Exactly!
Isobaric = cancelled harmonics.
BP4 enclosure = lower distortion than direct radiator due to less movement per a given voltage.
And, I got force cancelling with the driver alignment.
"My Crown Vic's boomin' with the trunk of funk
All the jealous punks can't stop the dunk!"
Isobaric = cancelled harmonics.
BP4 enclosure = lower distortion than direct radiator due to less movement per a given voltage.
And, I got force cancelling with the driver alignment.
"My Crown Vic's boomin' with the trunk of funk
All the jealous punks can't stop the dunk!"
Your isobaric sub has nothing in common with the arrangement being discussed except that the drivers are facing each other. Acoustically they are very different.
My enclosure is the isobaric BP4 version of this enclosure.
My drivers are firing outward (which is force cancelling) instead of inward. As matter fact, I could have easily had a center firing port. I chose to do corner loading in the trunk.
My drivers are firing outward (which is force cancelling) instead of inward. As matter fact, I could have easily had a center firing port. I chose to do corner loading in the trunk.
I already own 4 of these woofers, picked them up for a lot less than that. They have good Xmax and I have plenty of watts available to drive them plus DSP if I need it, so not too worried about the QTS.
You will gain around 10dB of max output running them in separate U,H or W baffles instead of clamshell.
That speaker is from PAGE 1 of this thread.
I'm just responding to your statement "clamshell is a waste."
Technically, this pic is literally OPEN BAFFLE, H-frame, U-frame, clamshell, and force cancelling...ALL-N-1😉
Apologies....just reread your OP and missed the bit 'already owned'. The BMS should make a fine system, and as you are extending up to 200hz, the light cones should be fast and detailed. Let us know how they work out....
CHeers
Vic
^ Hi,
quick morning coffee commentary. Light weight cone association to "fast and detailed" is a simplification circulating around, it indicates the driver is optimized for mid or high frequency duty yeah, but if you lowpass and equalize a driver to a system, like one would do for a bass in a system context, the fast and detail would go away. Mms is one of seven fundamental TS parameters which all together describe a driver, not just the Mms.
So, if there is difference in sound between two drivers, it's there not saying that, but it's not likely the mass or any other single parameter because the whole driver is different.
In general, any driver can be optimized for some frequency band, and the better optimized for some particular bandwidth the less good it works on other duties outside of it. If you were designing drivers and optimize a driver for both sub and mid, well, perhaps the max SPL is sacrificed, it would not excel on either but be a compromise, perhaps good or a reasonable one. For example cone of a sub can be heavy because it lowers Fs and makes it more rigid to withstand big pressure and excursion, things that make a better sub. For midrange duty these are things that do not matter at all, low Fs is not needed, neither the rigidity, but perhaps better damping properties and stuff that is not related to huge x, like smaller gap and voice coil. Completely different things to optimize for. One can make a compromise between, some excursion capability with some midrange performance.
Building speakers get easier if one doesn't limit design freedoms by concentrating on details that might matter sometimes while sometimes they don't, so it's just random "I want" stuff, which has nothing to do with physics severely limiting finding a good compromise solution. Only the whole system matters so look things holistically, sometimes Mms is low, sometimes it's high, and the system could sound good or bad depending on 99 other things.
quick morning coffee commentary. Light weight cone association to "fast and detailed" is a simplification circulating around, it indicates the driver is optimized for mid or high frequency duty yeah, but if you lowpass and equalize a driver to a system, like one would do for a bass in a system context, the fast and detail would go away. Mms is one of seven fundamental TS parameters which all together describe a driver, not just the Mms.
So, if there is difference in sound between two drivers, it's there not saying that, but it's not likely the mass or any other single parameter because the whole driver is different.
