The successful mating of driver sonic signatures can make or break a system. Each driver has its own personality, distortion profile. One needs to learn and understand how to best implement a given driver. Driver selection and crossover topologies play an important role here.
3) Polar response. This is area in which trade offs (mostly crossover) are made to produce a particular, and hopefully positive outcome. It seems that speakers with a well engineered polar response tend to be the most forgiving. Forgiving of various room issues and placement issues. The speaker feels more coherent. It seems to disappear in it's playback environment. Performs closer to an ideal point source.
4) Dynamics. IMHO, this is a very UNDERRATED aspect of speaker design. It is ALWAYS a trade off. Big dynamics take big drivers and it is much easier to do with high quality, light cone high efficiency drivers. You can listen to the best of the smaller, high quality systems, that for their size are about as dynamic as the current technology can provide. But when you compare them to, say an Altec (or other similar driver) 604 duplex, the difference in dynamics is startling!! You quickly see, or should I say hear and feel how much dynamic compression the smaller system has. Just the way it is! However, the closer to reality dynamics of the large 16" mid bass - mid range duplex comes at a cost, that is a paper tonal quality, a less resolved upper mid range and a HUGE enclosure. I just takes a lot of area to produce dynamics. Again, just the way it is. By and large, the speakers with the largest possible mid range driver tend to sound more realistic at live playback levels. This assumes a flat frequency response, modern low distortion drivers and an excellent crossover topology. Poor crossovers are big dynamics robbers.
5) Set up and associated equipment matching. One could write a book on this topic. One thing that continues to amaze me is how poorly so many systems are set up. From residential to CES, The Show, RMAF and on and on. This is a bit of art and common sense. One common factor is that SO MANY equipment users trying to get the system to do what it is not capable of doing! Or using set up to correct for a particular speaker flaw and they end up defeating the remaining good qualities of the speaker. Or of the room.
OK, Ramble over. Interested in what others have to say.
Getting back to the original premise of this thread. Why three speakers with theoretical "equally flat" frequency domain measurements would, or should I say WILL exhibit different sound qualities?
There are of course additional, valid measurement criteria commonly used for "technical" speaker evaluation. Several of those criteria have been discussed in this thread. They all, one way or another contribute to the understanding of how a particular speaker performs.
However, after building speakers of various designs, capabilities and sizes for a lot of years, there are a few personal observations I would like to share. These comments are more in the area of subjective design observations - decisions and less about measurement. Some will agree, some will not. And, all of this has been said before one time or one way or another. Just want to stimulate the discussion.
1) Once one achieves a flat frequency response. some additional positive performance byproducts usually follow, such as a good power response. Not always the case, but usually is. I use a flat frequency response goal as a starting point. Eliminating or controlling peaks and dips, basically integrating each driver with it self and or with the other driver(s) in the system.
2) Tonal qualities of the drive units themselves. Paper sounds like, well, PAPER. Paper drivers will vary as will other materials, too numerous to mention here. The successful mating of driver sonic signatures can make or break a system. Each driver has its own personality, distortion profile. One needs to learn and understand how to best implement a given driver. Driver selection and crossover topologies play an important role here.
3) Polar response. This is area in which trade offs (mostly crossover) are made to produce a particular, and hopefully positive outcome. It seems that speakers with a well engineered polar response tend to be the most forgiving. Forgiving of various room issues and placement issues. The speaker feels more coherent. It seems to disappear in it's playback environment. Performs closer to an ideal point source.
4) Dynamics. IMHO, this is a very UNDERRATED aspect of speaker design. It is ALWAYS a trade off. Big dynamics take big drivers and it is much easier to do with high quality, light cone high efficiency drivers. You can listen to the best of the smaller, high quality systems, that for their size are about as dynamic as the current technology can provide. But when you compare them to, say an Altec (or other similar driver) 604 duplex, the difference in dynamics is startling!! You quickly see, or should I say hear and feel how much dynamic compression the smaller system has. Just the way it is! However, the closer to reality dynamics of the large 16" mid bass - mid range duplex comes at a cost, that is a paper tonal quality, a less resolved upper mid range and a HUGE enclosure. I just takes a lot of area to produce dynamics. Again, just the way it is. By and large, the speakers with the largest possible mid range driver tend to sound more realistic at live playback levels. This assumes a flat frequency response, modern low distortion drivers and an excellent crossover topology. Poor crossovers are big dynamics robbers.
