Best cabinet for odd subwoofer driver

[Sir.Byrd]

I have a 9" Meiloon subwoofer driver with these parameters:
Fs = 26.92 Hz
Qms = 3.573
Vas = 42.94 liters
n(0) = .28%
Mms = 137.2 grams
Re = 7.38 ohms
Qes = .289
SPL = 86.42 dB SPL 1W/1m
Cms = .25mm/N
Piston Diameter = 210mm
Zmax = 98.58 ohms
Qts = .268
Le = 2.08mH
BL = 24.34

So far I've used online calculators and the best arrangement seems to be a band pass or a TQWT cabinet. Maybe a passive radiator would work as well. Sealed or ported or horn loaded just don't seem to work.
Could you guys try modeling this driver and let me know what the scoop is?

 

[Sir.Byrd]

TQWT is a bit big, but it claims F3 of 18 Hz, sounds good for a subwoofer, as apposed to the 70 Hz that is showing in the sealed models.

 

[DaveElton]

TQWT is a bit big, but it claims F3 of 18 Hz, sounds good for a subwoofer, as apposed to the 70 Hz that is showing in the sealed models.

Wow! a sealed box lost that much low-end?? I "usualy" prefer a sealed box too..may have to re-evaluate that..:scratch2:

 

[Sir.Byrd]

Yeah, this is a weird driver. Doesn't like ported cabinets either, needs a very long port.

 

[Sir.Byrd]

Also, forgot to mention that x-max is around 10mm.

 

[TerryO]

Wow! a sealed box lost that much low-end?? I "usualy" prefer a sealed box too..may have to re-evaluate that..:scratch2:

I guess I should jump in and mention that given the T/S parameters (especially the low Qts) of "that" driver, it would need EQ/Bass Boost to be viable in "any" sealed enclosure. There's nothing intrinsically wrong with that approach, given that we're trying to come up with a design that can use Will's driver. However, Will related privately that he'd rather not use active EQ. With EQ, it could achieve a pretty flat output to 28 Hz, provided the driver has sufficient excursion for the louder passages.
Naturally, if you like sealed bass or sub enclosures (I certainly do!) you would probably select a driver with a better chance of integrating with that approach.

There's no need to shy away from sealed cabinets based solely on this rather non-typical driver.

Best Regards,
TerryO

 

[DaveElton]

I guess I should jump in and mention that given the T/S parameters (especially the low Qts) of "that" driver, it would need EQ/Bass Boost to be viable in "any" sealed enclosure. There's nothing intrinsically wrong with that approach, given that we're trying to come up with a design that can use Will's driver. However, Will related privately that he'd rather not use active EQ. With EQ, it could achieve a pretty flat output to 28 Hz, provided the driver has sufficient excursion for the louder passages.
Naturally, if you like sealed bass or sub enclosures (I certainly do!) you would probably select a driver with a better chance of integrating with that approach.

There's no need to shy away from sealed cabinets based solely on this rather non-typical driver.

Best Regards,
TerryO

Thank you for the added info Terry:yes: A "senior" member on another forum and I years ago discussed this at some length (sealed vs vented preference) and came to the conclusion that my ears prefer the "better" transient response of a sealed enclosure to the more extended LF response that a vented box gives??:scratch2:

 

[TerryO]

Thank you for the added info Terry:yes: A "senior" member on another forum and I years ago discussed this at some length (sealed vs vented preference) and came to the conclusion that my ears prefer the "better" transient response of a sealed enclosure to the more extended LF response that a vented box gives??:scratch2:

Dave,
For many years I thought that ported subs were the way to go, until I finally realized that a sealed subwoofer's first order rolloff in the bass frequencies is nearly matched by the Room Gain (the car guys call it cabin gain) that you experience in an enclosed room. The older modeling software didn't account for this, so the sims always showed ported enclosures as having deeper bass extension, when in fact they may, in actual practice, have been dead even.
It certainly took me a long time to finally figure it out, but eventually figure it out I did.

