Hi JCX,
The reason other members are showing their frustration is that your ignoring the successful operational history of full-range and your also quoting Klippel out of context. You continue to ignore other factors, an indication of a lack of wide-band driver design knowledge.
For the record: Dr. Wolfgang Klippel met me in Hong Kong some years back. We had a supportive set discussions on driver design and operation. We discussed Markaudio driver design technology during this time, with a view to Markaudio using his test technology at some point in the future. At no point were there any suggestions from him that single cone full-range and single cone extended full-range drivers would become effectively in-operable due to output modulation variation (Dopler et al).
All experienced professionals like myself and Wolfgang recognise that phenomena like these are largely mitigated by practical application and not measurable "absolutes" upon which all loudspeaker design and operations should completely rely.
Member Bigun has better understood the operational reality of this phenomenon:
"Describing it as phase modulation turned on some light bulbs for me (as opposed to Doppler) - I think I can see where phase modulation can arise - the creation of successive peaks of the sound waves can occur when the cone surface is closer or further from the listener and this difference in distance translates to a difference in phase of the peaks. The distance the cone moves however is typically tiny so the phase modulation is also tiny and there are other distortion contributors in any speaker that are more important to pay attention to than this."
The essential point about most drivers is that many of the factors that come up for debate (Dopler and other various distortion issues) require members to properly appreciate the designer's operational performance goals for the driver.
Clearly, drivers taken close to, or outside their design limits will emit some or all of the phenomena mentioned in this thread. However, those members who apply themselves to sensibly matching the driver to the box and the boxes to their listening room size will likely not have any such audibility issues.
So JCX, you need to appreciate the context in which drivers operate rather than continue to "skew" the debate and then complain when other members are giving you encouragement to apply a more practical rationale.
Mark.
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after spending 2 months with alpairs 10.2 in small boxes and now in M10-A10, i believe that i am enjoying the music a lot with these speakers. i really think Bob should remove or modify the content on Will You Like My Speakers?
as it somewhat 'discourages' (especially the beginners who have never heard fullrange drivers) in my humble opinion!
as it somewhat 'discourages' (especially the beginners who have never heard fullrange drivers) in my humble opinion!
I have allot of sympathy with Bob's comments. In particular:
"Single-driver speakers are not for everyone. Single-driver speakers are about finesse, not power. Any speaer, sigle driver, 2-way, 3-way. whatever is a compromise. Each will have sonic advantages and failings. Therefore, you will wind up choosing speakers that work well with the bulk of your library and OK with the rest. There just isn't a speaker outh there that play everything well."
I think Bob's other comments, especially those referring to modulation should be read in the context of more traditional full-range driver designs. In particular the high efficiency short stroke types and those using secondary emitting devices (whizzers et al). Bob has recently (around a year) turned to using Markaudio drivers so we should give him time to appreciate the operational differences between the new breeds of ultra low mass, long throw, wide dispersion emitters (Markaudio et al) and earlier designs from traditional full-range makers.
Anyone who believes that multi-way systems somehow are immune from modulation issues are critically mistaken. I well know the problems of phase differential between different drivers deployed in multiway, but also the significant signal variances between larger oscillatory emitters when deployed with resonant units (tweets). There really is No Free Lunch in the loudspeaker world.
Thanks
Mark.
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I would like to give more food for thought. We know that pistonic drivers are highly inefficient because of poor coupling with atmosphere.
What does it mean in practice? When piston is moving forward it creates a zone of high pressure. In next (backward) phase, almost all this pressure will be consumed by piston back, and only small part of pressure changes travels toward listener.
We know that sound speed depends on air pressure. Also we can say that there is a medium, before diaphragm, where pressure deviations have pretty significant ratings and variable sound propagation .
And when we speak about Doppler Effect or acoustic phases the influence of this high pressure zone must be taken into account. We even could say that, the speaker diaphragm is not geometrical source of sound. The source is this medium, if only it wasn’t such blurred and dependant on waste numbers of variables.
What does it mean in practice? When piston is moving forward it creates a zone of high pressure. In next (backward) phase, almost all this pressure will be consumed by piston back, and only small part of pressure changes travels toward listener.
We know that sound speed depends on air pressure. Also we can say that there is a medium, before diaphragm, where pressure deviations have pretty significant ratings and variable sound propagation .
And when we speak about Doppler Effect or acoustic phases the influence of this high pressure zone must be taken into account. We even could say that, the speaker diaphragm is not geometrical source of sound. The source is this medium, if only it wasn’t such blurred and dependant on waste numbers of variables.
I've some sympathy with the points you raise, especially in relation to high-mass sub woofer and higher mass bass units. These types of driver in musical output terms are problematic.