5) Set up and associated equipment matching. One could write a book on this topic. One thing that continues to amaze me is how poorly so many systems are set up. From residential to CES, The Show, RMAF and on and on. This is a bit of art and common sense. One common factor is that SO MANY equipment users trying to get the system to do what it is not capable of doing! Or using set up to correct for a particular speaker flaw and they end up defeating the remaining good qualities of the speaker. Or of the room.
OK, Ramble over. Interested in what others have to say.
Don't know about "PWK" but here's Linkwitz: "I confirmed that an overall flat on-axis frequency response is not optimum in a reverberant room and that there has to be some kind of response shaping for frequencies above 1 kHz. We found that a small amount of high frequency roll-off was necessary and that particularly the center frequency of the shelving filter was extremely critical."
Polar response
Most sound horrible and have no accuracy, aside, they do not use the big monitors for mixing most if not all mixing are done via the nearfields and the final mix and changes are done by the mastering engineer before going to press.
Simply put - you wouldn't with and you wouldn't without...
Slightly off topic as not exactly what you are looking for (more questioning than answers), but maybe interesting for you as well :
Audio and Loudspeaker Design Guide Lines
Michael
John,
I'm glad to hear your opinion. I know you've done lots of different designs and your input is obviously valuable.
Which cone material, in your opinion gives the best trade-offs between tone, distortion, and resonances?
What speaker system or design gives the best trade-off between dynamics and size?
I'm glad to hear your opinion. I know you've done lots of different designs and your input is obviously valuable.
Which cone material, in your opinion gives the best trade-offs between tone, distortion, and resonances?
What speaker system or design gives the best trade-off between dynamics and size?
Great post John.
Ra7, check this out for cone tech: http://www.infinitysystems.com/home/technology/whitepapers/cmmd.pdf
Here's a couple other quick papers and demos on the topic. Interesting stuff.
http://www.audioxpress.com/magsdirx/voxcoil/addenda/media/klasco409.pdf
The Art of Speaker Design, Part II
http://www.audioxpress.com/magsdirx/voxcoil/addenda/media/klasco409.pdf
http://www.loudsoft.com/\loudsoft\my files\ALMA Paper 2003.pdf
Benefits of Acoustic FE/BE Analysis
http://www.klippel.de/pubs/Klippel papers/Measurement_and_Visualization_Cone_vibration_06.pdf
There's some about it on my blog as well and this thread as well: http://www.hawthorneaudio.com/forums/viewtopic.php?f=2&t=3581
Dan
Ra7, check this out for cone tech: http://www.infinitysystems.com/home/technology/whitepapers/cmmd.pdf
Here's a couple other quick papers and demos on the topic. Interesting stuff.
http://www.audioxpress.com/magsdirx/voxcoil/addenda/media/klasco409.pdf
The Art of Speaker Design, Part II
http://www.audioxpress.com/magsdirx/voxcoil/addenda/media/klasco409.pdf
http://www.loudsoft.com/\loudsoft\my files\ALMA Paper 2003.pdf
Benefits of Acoustic FE/BE Analysis
http://www.klippel.de/pubs/Klippel papers/Measurement_and_Visualization_Cone_vibration_06.pdf
There's some about it on my blog as well and this thread as well: http://www.hawthorneaudio.com/forums/viewtopic.php?f=2&t=3581
Dan
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RA7
Thank you for your positive comment. Now getting down to cases. I was afraid someone would ask your question. And of course there is no one simple answer. So what follows is opinion, little more.
One can narrow down potential cone materials & drivers but only after one makes more than a few key decisions. Making honest common sense decisions relative to YOUR priorities is key to YOUR speakers performance. The usual stuff. How loud, what size room, budget, physical size limitations, woofer loading - alignment, low end cut off, acceptable cosmetics and so on. A speaker system is, well, a system. So a long term system design approach is appropriate. And each decision - consideration one makes effects all the others you will make. It can be maddening! Practical performance goals are mandatory for success. However, defining "practical" can be a real stinker!