Best Regards,
TerryO

 

[DaveElton]

Dave,
For many years I thought that ported subs were the way to go, until I finally realized that a sealed subwoofer's first order rolloff in the bass frequencies is nearly matched by the Room Gain (the car guys call it cabin gain) that you experience in an enclosed room. The older modeling software didn't account for this, so the sims always showed ported enclosures as having deeper bass extension, when in fact they may, in actual practice, have been dead even.
It certainly took me a long time to finally figure it out, but eventually figure it out I did.

Best Regards,
TerryO

Thank you again, I did not know that

 

[Altec]

Yeah, this is a weird driver. Doesn't like ported cabinets either, needs a very long port.

Greets!

Not really, if high SQ in general and horn loaded systems in particular are your driver loading preference. Having bass horn compression driver specs, ergo another way of saying small sealed or various [tapped] TL alignments also, the TQWT is just an optimum vented alignment morphed to its logical conclusion.

With a maximum TL/horn loading BW of ~ 4-186 Hz, the questions are how low, how big, how loud can you ‘afford’ and how much room gain is available? FWIW, other than low Qt driver IB manifolds, best compromise between SQ, size and bang/buck these days is some ‘flavor’ of tapped TL [TL with more low end gain BW] with internal damping typically being used to ~ blend it to the room.

GM

 

[michiganpat]

Dave,
For many years I thought that ported subs were the way to go, until I finally realized that a sealed subwoofer's first order rolloff in the bass frequencies is nearly matched by the Room Gain (the car guys call it cabin gain) that you experience in an enclosed room. The older modeling software didn't account for this, so the sims always showed ported enclosures as having deeper bass extension, when in fact they may, in actual practice, have been dead even.
It certainly took me a long time to finally figure it out, but eventually figure it out I did.

Best Regards,
TerryO

that's why when I'm playing around with modeling, I look at F10 as much as I do F3....a lot of times most drivers have nearly identical F10's in ported or sealed, due to the sealed's shallower roll-off....

now add in boundary reinforcement (i.e. putting it into a corner) and fun stuff happens.

if doing something passive, this woofer might work well in bandpass, and allow a very cheap (mostly if not entirely mechanical) low pass filter...

 

[TerryO]

that's why when I'm playing around with modeling, I look at F10 as much as I do F3....a lot of times most drivers have nearly identical F10's in ported or sealed, due to the sealed's shallower roll-off....

now add in boundary reinforcement (i.e. putting it into a corner) and fun stuff happens.

if doing something passive, this woofer might work well in bandpass, and allow a very cheap (mostly if not entirely mechanical) low pass filter...

Hi Pat,

In modeling an enclosure I like to see the F10 as well, for exactly the same reasons as you've mentioned. It certainly offers a better snap-shot of the driver's "character".

The use of a bandpass solution was also mentioned in an "off the air" conversation about Will's driver. That is another approach, although I personally don't like band pass solutions in general, due more to the exclusive and narrow application that is the result. Part of that is probably my tendency to be somewhat slipshod in the build process. Bandpass tends to demand fairly "tight" design parameters, which, if observed, yield a solution that may work in one particular situation very well, but aren't as capable (IMO) of a general application for a wide range of usage like the other solutions discussed.

Best Regards,
TerryO

 

[dnewma04]

Terry, your concern with bandpass is that it hides a lot of the beautiful bondo. It's time to come to terms with this...

 

[sreten]

For many years I thought that ported subs were the way to go, until I finally
realized that a sealed subwoofer's first order rolloff in the bass frequencies is
nearly matched by the Room Gain (the car guys call it cabin gain) that you
experience in an enclosed room. The older modeling software didn't account
for this, so the sims always showed ported enclosures as having deeper bass
extension, when in fact they may, in actual practice, have been dead even.
It certainly took me a long time to finally figure it out, but eventually figure
it out I did.

