Just bougth 4 pcs JBL 2226J drivers and have some nasty visions of a pair of rather large dual 15" 3 way towers for stereo and HT use.
What route will YOU suggest i should follow?
and what drivers do YOU suggest i should use for mid`s and high`s
Simulations of the 2226`s suggests 10cuft ported to 40hz for a pair,
This is also what JBL recommends.
I have considered a WMTMW construction with JBL 2118J`s (if i can get my hands on 2 pairs) mated with a Beyma TPL150 or TPL150H.
If i go with this route should i follow JBL and go with sealed chambers of 0,25cuft for each 2118 and a 6db/oct filter at 700hz?
Maybe even the AMT can be used with 6db/oct xo if i cut them over at 2000+++ hz?
The cabinet itself are considered done in 30mm Baltic Birch, since its aviable locally (i migth even get it trougth my job)
Ps i know that i cant expect 20hz extension from these 15", so please leave that one alone 😉
What route will YOU suggest i should follow?
and what drivers do YOU suggest i should use for mid`s and high`s
Simulations of the 2226`s suggests 10cuft ported to 40hz for a pair,
This is also what JBL recommends.
I have considered a WMTMW construction with JBL 2118J`s (if i can get my hands on 2 pairs) mated with a Beyma TPL150 or TPL150H.
If i go with this route should i follow JBL and go with sealed chambers of 0,25cuft for each 2118 and a 6db/oct filter at 700hz?
Maybe even the AMT can be used with 6db/oct xo if i cut them over at 2000+++ hz?
The cabinet itself are considered done in 30mm Baltic Birch, since its aviable locally (i migth even get it trougth my job)
Ps i know that i cant expect 20hz extension from these 15", so please leave that one alone 😉
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I bought a quad of these myself when JBL blew them out in a tent sale packaged as 4648s @ $200 shipped, if memory serves.
My temptation would be to use them the way JBL does in their newest flagship, which is a 3.5 way where both woofers work together up to roughly 100 Hz, at which point one of them is low-passed. The remaining woofer is crossed to a horn @ 500-800 Hz and a super-tweeter takes over above 5000 Hz or so. A good CD horn like an EV HR9040 could be used to good effect here, and might not even need a tweeter if you can eq it properly.
My temptation would be to use them the way JBL does in their newest flagship, which is a 3.5 way where both woofers work together up to roughly 100 Hz, at which point one of them is low-passed. The remaining woofer is crossed to a horn @ 500-800 Hz and a super-tweeter takes over above 5000 Hz or so. A good CD horn like an EV HR9040 could be used to good effect here, and might not even need a tweeter if you can eq it properly.
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Seems like the drivers in your pic have a rubber, foam or butyl surround.
If thats the case they do probably also have a lover fs, and lower sensitivity.
probably not a 2226
I do also belive that the upper edge of the midrange horn would cause a lot of disturbance for the sound radiation from the supertweeter unless its extremely narrowly radiating in the vertical plane.
These speakers are probably made for people with living rooms far larger than mine, after all, flagship speakers are mostly made for extremely wealthy people with very large living rooms, sadly enough, i am not one of them, i am just a poor lonesome adiophile cowboy (without the cows, luckily enough) 😉
Hi FE3T,
If you construct a WMTMW it would be best to keep the woofer ports away from the tweeter-midrange to avoid dips at frequency wavelengths that hit the ports. There are a few diyAudio MTMs which have measurements showing these ripples, and new designs that move the ports to the far box corners.
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Drew Daniels was one of the highest regarded engineers at Altec Lansing and JBL. His home speakers used a horn loaded compression driver tweeter that mated to a 10" cone midrange and two 15" woofers in a BR cabinet. Here are his comments.
"THE MAGIC HORN FIX
There are some tricks that are essential for eliminating horn "honk." The first is to use the cone driver placed just below the horn, all the way up to a frequency where it begins to "beam" due to the relationship of sound wavelength and cone diameter. At a frequency where the resulting Q-factor (directivity) of the cone matches that of the horn, the transition from cone to horn will be smooth, and not abrupt-as it can be in systems where the cone is too large and the horn is too small. If this condition is met, and the frequency response of the cone is good well beyond the frequency up to which it is used (a well-behaved upper end rolloff), then the horn will enjoy a seamless transition from the cone and will not honk, assuming its frequency response is good and uniform over its output angle. This latter condition is referred to as being "power-flat" and is very important to the transparent operation of the speaker system in rooms, with their concomitant acoustic implications. If the speaker system is power flat, the sound in the room will be as good as that particular room will allow it to be.
THE MIDRANGE
The midrange driver must be a cone, unless you live in a theater and don't mind a 4-foot high horn (I crossed my mid at 300 Hz into the woofers). As it turns out a mid cone supplying 300 Hz to 1200 Hz gives the proper effortlessness with very little power, and thus has extremely small cone excursions and low distortion. As I mentioned earlier, I had to trim the 2012H mid cone back 10 dB on the amp's gain control to get the response through the band flat. The power absorbed by the mid cone driver amounts to milliwatts most of the time, which helps to hold harmonic distortion to very low levels, typically well below 1% THD up to dangerously loud volume.
I experimented with a dozen midrange drivers before I was confident that the 2012H with its high efficiency and limited excursion linearity would produce sufficiently low distortion. It is a wonderfully transparent driver and a large part of the reason this speaker system sounds like listening to live music rather than loudspeakers. (the AES Lambda TD10M or TD10LO are excellent alternatives)
The driver is mounted on the baffle as close to the horn as I could get it with my inexpensive mid chamber geometry. You could do better if you are willing to cut the shape of the mid driver's frame into the lower lip of the horn and snug the mid frame up into the cutout and, of course, figure out a mid chamber arrangement that would clear the horn and driver behind the baffle, but this is not measurably better than just a touching fit.