If killer dynamics is your dominate goal, on the bottom end through the mid range, light weight paper cones are still hard to beat. Some would prefer reflex loading, some horn. The reflex can play up higher as it has a direct radiation into the room where most horns that can play down deep are buried. Yes, there are front radiating bass horns, but internal reflections are tough to deal with so they tend to be lumpy above a couple of hundred cycles.
One can go on and on about which design has what virtues. The above doesn't even begin to scratch the surface for a woofer.
Now that I have done my best to dodge your two questions, I feel well designed, large format paper below 500 HZ is still hard to beat. If you are out by 500 Hz or so, most of the paper sound is gone, well, limited. Good metal woofer diaphragms can out resolve paper and sound a bit more neutral, but they tend to be less dynamic and require heroic crossover work and or steep active filtration. Steep filtration makes it difficult to "blend" with the driver above it and so it goes.
One of the contributors over at the Altec site I think has a tag line "a 6-1/2 inch is not a woofer". If you want life like dynamics, the 6-1/2 isn't even a mid range! Looking to pro audio, you see a LOT of dedicated 8-15" mid range units. For home audio, 8" is a good compromise. And again, these larger dedicated mid ranges tend to be paper of one sort or another. The good news is, by and large, as the paper cone gets smaller, it's paper sound gets smaller too. This is a VERY general observation and assumes one is talking about the better high end drivers. Stuff like slit cone designs with advanced motors and suspensions.
As for a complete system size, a direct radiating 12-18" woofer, 8-10" mid and from 1,500 or so up a horn. Still going to be a BIG speaker, but no where near what an all horn system with equal low end cut off would be. As I write that last sentence I know it will set a lot of folks spinning! There are so many ways around the barn. It all gets back to a fundamentally sound design (no pun on the sound) being well executed. You gotta know what you want and do the work and spend the money.
One last thing, there are so many exotic cone and diaphragm materials available today. Seems to be the signature item in most high end speaker designs. Funny thing though, very few if any of them seem to dominate, or set a new material standard. Good old paper can and does compete with the best of them and for a WAY lower cost. I know there will be others that disagree, but when I look to the last 100 years of history, that is what I see.
Thank you for your positive comment. Now getting down to cases. I was afraid someone would ask your question. And of course there is no one simple answer. So what follows is opinion, little more.
One can narrow down potential cone materials & drivers but only after one makes more than a few key decisions. Making honest common sense decisions relative to YOUR priorities is key to YOUR speakers performance. The usual stuff. How loud, what size room, budget, physical size limitations, woofer loading - alignment, low end cut off, acceptable cosmetics and so on. A speaker system is, well, a system. So a long term system design approach is appropriate. And each decision - consideration one makes effects all the others you will make. It can be maddening! Practical performance goals are mandatory for success. However, defining "practical" can be a real stinker!
If killer dynamics is your dominate goal, on the bottom end through the mid range, light weight paper cones are still hard to beat. Some would prefer reflex loading, some horn. The reflex can play up higher as it has a direct radiation into the room where most horns that can play down deep are buried. Yes, there are front radiating bass horns, but internal reflections are tough to deal with so they tend to be lumpy above a couple of hundred cycles.
One can go on and on about which design has what virtues. The above doesn't even begin to scratch the surface for a woofer.
Now that I have done my best to dodge your two questions, I feel well designed, large format paper below 500 HZ is still hard to beat. If you are out by 500 Hz or so, most of the paper sound is gone, well, limited. Good metal woofer diaphragms can out resolve paper and sound a bit more neutral, but they tend to be less dynamic and require heroic crossover work and or steep active filtration. Steep filtration makes it difficult to "blend" with the driver above it and so it goes.
One of the contributors over at the Altec site I think has a tag line "a 6-1/2 inch is not a woofer". If you want life like dynamics, the 6-1/2 isn't even a mid range! Looking to pro audio, you see a LOT of dedicated 8-15" mid range units. For home audio, 8" is a good compromise. And again, these larger dedicated mid ranges tend to be paper of one sort or another. The good news is, by and large, as the paper cone gets smaller, it's paper sound gets smaller too. This is a VERY general observation and assumes one is talking about the better high end drivers. Stuff like slit cone designs with advanced motors and suspensions.