TerryO

Hi,

Except you can arrange a ported design to have quasi first order
roll-off that matches room gain even better than sealed, with
higher efficiency and much greater SPL at the low port frequency.

rgds, sreten.

 

[Altec Best]

Greets!

Not really, if high SQ in general and horn loaded systems in particular are your driver loading preference. Having bass horn compression driver specs, ergo another way of saying small sealed or various [tapped] TL alignments also, the TQWT is just an optimum vented alignment morphed to its logical conclusion.

With a maximum TL/horn loading BW of ~ 4-186 Hz, the questions are how low, how big, how loud can you ‘afford’ and how much room gain is available? FWIW, other than low Qt driver IB manifolds, best compromise between SQ, size and bang/buck these days is some ‘flavor’ of tapped TL [TL with more low end gain BW] with internal damping typically being used to ~ blend it to the room.

GM

Hey GM ! Isn't this what we found on my project though, that the sealed alignment was the same as the ported until we added length to the vent ?

BTW How things going ?

 

[TerryO]

Greets!

Not really, if high SQ in general and horn loaded systems in particular are your driver loading preference. Having bass horn compression driver specs, ergo another way of saying small sealed or various [tapped] TL alignments also, the TQWT is just an optimum vented alignment morphed to its logical conclusion.

With a maximum TL/horn loading BW of ~ 4-186 Hz, the questions are how low, how big, how loud can you ‘afford’ and how much room gain is available? FWIW, other than low Qt driver IB manifolds, best compromise between SQ, size and bang/buck these days is some ‘flavor’ of tapped TL [TL with more low end gain BW] with internal damping typically being used to ~ blend it to the room.

GM

Thanks Greg,

Somewhere along the line I convinced myself that Will desired a more compact solution, which after reviewing the e-mails, doesn't seem to have been the case.

If physical size and a bit of complexity isn't an issue, then the use of a Tapped Horn, or even the BIB variety, is probably the "Ultimate" in performance.

For those who are realitively new to speaker design, I might add that GM is one of the very top, if not "the top" designer, of high performance speakers and his opinions should be seriously considered.
He is a recent member of AK, but his contributions to speaker design span a number of decades.

Best Regards,
Terry

 

[TerryO]

Terry, your concern with bandpass is that it hides a lot of the beautiful bondo. It's time to come to terms with this...

Busted!

Mr. Newman,

For your information, I prefer the term "APTS" (Activated Polyester Tone Sauce) to the rather generic usage of mere Bondo! While they certainly have an uncanny resemblance, the "subjective" intention of usage, renders a complete transmogrification of the inherent sonic properties of APTS.

While this may seem to be idle speculation on my part, I have consulted my Channeler; Kray Z. Knight, who has received independent affirmation from "Lester" the 50,000 year old Audiophile.

Best Regards,
Terry

 

[Altec Best]

For those who are realitively new to speaker design, I might add that GM is one of the very top, if not "the top" designer, of high performance speakers and his opinions should be seriously considered.
He is a recent member of AK, but his contributions to speaker design span a number of decades.

Best Regards,
Terry

+1 As far as I'm concerned Greg is ""THE MAN" Can you tell how grateful I am ? :yes:

And is the very best in the land or world for that matter ! :yes: :thmbsp:

And I have been fortunate enough to have his help and generosity with my project which is nearing completion ! I can't wait ! Thank You Greg !

 

[dumptruck]

I don't think sealed with boost is an option - excursion would spoil that, looks like.

It looks doable with a slot port and a box around 0.8-1.1 ft³. If you use a slot that uses box walls as 3/4 of its walls, i.e. a single piece of wood along one side, you get an end correction factor of around k=2.227, which shortens to length a lot and makes it manageable. Of course, hitting the tuning freq. you want could be a bitch.

Or, you could just build a box and stick 4' or so of shipping tube on top . Mini El Pipe-o?

 

[theophile]

I also am stoked to see GM posting here. :thmbsp: