If the bass horn is near or on the floor and the midrange horn is crossed over at the right place (around 250 cycles) the fundamentals have a much better chance of not being interfered with and you have no nasty hole in the middle of your upper bass low midrange. It's pretty simple if you design your system with the room in mind to begin with. Allison did this with his direct radiators.
When you think about how most recordings are made these days with close miking techniques you would come to the conclusion that the floor bounce would be greatly attenuated from the actual in-room sound. Does it matter if your speakers are producing this in the reproduction of that music, or is it actually correct that your speakers do create this missing information that we do normally hear in normal life? This may actually be what is behind the preference of some for smaller monitor speakers on stands. This notch being spoken of at 250hz could actually be what you would hear if you were in the space where the music is being produced depending on where and how far away you are from the speakers and the in-room blending that would be going on. There are as many contradictory thoughts about how we hear that I doubt that this question will ever be completely answered with our limited understanding about how we hear and how the brain actually processes this information. We do make a lot of blanket statements in audio that I just question as to the real validity of the conclusions based on our limited knowledge of the hearing process. Measured distortion with electrical analysis may have little to do with our actual ear brain feedback loop and any processing we may do in our brains. Sorry but I don't believe that modern science has the correct model to use at this point to understand why we prefer certain sounds and dislike others. Just my opinion here.
At the same time that we speak of the floor bounce from a stand mounted monitor is is just as discomforting to me that with the current system that Lynn and others are working on that the spread distances between devices is given such short shift in what that does to our perception, I personally cringe every time I see one of those distributed horn systems with horns on different vertical and horizontal axis. Then again I think the same about such large horns forcing the center to center distances so far apart, this is the exact opposite of the thinking of the coaxial designs, there is no real best solution in my eyes, only a set of compromises. And remember that I do actually work with both types of systems, direct radiator and horn loaded. Each has its own sonic signature and good and bad points. You have to chose your poison well to satisfy your own personal preferences. I do appreciate the statement that Lynn made the other day that his system is meant for a specific type of amplifier and even the source material listened to. I'm not much on vacuum tube amplification but have enjoyed it with certain systems where it was optimized, it is just that you have a more limited amount of possibilities to get that synergy right. Without high efficiency speakers it is a fail in my eyes, with horns and compression drivers and large high efficiency cone drivers Lynn's design makes sense.
At the same time that we speak of the floor bounce from a stand mounted monitor is is just as discomforting to me that with the current system that Lynn and others are working on that the spread distances between devices is given such short shift in what that does to our perception, I personally cringe every time I see one of those distributed horn systems with horns on different vertical and horizontal axis. Then again I think the same about such large horns forcing the center to center distances so far apart, this is the exact opposite of the thinking of the coaxial designs, there is no real best solution in my eyes, only a set of compromises. And remember that I do actually work with both types of systems, direct radiator and horn loaded. Each has its own sonic signature and good and bad points. You have to chose your poison well to satisfy your own personal preferences. I do appreciate the statement that Lynn made the other day that his system is meant for a specific type of amplifier and even the source material listened to. I'm not much on vacuum tube amplification but have enjoyed it with certain systems where it was optimized, it is just that you have a more limited amount of possibilities to get that synergy right. Without high efficiency speakers it is a fail in my eyes, with horns and compression drivers and large high efficiency cone drivers Lynn's design makes sense.
Newbie Speaker Build Part 1
Thanks a lot for your feedback. Needless to say, auditioning multiple designer systems at RMAF or other such venues would likely offer a great advantage for determining what specific configurations of speaker/amplifier technologies my ear/brain truly favors. However, as there are long distance travel and related issues, attending most audio shows are not an option (When was the last high end audio show held on Long Island? Did it ever even happen?). Thus, as it was for my amplifiers, much of what influenced my decision making came from reviews by those or contracted by those of long time standing (and who also attend many RMAF events), the designer’s philosophy and reputation, what I’ve been fortunate to learn from select forums like this one, together with my own knowledge and powers of reasoning-and all of the above versus that highly unforgiving thing known as a budget. So, risky as it may be, a best informed “mix-and-match” approach to loudspeaker and amplifier selection seems to be my only route.