The enclosure for the mid cone consists of a 10-inch diameter concrete casting tube made of plasticized paper. Such tubes are made by Burke Tube and Sonotube and no doubt many other regional paper products manufacturers. The tube is mounted to the baffle by gluing into a counter-bored shoulder cut-out, routed in the back of the baffle around the mounting hole. The tube is about 12 inches long (deep), it is filled completely but loosely with a "jelly roll" of unbacked fiberglass house insulation cut from a roll about 4 feet long. The back end of the tube is sealed air-tight with a disc of 1-inch thick medium density fiber board-the same material used to build the rest of the box."
If you construct a WMTMW it would be best to keep the woofer ports away from the tweeter-midrange to avoid dips at frequency wavelengths that hit the ports. There are a few diyAudio MTMs which have measurements showing these ripples, and new designs that move the ports to the far box corners.
=========
Drew Daniels was one of the highest regarded engineers at Altec Lansing and JBL. His home speakers used a horn loaded compression driver tweeter that mated to a 10" cone midrange and two 15" woofers in a BR cabinet. Here are his comments.
"THE MAGIC HORN FIX
There are some tricks that are essential for eliminating horn "honk." The first is to use the cone driver placed just below the horn, all the way up to a frequency where it begins to "beam" due to the relationship of sound wavelength and cone diameter. At a frequency where the resulting Q-factor (directivity) of the cone matches that of the horn, the transition from cone to horn will be smooth, and not abrupt-as it can be in systems where the cone is too large and the horn is too small. If this condition is met, and the frequency response of the cone is good well beyond the frequency up to which it is used (a well-behaved upper end rolloff), then the horn will enjoy a seamless transition from the cone and will not honk, assuming its frequency response is good and uniform over its output angle. This latter condition is referred to as being "power-flat" and is very important to the transparent operation of the speaker system in rooms, with their concomitant acoustic implications. If the speaker system is power flat, the sound in the room will be as good as that particular room will allow it to be.
THE MIDRANGE
The midrange driver must be a cone, unless you live in a theater and don't mind a 4-foot high horn (I crossed my mid at 300 Hz into the woofers). As it turns out a mid cone supplying 300 Hz to 1200 Hz gives the proper effortlessness with very little power, and thus has extremely small cone excursions and low distortion. As I mentioned earlier, I had to trim the 2012H mid cone back 10 dB on the amp's gain control to get the response through the band flat. The power absorbed by the mid cone driver amounts to milliwatts most of the time, which helps to hold harmonic distortion to very low levels, typically well below 1% THD up to dangerously loud volume.
I experimented with a dozen midrange drivers before I was confident that the 2012H with its high efficiency and limited excursion linearity would produce sufficiently low distortion. It is a wonderfully transparent driver and a large part of the reason this speaker system sounds like listening to live music rather than loudspeakers. (the AES Lambda TD10M or TD10LO are excellent alternatives)
The driver is mounted on the baffle as close to the horn as I could get it with my inexpensive mid chamber geometry. You could do better if you are willing to cut the shape of the mid driver's frame into the lower lip of the horn and snug the mid frame up into the cutout and, of course, figure out a mid chamber arrangement that would clear the horn and driver behind the baffle, but this is not measurably better than just a touching fit.
The enclosure for the mid cone consists of a 10-inch diameter concrete casting tube made of plasticized paper. Such tubes are made by Burke Tube and Sonotube and no doubt many other regional paper products manufacturers. The tube is mounted to the baffle by gluing into a counter-bored shoulder cut-out, routed in the back of the baffle around the mounting hole. The tube is about 12 inches long (deep), it is filled completely but loosely with a "jelly roll" of unbacked fiberglass house insulation cut from a roll about 4 feet long. The back end of the tube is sealed air-tight with a disc of 1-inch thick medium density fiber board-the same material used to build the rest of the box."
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Sorry, but I didn't mean to imply that the woofers were the same as used in the 66000, just that the topology could be a good one for your 2226s.
If you go with a WMTMW or WTW layout, you are going to have challenging crossover decisions and compromises to make if you want to avoid big time lobing and listening axis issues. What kind of measurements are you able to make and what crossovers/loudspeaker dsp do you intend to use?
If you go with a WMTMW or WTW layout, you are going to have challenging crossover decisions and compromises to make if you want to avoid big time lobing and listening axis issues. What kind of measurements are you able to make and what crossovers/loudspeaker dsp do you intend to use?
FE, what you are proposing is very similar to what my pwn project started out as several years ago, but I have 2225 instead of the 2226 with 2123 (as per Daniels) and a CD/WG instead of the AMT as it wasn't available then and too expensive for my budget now.
There are plenty of alternate mid drivers apart from the 2118, especially from the Euro manufacturers, from the 10NDA610 to the 6MD38 as the first ones to cross my mind.
Two suggestions would be that if enclosure volume is an issue and you have no objections to EQ, a pair in about 120L, tuned to 40hz, 6th order is an option.
I also don't like ports adjacent to mids so I'd put them elsewhere. like on the bottom or rear. Dantheman has shown the diffraction effects of ports on the front baffle with his Behringer measurements.
There are plenty of alternate mid drivers apart from the 2118, especially from the Euro manufacturers, from the 10NDA610 to the 6MD38 as the first ones to cross my mind.
Two suggestions would be that if enclosure volume is an issue and you have no objections to EQ, a pair in about 120L, tuned to 40hz, 6th order is an option.
I also don't like ports adjacent to mids so I'd put them elsewhere. like on the bottom or rear. Dantheman has shown the diffraction effects of ports on the front baffle with his Behringer measurements.
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