However, the debate is less clear if we consider these units for more "effect" when being deployed in Home Theatre setups or where the music is overtly commercial in nature (rock, house etc), repetitive and meant to be played loud. Then there is little choice for the driver designer. He/she has to build the driver strong like a Victorian lavatory, applying lots of metal and other materials while likely lamenting the waste of increasingly precious commodities.
Cheers
Mark.
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see it in this way. We can put most and least efficient speakers in same, inefficient class. I would expect that Doppler Effect will be most obvious with horns, but who uses them as full range? Ordinary designs will produce very minor effect because of the surface of membrane is just part of mechanism and real sound source is pressure formed on the speaker’s baffle.
You have to understand why I put that disclaimer on my web site. I get daily inquiries about my products, the bulk from those with absolutely zero idea about what goes into designing a speaker or any other piece of audio gear for that matter. They fall into two camps: 1) "I'm unhappy with my current speakers so I thought I would give a full-range speaker a try." 2) "I just bought a pair of XYZ drivers and I want to know if they will work in one of your designs." The second class is easy. Send me your drivers and a few hundred bucks and I'll cobble up a strawman and let you know. For the first class, I need to ask some serious questions. Note that you cannot buy a pair of speakers directly from the web site. That is for one very good reason. The last thing that I can stand is to have to eat the return of a $2000 pair of speakers.
I will not sell speakers to anyone who requires 100dB at the listening chair or who tells me that they listen to a lot of metal, etc, or who listens to romantic symphonies at concert levels. The Fostex and Lowther designs simply can't do it, and the MA drivers, while they might for a while, would probably be destroyed.
I understand the concepts of Doppler/Am/FM/PM distortion. It is, however, next to impossible to get these across to someone who is into kilo-buck cables. Everyone can grasp the concept of (true) Doppler distortion. The physical reality that in speakers it's PM is not going to be understood. So, I took the argument to the FM level and let it lie.
I am aware that MA drivers can be played lower and louder than say a comparable Fostex. I can get into the 30's with the A7.3, but not very loud. Not loud enough to be satisfying in my 20'x25' room. The A10.2 will go lower louder, but not with the finesse of the A7.3. I have a preorder in for the A10P's. I have great expectations!
I like organ music. A lot of organ music has 32' stop tones. My dream speaker will do 90dB at 20Hz. It doesn't have to produce more that 90dB anywhere. Just in-room flat to 20. I have alluded to a proposed FAST speaker in the past, but this I am going to attempt this summer. Either the A7.3 or the A10P on top and whatever is needed on the bottom. The configuration will be a sub that serves as a stand for the top. This will be fun.
Bob
I will not sell speakers to anyone who requires 100dB at the listening chair or who tells me that they listen to a lot of metal, etc, or who listens to romantic symphonies at concert levels. The Fostex and Lowther designs simply can't do it, and the MA drivers, while they might for a while, would probably be destroyed.
I understand the concepts of Doppler/Am/FM/PM distortion. It is, however, next to impossible to get these across to someone who is into kilo-buck cables. Everyone can grasp the concept of (true) Doppler distortion. The physical reality that in speakers it's PM is not going to be understood. So, I took the argument to the FM level and let it lie.
I am aware that MA drivers can be played lower and louder than say a comparable Fostex. I can get into the 30's with the A7.3, but not very loud. Not loud enough to be satisfying in my 20'x25' room. The A10.2 will go lower louder, but not with the finesse of the A7.3. I have a preorder in for the A10P's. I have great expectations!
I like organ music. A lot of organ music has 32' stop tones. My dream speaker will do 90dB at 20Hz. It doesn't have to produce more that 90dB anywhere. Just in-room flat to 20. I have alluded to a proposed FAST speaker in the past, but this I am going to attempt this summer. Either the A7.3 or the A10P on top and whatever is needed on the bottom. The configuration will be a sub that serves as a stand for the top. This will be fun.
Bob
I haven't read the thread or anything about the facts behind this kind of distorsion. But I know that heavy rock music does sound really bad on my Mar-Kel70 speakers, even at relatively low levels. Less complex music sounds fantastic though.
Compared to my current bigger speakers the Mar-Kel70 handles simple music much better but complex music is better played by the bigger three-driver speakers I have at the moment.
But after all it's quite logical. A single driver can't play too many frequencies at once without sounding really bad. But it can play a few frequencies at once and doing it really good, better than multiple drivers would.
Compared to my current bigger speakers the Mar-Kel70 handles simple music much better but complex music is better played by the bigger three-driver speakers I have at the moment.
But after all it's quite logical. A single driver can't play too many frequencies at once without sounding really bad. But it can play a few frequencies at once and doing it really good, better than multiple drivers would.