That said, I am again appealing for opinions here on three proposed “mix & match” HF/MF mains systems. Any of the mains below would be driven by my First Watt J2 amp and crossed with a pair of GPA Altec 416 midwoofers. The 416s would be driven by my First Watt F4 amp. The considered mains are:
1.) A pair of alnico tweeters with pair of alnico midrange drivers. They would be crossed at the speaker level with a crossover like this XM47 passive crossover for loudspeaker drivers
2.) A pair of ribbon tweeters with pair of alnico midrange drivers. Again, with these two
drivers and the Altec 416 midwoofers, and because I have only two stereo amps, they all would need to be crossed at the speaker level as above.
3.) ………..and now for something completely different: Whether it is cost, compatibility or performance, all speaker technologies have their limitations. Such is the case with electrostatic speakers, as discussed here The Art of Speaker Design Certainly, the few full range ES panels on the market have either received little scrutiny How Electrostats Work - Essence Electrostatic Speaker Systems
or have but are thoroughly unaffordable by most SOUND LAB
However, Sound Lab also has the MiniStat SOUND LAB The specs here say 8 ohms nominal impedance and a total system sensitivity of 94db. That would certainly seem to impose a relatively light load on my J2 amp (25 wpc 8 ohms/13 wpc 4 ohms)-and obviously an even lighter load with the MiniStat’s 6” woofer and speaker level crossover removed.
Sound Lab tells me that the MiniStat’s HF/MF ES panels are flat from 950Hz to 20kHz. Thus, with the right crossover type (Linkwitz-Reilly?) and a steep enough slope, I could cross these panels with the Altec 416 midwoofers between 900 and 1kHz-thereby avoiding the Altec 416’s dreaded glitch between ~ 1200Hz and 1600Hz, as shown here
http://www.greatplainsaudio.com/downloads/416-8B Spec Sheet.pdf
I have only two stereo amps, so I cannot do any tri-amping. But using these ES panels and the Altec 416s would be bi-amping, so I can instead cross them at line level, either passively like this XM46 Passive Line Level Crossover Network, PLLXO, 24 dB/oct or actively like this
http://www.firstwatt.com/pdf/prod_b4_man.pdf Either way avoids amplifier power losses (crucial for the tiny J2 amp) and potential sonic coloration from speaker level crossovers.
But even when restricted to the HF & MF range, electrostatic speakers have their drawbacks, as the above article enumerates. In fact, as Sound Lab publishes neither frequency response nor impedance curves, nor do any seem to be available elsewhere (i.e. those often done on gear under test by Stereophile’s John Atkinson), I don’t even know if my J2 amp can drive the MiniStat panels (sans woofer and crossover) within the required range without distortion.
And even if that was no problem, can these particular ES panels-if only within the ~ 950Hz to 17kHz range-rival the imaging, sound staging of ribbon tweeters
and these particular midrange drivers?
Please share your thoughts.
Also, for systems 1 and 2 above, please try to suggest specific model HF and MF drivers (i.e. RAAL, SEAS, Fostex), and why perhaps those suggested would work best together. Thanks.
Thanks a lot for your feedback. Needless to say, auditioning multiple designer systems at RMAF or other such venues would likely offer a great advantage for determining what specific configurations of speaker/amplifier technologies my ear/brain truly favors. However, as there are long distance travel and related issues, attending most audio shows are not an option (When was the last high end audio show held on Long Island? Did it ever even happen?). Thus, as it was for my amplifiers, much of what influenced my decision making came from reviews by those or contracted by those of long time standing (and who also attend many RMAF events), the designer’s philosophy and reputation, what I’ve been fortunate to learn from select forums like this one, together with my own knowledge and powers of reasoning-and all of the above versus that highly unforgiving thing known as a budget. So, risky as it may be, a best informed “mix-and-match” approach to loudspeaker and amplifier selection seems to be my only route.