As for a complete system size, a direct radiating 12-18" woofer, 8-10" mid and from 1,500 or so up a horn. Still going to be a BIG speaker, but no where near what an all horn system with equal low end cut off would be. As I write that last sentence I know it will set a lot of folks spinning! There are so many ways around the barn. It all gets back to a fundamentally sound design (no pun on the sound) being well executed. You gotta know what you want and do the work and spend the money.
One last thing, there are so many exotic cone and diaphragm materials available today. Seems to be the signature item in most high end speaker designs. Funny thing though, very few if any of them seem to dominate, or set a new material standard. Good old paper can and does compete with the best of them and for a WAY lower cost. I know there will be others that disagree, but when I look to the last 100 years of history, that is what I see.
OK, somebody has to say it clearly:
1. all over this thread there are people swearing flat frequency response is crucial.
2. some posters in this thread and often a universally agreed conclusion in other threads is that flat response never sounds right at home.
Let's have a show of hands. Can't be both ways.
Footnote: a smooth frequency response (but not necessarily flat) is something different and I am sure few would doubt its importance.
Footnote: can't say as I've ever heard studio sound that I'd like to have playing a Mahler symphony or anything else at home. Contrary to naive first impressions, I don't think there really is a compelling reason why the recording engineer and producer need home-hifi sound in the studio in order to create recordings that sound great on home hifis. Maybe an example is piano tuners don't need to be piano players.. not sure.
1. all over this thread there are people swearing flat frequency response is crucial.
2. some posters in this thread and often a universally agreed conclusion in other threads is that flat response never sounds right at home.
Let's have a show of hands. Can't be both ways.
Footnote: a smooth frequency response (but not necessarily flat) is something different and I am sure few would doubt its importance.
Footnote: can't say as I've ever heard studio sound that I'd like to have playing a Mahler symphony or anything else at home. Contrary to naive first impressions, I don't think there really is a compelling reason why the recording engineer and producer need home-hifi sound in the studio in order to create recordings that sound great on home hifis. Maybe an example is piano tuners don't need to be piano players.. not sure.
My long term suspicion is that we want a flat power response.
I'm a former "typical" DIY speaker builder. It is all too common to build for a flat on axis frequency response ignoring anything off axis because "we don't sit off axis". I spent all too long convincing myself that room response was insignificant, and earlier on even too hard to deal with.
Using dome tweeters, as many of us do, whilst holding the above attitude, will result in dissatisfaction, I think we can now agree. Comments that some have made when listening to speakers with well controlled directivity are a relaxed midrange, which at first sounds like it shouldn't be right, but doesn't actually sound wrong. Virtual omnidirectionality at the lower end of the tweeters coverage in poorly designed speakers gives an edge to their sound that so, so many speakers have.
Ha ha, flat and smooth for me. Along with all my other essentials. Maybe we should have a pole?
Dan
Dan
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Thanks John! Agree with your comments.
I've seen your big OB rigs. A 15" mid would be preferable but getting the crossover right to a tweeter is hard, especially in the 1k - 5k range.
Is high sensitivity a goal for your designs? Given the importance of having a well thought out chain/system, higher sensitivity would allow for better quality amplification.
I've seen your big OB rigs. A 15" mid would be preferable but getting the crossover right to a tweeter is hard, especially in the 1k - 5k range.
Is high sensitivity a goal for your designs? Given the importance of having a well thought out chain/system, higher sensitivity would allow for better quality amplification.
Something tells me I don't want to see Cal dance......... there's just enough ladies interested in audio.
Dan
Dan
Nope, many tests have shown that flat power response always sounds way too bright. It would require rising on axis response.
David S.
What axis, 0 degree speaker axis? I don't listen there. Anyway, I've always been one to roll off the highs just a little.
The Salmi papers are Listening room influence on loudspeaker sound quality and ways of minimizing it. AES preprint #1871. And A New, Psychoacoustically More Correct Way of Measuring Loudspeaker Freqquency Response. AES preprint #1963
He measures response in a live room with an exponential decay time window (puts measurement emphasis on the early part of the sound). The measuring gate is also longer for low frequencies and shorter for high frequencies.
"the device performs weighting of room reflections depending on their delay compared to the direct sond. The correlation seems to be better than that of any other known measurement method."
David S.
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