OK, how about "just the facts" of the post
How was Klippel misquoted? – spell it out after reading exactly what I've posted here
I never claimed full range are unlistenable - I was merely trying to "debug" a misunderstanding of the physics of "Doppler" FM, PM distortion
it is a real physical effect - it can catch up people somewhat familiar with linear modeling since it happens at the interface between the motion and the sound radiation
I think it is cool to understand how the separately (ideally) linear phenomena of electroacoustic driver motion, and of (ideally) linear sound radiation in air combine for a nonlinear effect
for easy re-reading: (added bold to text that was in the original post)
this distortion can be a minor effect but the OP seemed to want to know if it were real at all - it is real, and it can be a minor effect
I haven't gone beyond that at all in my posts
How was Klippel misquoted? – spell it out after reading exactly what I've posted here
I never claimed full range are unlistenable - I was merely trying to "debug" a misunderstanding of the physics of "Doppler" FM, PM distortion
it is a real physical effect - it can catch up people somewhat familiar with linear modeling since it happens at the interface between the motion and the sound radiation
I think it is cool to understand how the separately (ideally) linear phenomena of electroacoustic driver motion, and of (ideally) linear sound radiation in air combine for a nonlinear effect
for easy re-reading: (added bold to text that was in the original post)
this distortion can be a minor effect but the OP seemed to want to know if it were real at all - it is real, and it can be a minor effect
I haven't gone beyond that at all in my posts
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Klippel is not referring to driver operation in "real life" practical applications where full-range driver loads rarely exceed the level at which this issue becomes audible! He makes no claim or reference to any specific drivers tested, or to any blind trial outcomes that He conducted to examine the audible extent of the phenomena.
I was merely trying to "debug" a misunderstanding of the physics of "Doppler" FM, PM distortion
The Markaudio forum is a commercial section, primarily for the use of members to exchange information on ideas and practical uses of our drivers in their Diy projects. I'm happy to give allot of latitude but the focus has to remain on practical use. You need the "lounge" section:
The Lounge - diyAudio
For example: http://www.diyaudio.com/forums/lounge/200865-sound-quality-vs-measurements.html
Mark
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H Rullknufs,
There's no way for any small driver, small/medium multi-way or single full-range, to do justice to "heavy rock". You must size a system according to needs and uses.
From my memory, Dave/Chris didn't design the Mar-Kel70 for this type of heavy load. Try building the Pensil-70. You'll find CHR's in this box more able to deliver on this type of music (within reason).
Full range drivers "can and do" emit multiple frequency loads while sounding "good". They've been doing it for many years. What full-ranger's can't do is handle heavier loads so its a question of sensible application. Naturally, if heavy rock is to be played "loud" then small full-rangers like the CHR, or most all multi-way bookshelfer's aren't going to cope well.
Myself, Bob Brines, Scott, Chris-B, Dave (Planet 10) et al. do our best to "inform" (see Bob's last post) but in the end we have to rely on members and end-users doing enough research into their projects to select the right design for their needs. Or have even more fun by building both small and larger systems
Thanks
Mark.
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Hi Bob,
I'm 100% with you on this. Its important for system users to understand the abilities of various types of drivers and systems prior to investing.
I think the thread starter (soundnovice) read your disclaimer and became focused on the issue of frequency modulation as a sole/primary explanation on specific capabilities of Markaudio drivers (et al). Your intended audience group will likely find your modulation explanation technically difficult to comprehend.
I get asked questions on driver capability most every hour (growing email bag). The central issue is one of system capability in relation to room sizing. I hope you'll not take this the wrong way as I appreciate and respect the work you do; But maybe the comment on your page could be simplified so typical system buyers can more easily equate driver/box sizing/power requirements to their room size.
For most DIY members regularly contributing to the Markaudio section, they have a reasonable appreciation of modulation, distortion etc. etc. and apply practical application to their projects. Naturally, new members seek help and advice so its good to offer practical assistance when we have time.
Cheers
Mark.
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Chaps (chappesses - I was recently reminded by email that there are female hobbyists),
Debate is good but please lets focus on being practical, supporting each other, especially new newer members who want help with their projects.
The Markaudio section can handle comments and debate in context of practical application with a fair amount of latitude. But if like member JCX, you want to pursue a very focused argument in greater depth, the lounge forum and similar are the sections on Diyaudio designed for this purpose. Apologies chaps but its not possible for me, as the only driver maker willing to stick his neck on the line, to facilitate and/or assist every point of view and debate desire. I wish I could but it just aint possible.
Apologies to those members who become disappointed with my facilitation, support and moderation. I'm doing the best I can while having to manage my present circumstances.
Thanks
Mark
Debate is good but please lets focus on being practical, supporting each other, especially new newer members who want help with their projects.