That said, I am again appealing for opinions here on three proposed “mix & match” HF/MF mains systems. Any of the mains below would be driven by my First Watt J2 amp and crossed with a pair of GPA Altec 416 midwoofers. The 416s would be driven by my First Watt F4 amp. The considered mains are:
1.) A pair of alnico tweeters with pair of alnico midrange drivers. They would be crossed at the speaker level with a crossover like this XM47 passive crossover for loudspeaker drivers
2.) A pair of ribbon tweeters with pair of alnico midrange drivers. Again, with these two
drivers and the Altec 416 midwoofers, and because I have only two stereo amps, they all would need to be crossed at the speaker level as above.
3.) ………..and now for something completely different: Whether it is cost, compatibility or performance, all speaker technologies have their limitations. Such is the case with electrostatic speakers, as discussed here The Art of Speaker Design Certainly, the few full range ES panels on the market have either received little scrutiny How Electrostats Work - Essence Electrostatic Speaker Systems
or have but are thoroughly unaffordable by most SOUND LAB
However, Sound Lab also has the MiniStat SOUND LAB The specs here say 8 ohms nominal impedance and a total system sensitivity of 94db. That would certainly seem to impose a relatively light load on my J2 amp (25 wpc 8 ohms/13 wpc 4 ohms)-and obviously an even lighter load with the MiniStat’s 6” woofer and speaker level crossover removed.
Sound Lab tells me that the MiniStat’s HF/MF ES panels are flat from 950Hz to 20kHz. Thus, with the right crossover type (Linkwitz-Reilly?) and a steep enough slope, I could cross these panels with the Altec 416 midwoofers between 900 and 1kHz-thereby avoiding the Altec 416’s dreaded glitch between ~ 1200Hz and 1600Hz, as shown here
http://www.greatplainsaudio.com/downloads/416-8B Spec Sheet.pdf
I have only two stereo amps, so I cannot do any tri-amping. But using these ES panels and the Altec 416s would be bi-amping, so I can instead cross them at line level, either passively like this XM46 Passive Line Level Crossover Network, PLLXO, 24 dB/oct or actively like this
http://www.firstwatt.com/pdf/prod_b4_man.pdf Either way avoids amplifier power losses (crucial for the tiny J2 amp) and potential sonic coloration from speaker level crossovers.
But even when restricted to the HF & MF range, electrostatic speakers have their drawbacks, as the above article enumerates. In fact, as Sound Lab publishes neither frequency response nor impedance curves, nor do any seem to be available elsewhere (i.e. those often done on gear under test by Stereophile’s John Atkinson), I don’t even know if my J2 amp can drive the MiniStat panels (sans woofer and crossover) within the required range without distortion.
And even if that was no problem, can these particular ES panels-if only within the ~ 950Hz to 17kHz range-rival the imaging, sound staging of ribbon tweeters
and these particular midrange drivers?
Please share your thoughts.
Also, for systems 1 and 2 above, please try to suggest specific model HF and MF drivers (i.e. RAAL, SEAS, Fostex), and why perhaps those suggested would work best together. Thanks.
What would you propose for a midrange driver from 250 on up? One that is in production.
There are a few cones that work well in horns in the 5 to 8" category but not many will do a decade. I use the jbl cmcd-82h - there are other compression drivers that will work that low and not sound strained or thin but they cost many thousands of dollars - cones make sense if you can deal with the bandwidth extension on top
I've already bought the TD4001 so what the hell lets hear about these exotic CDs that work well that low
The plan was not to push the TAD too far low when they start to sound strained, but at the same time not have to use a midbass horn that extends too high up in the midrange. Which is why I'm intrigued by your idea of a lower midrange horn.