In general, any driver can be optimized for some frequency band, and the better optimized for some particular bandwidth the less good it works on other duties outside of it. If you were designing drivers and optimize a driver for both sub and mid, well, perhaps the max SPL is sacrificed, it would not excel on either but be a compromise, perhaps good or a reasonable one. For example cone of a sub can be heavy because it lowers Fs and makes it more rigid to withstand big pressure and excursion, things that make a better sub. For midrange duty these are things that do not matter at all, low Fs is not needed, neither the rigidity, but perhaps better damping properties and stuff that is not related to huge x, like smaller gap and voice coil. Completely different things to optimize for. One can make a compromise between, some excursion capability with some midrange performance.
Building speakers get easier if one doesn't limit design freedoms by concentrating on details that might matter sometimes while sometimes they don't, so it's just random "I want" stuff, which has nothing to do with physics severely limiting finding a good compromise solution. Only the whole system matters so look things holistically, sometimes Mms is low, sometimes it's high, and the system could sound good or bad depending on 99 other things.
Agreed, it was a simplification I was making comparing specifically my UM18's to the OP's BMS. Mine are operating up to 60hz, the OP's up to 200hz. I would put out there that the heavier cones of the UM18 would be better at reproducing the deeper frequencies than the lighter cones of the BMS, also because the Fs goes lower.
I can verify that I had the UM18's previously operating in my system up to 200hz. I have now handed this over to a boxed passive radiator system which is giving me more slam & detail than the UM18's ever did. My passive radiators will go lower, but then they incite room modes, so I am handing over to the naked UM18 clamshells that take it down to 20hz, WITHOUT inciting room modes.
Whether the naked clamshell BMS's will match the passive boxes radiators for slam and detail, I dont know.....and neither will you unless you try it. I speculate they wont.
I can also verify while developing this system, that the efficient, fabric surround, light coned coned PA variety of speaker (and I tried many, including AE Dipole 18, Goldwood, PRV & others) never gave me the bass I wanted. It wasn't until I tried the inefficient, heavy coned, rubber surround Daytons IB & RSS 15's that I started to get real bass from this naked format. The UM18 was a revelation in this regard and better than anything I tried before. The clamshell was a later development.
I can verify that I had the UM18's previously operating in my system up to 200hz. I have now handed this over to a boxed passive radiator system which is giving me more slam & detail than the UM18's ever did. My passive radiators will go lower, but then they incite room modes, so I am handing over to the naked UM18 clamshells that take it down to 20hz, WITHOUT inciting room modes.
Whether the naked clamshell BMS's will match the passive boxes radiators for slam and detail, I dont know.....and neither will you unless you try it. I speculate they wont.
I can also verify while developing this system, that the efficient, fabric surround, light coned coned PA variety of speaker (and I tried many, including AE Dipole 18, Goldwood, PRV & others) never gave me the bass I wanted. It wasn't until I tried the inefficient, heavy coned, rubber surround Daytons IB & RSS 15's that I started to get real bass from this naked format. The UM18 was a revelation in this regard and better than anything I tried before. The clamshell was a later development.
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Studley, I spent decades messing with speakers....open baffle, no baffle, full range etc.
I went full circle & came back to boxed speakers figuring these were the best for my listening criteria. I retained the naked clamshell though, as these gave the best bass in my room.
Regarding boxed speakers, I couldn't be arsed to make my own and went through over a dozen commercial 'bookshelf' offerings. Integrating the sub in my room took ages to get the crossover to my satisfaction. I eventually got there with a pair of active Focal Shape Twin studio monitors. The Focal Shapes are unique in using passive bass radiators rather than ports. I went active for several reasons, but the main one was the HPF so I could control the bass output and cleanly integrate with my UM18's. I found the speakers with ports (even though active with high pass filters), did not give a clean cut, and the air coming out of the ports was smearing the integration.
I am not saying this is a path everyone should take. I happen to be rather OCD in this regard as I listen to a lot of electronic music where much is happening at that crossover frequency.
I went full circle & came back to boxed speakers figuring these were the best for my listening criteria. I retained the naked clamshell though, as these gave the best bass in my room.