The Markaudio section can handle comments and debate in context of practical application with a fair amount of latitude. But if like member JCX, you want to pursue a very focused argument in greater depth, the lounge forum and similar are the sections on Diyaudio designed for this purpose. Apologies chaps but its not possible for me, as the only driver maker willing to stick his neck on the line, to facilitate and/or assist every point of view and debate desire. I wish I could but it just aint possible.
Apologies to those members who become disappointed with my facilitation, support and moderation. I'm doing the best I can while having to manage my present circumstances.
Thanks
Mark
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i came across this at Will You Like My Speakers? page
"The nemesis of single-driver speakers is frequency modulation (FM) of the upper ranges by the bass. (Doepler distortion is a type of FM distortion, not the other way around.) A higher fequency becomes a warble tone, the frequency and depth of the warble depending on the frequency and driver displacement of the bass tone. The result is when there are many bass frequecies in the music, as the music becomes loud (more driver excusion) the upper ranges become harsh and tonally indistinct. The driver "falls apart""
does all fullrange drivers suffer this? or are there any exceptions?
any technique to tame this ?
well if you see my original post, none of my questions wanted to discuss the phenomenon of FM or doppler effect....
my questions didn't raised any objections against these concepts but i wanted to know if are there any alternates to tame the issue!? if there are any, then i would definitely want to give a try. i believe FAST could be one of the 'partial' solution as Bob pointed out (his dream project could be mine too!!
) thanks for all the replies Mark
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well if you see my original post, none of my questions wanted to discuss the phenomenon of FM or doppler effect....
my questions didn't raised any objections against these concepts but i wanted to know if are there any alternates to tame the issue!? if there are any, then i would definitely want to give a try. i believe FAST could be one of the 'partial' solution as Bob pointed out (his dream project could be mine too!!
thanks for all the replies Mark
Hi Sound,
Many thanks for this post as it answers my points about practicality, apologies that your thread got steered off.
Your asking at an interesting time as recent developments, particularly Alpair 10M and 10P with their arrestor technology are bass capable. Hence my efforts to further extend the emittance properties of their cones (mass reduction and wider dispersion properties in particular). The operational relationships between the interfacing of mechanical oscillation and semi-static/static resonance output are the most complex I've encountered in my time designing drivers. Here's a general guide to help out:
Most Diyer's appreciate that any small(er) driver won't cope well in bigger rooms or under heavier/higher loads from the amp. So thinking about driver selection and box type/design in relation to the listening room size is important. For single driver uses, Alpair 6's, CHR/P-70's and Alpair 7's are usually good on their own in smaller Bass Reflex/ bookshelf boxes in rooms up to 4 metre X 4 metres. However, if you fancy having more/extended bass, then Dave/Chris's most recent work has merits, see Dave's post No.38. Or an alternative is to look at Scott's Pensil series boxes. They do quite well in the bass department for most general musical applications. Either way, the prospect on encountering audible modulation in these circumstances in very rare. Provided the driver/box match is good and the room size is within the system's scope; you'll likely see less than 3-mm of cone movement on the lows, not enough to cause audible non-linear distortions or any other kind of phenomena.
For larger room spaces, Alpair 10 and 12 will be required. Bob Brines has given indications of his room size in relation to Alpair 12. This driver doesn't have the arrestor so Bob rightly suggested some caution. Certainly the Pensils, Bob's TL's et.al are the better way to go, especially if you want to have a deepish tidy bass thats transmitting actual LF detail. If you need more bass (for example to play rock music) adding a helper woofer (low mass if possible) is worth consideration.
Also think about your musical preferences. Users playing mostly vocals, classical and lighter music aren't likely to gain much from using additional woofs. Those listening to deep Jazz, contemporary, beat and rock music will likely benefit from using larger cabs and/or adding woofs.
Something thats always worth doing (within reason) is moderately over-sizing the system in relation to the room size. For example, in a 4 metres X 4 metres room, I'd likely be temped to use Alpair 10. Its usually better to have some driver/box performance spare capacity in hand.
Hope this helps
Thanks
Mark.
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Also, and all things considered, if there is a concern about driver size vs. room size, nearfield speaker positioning can have some significant advantages over simply providing more headroom. That kind of configuration can mitigate room reflections and (IMO) provide some of the very best imaging a system can reproduce.
My definition of nearfield varies from room to room. In my listening environment (approx 14 feet by 24 feet, give or take) the speakers are located about 6 - 7 feet from the listening position. Even the 7.3s perform very well in this environment as long as I'm not too aggressive.
My definition of nearfield varies from room to room. In my listening environment (approx 14 feet by 24 feet, give or take) the speakers are located about 6 - 7 feet from the listening position. Even the 7.3s perform very well in this environment as long as I'm not too aggressive.
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