I can't say I have ever used any of those real exotic compression drivers that work that low. I have used the Emilar EC600 (not in business anymore) that had a 6" dome and 3" exit and once used the Adamson kevlar compression driver - 10" with phase plug - with the TAD 4001. This has been something I've been working on for around 15 years - The JBL CMCD 8" drivers are better than either of those. They have better low mid response (warm and full of tone - i like that) and are less ragged towards the top end (2.2K)
With the 4001 the problem is everybody wants to extract the widest bandwidth out of it (me included) - if you do that you will probably find crossing it below 800 cycles where the horn gets too big to deliver the upper range as well as a separate treble horn. using it 800-1000 up is probably abetter idea with a smaller horn. I used 550 round Edgar tractrix horns with mine and it was delightful - below that was the TAD 1201 in a 100 Hz tractrix - this was crossed at 900 cycles - from 150 cycles up the system was heaven
The JBL CMCD 8" drivers are better than either of those. They have better low mid response (warm and full of tone - i like that) and are less ragged towards the top end (2.2K)With the 4001 the problem is everybody wants to extract the widest bandwidth out of it (me included) - if you do that you will probably find crossing it below 800 cycles where the horn gets too big to deliver the upper range as well as a separate treble horn. using it 800-1000 up is probably abetter idea with a smaller horn. I used 550 round Edgar tractrix horns with mine and it was delightful - below that was the TAD 1201 in a 100 Hz tractrix - this was crossed at 900 cycles - from 150 cycles up the system was heaven
Personally I would not use a compression driver down to 250hz, I have never heard one that sounds good that low, ever! If you use a large format driver like a large old Altec or JBL 2" exit then you have to cut it anyway to get into the high frequency driver so why is that better than using a cone for the mids, and you can use a horn loaded cone to do that job. To say they won't cover a decade is just plain wrong, I have done it many times, it is just that if you are using a compression driver for the top end you c an get low enough that the mid cone driver does not need to cover all that much, you have to chose you crossover point somewhere were both horns integrate well with each other. I mean if you really want to use and old Altec 311 horn for mids go for it, but just understand that this is one way to get back to that nasal horn sound that is so disliked by so many and why horns have had such a bad rap for so long. When I worked in pro-audio PA application this was an area that was really well understood and we did everything possible not to use compression drivers that low, of course the spl levels are much greater and the distortions become much more evident when you push the systems. I developed my first cone driven mid range horns in 1976 just to overcome those compression driver limitations. Nothing has changed as far as I a concerned, still the same problems with large diameter compression driver diaphragms there have always been.
https://www.jblpro.com/ProductAttachments/CMCD_TechNote.pdf
An externally hosted image should be here but it was not working when we last tested it.
POOH,
Are you using that JBL as a compression driver or as just a direct radiator? They did what I did with a normal cone driver by having a closed back, I did that with a sealed chamber. That looks like a better solution than a large format 2" compression driver with a proper designed horn to go with it.
Are you using that JBL as a compression driver or as just a direct radiator? They did what I did with a normal cone driver by having a closed back, I did that with a sealed chamber. That looks like a better solution than a large format 2" compression driver with a proper designed horn to go with it.
Joshk,
It seems to me that any high quality 15" bass driver should be capable to get up to 1Khz before things start to get iffy. But it is so easy to get up to the 500-600hz range with a good 15" why would you truly need to run a mid-horn any lower than that? A horn in that range does not have to be that large, it becomes very practical to make a horn in that size and integrate it with a high frequency horn and 1" c0mpression driver. I understand that many chose their cross-over points trying to keep the point out of certain ranges but that has more to do with the individual devices used that I often question that thinking. If the transition between devices is smooth with similar dispersion at that frequency and without strange phase relationships I don't think that is as important as some seem to put emphasis on that point.
It seems to me that any high quality 15" bass driver should be capable to get up to 1Khz before things start to get iffy. But it is so easy to get up to the 500-600hz range with a good 15" why would you truly need to run a mid-horn any lower than that? A horn in that range does not have to be that large, it becomes very practical to make a horn in that size and integrate it with a high frequency horn and 1" c0mpression driver. I understand that many chose their cross-over points trying to keep the point out of certain ranges but that has more to do with the individual devices used that I often question that thinking. If the transition between devices is smooth with similar dispersion at that frequency and without strange phase relationships I don't think that is as important as some seem to put emphasis on that point.
At the moment, this is just a thought experiment. I have the JBL CMCD drivers on hand and was wondering how low they can go on an appropriate horn and what top end they extend to (mass corner and all that). The FS is stated as 320hz, so I assume that you wouldn't want to use these lower than say 0.7*Fs.