Regarding boxed speakers, I couldn't be arsed to make my own and went through over a dozen commercial 'bookshelf' offerings. Integrating the sub in my room took ages to get the crossover to my satisfaction. I eventually got there with a pair of active Focal Shape Twin studio monitors. The Focal Shapes are unique in using passive bass radiators rather than ports. I went active for several reasons, but the main one was the HPF so I could control the bass output and cleanly integrate with my UM18's. I found the speakers with ports (even though active with high pass filters), did not give a clean cut, and the air coming out of the ports was smearing the integration.
I am not saying this is a path everyone should take. I happen to be rather OCD in this regard as I listen to a lot of electronic music where much is happening at that crossover frequency.
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Hi,
What happens, for instance foe aesthical reasons in an broken clamshelll where the magnet are back to back, always coupled by the rods ?
Is the gap between the drivers now too wide and the +4/6 dB is lost ? As the H3 cancelation of push-pull typology ?
Like I see it also reading the thread, also a 15" in an half ball could do an aesthical U frame ! Challenge is to find that (Ikea have no balls of prestige as wide !)
Is for instance a single 18" as good or better than a 15" x2 clamshelll.
@bushmeister, very cool work you made on the whole metal frame ! 🙂
@cowanaudio : do you please know if the radiating patern is changing if such a clamshell is changing if one flip vertically the clamshell to face the slot horizontally, not cardioid anymore ?
Same, but this time flipped horizontally like in the picture but the slot towards the listening position instead of the sides like in post 1 ?
Thanks
What happens, for instance foe aesthical reasons in an broken clamshelll where the magnet are back to back, always coupled by the rods ?
Is the gap between the drivers now too wide and the +4/6 dB is lost ? As the H3 cancelation of push-pull typology ?
Like I see it also reading the thread, also a 15" in an half ball could do an aesthical U frame ! Challenge is to find that (Ikea have no balls of prestige as wide !)
Is for instance a single 18" as good or better than a 15" x2 clamshelll.
@bushmeister, very cool work you made on the whole metal frame ! 🙂
@cowanaudio : do you please know if the radiating patern is changing if such a clamshell is changing if one flip vertically the clamshell to face the slot horizontally, not cardioid anymore ?
Same, but this time flipped horizontally like in the picture but the slot towards the listening position instead of the sides like in post 1 ?
Thanks
Diyiggy
Never tried the back to back configuration. I think it would lose directionality.
The clamshell configuration gives nulls at the sides so the pattern of bass is like a figure of 8. I think having this directionality is what makes it room friendly.
I have tried different orientations. The one that works for me is having the magnets aligned with the listening axis. Could be my room as my speakers are place along the wide wall in a rectangular room approx 7 x 5m. I know one guy that places magnet on floor and it works for him.
The output from a single 18" vs 15" clamshell would not be so room friendly as less controlled:
Never tried the back to back configuration. I think it would lose directionality.
The clamshell configuration gives nulls at the sides so the pattern of bass is like a figure of 8. I think having this directionality is what makes it room friendly.
I have tried different orientations. The one that works for me is having the magnets aligned with the listening axis. Could be my room as my speakers are place along the wide wall in a rectangular room approx 7 x 5m. I know one guy that places magnet on floor and it works for him.
The output from a single 18" vs 15" clamshell would not be so room friendly as less controlled:
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It is not very pretty eyes-wise according my tastes, but I think an open frame shell could be printed in order to make a socket with black fabric like a clssic loudspeaker. Could look like a flipped Zepelin from B&W, according where you length the apex from the back magnets.
Ah, yup, if one flip 180° the null will be in front of the listeners.... okay, bad idea from me !
Ah, yup, if one flip 180° the null will be in front of the listeners.... okay, bad idea from me !
It would be interesting to find out if you experienced the same subjective bass sound quality with an h frame etc vs your current setup.