JoshK,
If I was to use that cone driver on a horn and actually went as low as 325HZ I would surely move up to an 18" cone on the bottom to take advantage of the greater cone area and low bass output. With that as the upper frequency of the bass speaker no reason to lock yourself into a 15" as you wouldn't have a problem getting up to 325hz with an 18" driver. To me that is the wiser choice than using two 15" cones for low bass and having to integrate those two devices. Again just my opinion.
If I was to use that cone driver on a horn and actually went as low as 325HZ I would surely move up to an 18" cone on the bottom to take advantage of the greater cone area and low bass output. With that as the upper frequency of the bass speaker no reason to lock yourself into a 15" as you wouldn't have a problem getting up to 325hz with an 18" driver. To me that is the wiser choice than using two 15" cones for low bass and having to integrate those two devices. Again just my opinion.
Hi Lynn,
Not sure I understand this....When ever I listen to live music there can be no floor bounce....The drum kit is on the stage floor...No floor bounce from floor mounted drums (like a floor mounted sub woofer) or Cello etc....
Also the majority of stage arrangements / orchestra layout / audience seating means that the majority ( every audience member bar the front row) has a great " anti floor bounce " acoustic treatment....Ie the rows of seating and bodies in front!
Even in smaller pub / club settings with the PA stack on the floor and a standing audience, only the front row of the audience would get some floor bounce from the PA mid and top sections.
A floor to ceiling (or min 75%of the floor to ceiling height) eliminates any floor bounce, or at least renders it in audible.
Sorry if I am missing something?
Cheers
Derek.
Overkill,
Except for the kick drum all the other drums and cymbals in a drum kit are in the air, how can there not be a floor bounce? The same with any speaker that is not sitting on the floor, usually only a bass speaker would be close to the floor all the other devices would be at ear level usually and again how could you not have a floor bounce unless the floor absorbed the bounce somehow?
Except for the kick drum all the other drums and cymbals in a drum kit are in the air, how can there not be a floor bounce? The same with any speaker that is not sitting on the floor, usually only a bass speaker would be close to the floor all the other devices would be at ear level usually and again how could you not have a floor bounce unless the floor absorbed the bounce somehow?
Audience are absorbers....!
Hi K,
Unless you are in the front row, the audience (and padded chairs if seated) act as very effective absorbers....
The "direct line of sound" will be straight from any raised speakers / instruments direct to the listeners ears.
If you were sitting at home with a reflective floor between you and your stand mounted speakers you would have a floor bounce.....
Now fill in that hard floor with soft bodies and padded seating.....No floor bounce.
Cheers
D.
Hi K,
Unless you are in the front row, the audience (and padded chairs if seated) act as very effective absorbers....
The "direct line of sound" will be straight from any raised speakers / instruments direct to the listeners ears.
If you were sitting at home with a reflective floor between you and your stand mounted speakers you would have a floor bounce.....
Now fill in that hard floor with soft bodies and padded seating.....No floor bounce.
Cheers
D.
Overkill,
In a home environment you could indeed use carpet and other soft surfaces to absorb some of the floor bounce but I doubt very much that a carpet would be a very wide band absorber and much of the bounce would still occur. This is no different than those who believe that one of those corner sound absorbers actually can cut the very low bass, not going to happen. Even in a live concert where the performers are up on the stage the floor bounce is still going to happen, not in the way I think you are thinking, I think it would be more of a smearing of images due to the different path length before the sound gets to your ears. Certainly it would be different than sitting in front of a speaker at home.
In a home environment you could indeed use carpet and other soft surfaces to absorb some of the floor bounce but I doubt very much that a carpet would be a very wide band absorber and much of the bounce would still occur. This is no different than those who believe that one of those corner sound absorbers actually can cut the very low bass, not going to happen. Even in a live concert where the performers are up on the stage the floor bounce is still going to happen, not in the way I think you are thinking, I think it would be more of a smearing of images due to the different path length before the sound gets to your ears. Certainly it would be different than sitting in front of a speaker at home.
They are in 180 flare tractrix, I'm building some 120 flare hypex for them though - I use them as a compression driver with the factory phase plug - int the low midrange they are the best I've heard - I have a a wall full of large format (2") drivers. In these horns they work best in my system 250 to 1200 cycles - the mains are horn loaded 4-way plus the horn subs and line array/rear subs LOL