OK, now my ears just perked up a little bit more (since I have a unused pair of Seas CA18RNX in "inventory". Do tell.
Thanks Paul!
That looks nice!
But the cabinets would look rather unusual if the internal dimensions would be 60x10x7?
Cbarth
It's a tall box. Unless folded, obviously. Tall cabinets are not especially unusual in high-end audio. And technically since the transition between a reflex (where the internal resonance employed is Helmholtz, and assumes a uniform internal air-particle density & no Eigenmodes) and an MLTL occurs at the point where the standing waves generated alter the acoustic alignment away from what is assumed under Helmholtz assumptions, you need one dimension of the box to be significantly stretched relative to the others for a design with little 'forcing' (i.e. without requiring a duct with a heavily restricted CSA and / or extended duct length). Assuming a typical 8in midbass, where it's likely to be tuned < 40Hz, that means you'll need at least a 4ft pipe length.
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It is not a published design I belive. I just saw a speaker on the net and I tracked down the builder. He told me it was Paul K. that had modeled the ML-TL cabinets.
This was for a single woofer, and I asked Paul if I could double the cross-section and add a second woofer.
I don't know if this is ideal, but I don't think I have heard a double 6,5 speaker with such an amount of bass. I have the ports on the back of the speakers and I have to drag them far out from the walls not to overpower the room. If I did it again, I would put the port's on the front.
These I have in my secondary system, but they sound so good I tend to listen to them the most.
Cbarth
You would fold the line once which means you could put it into the bottom, sealed off section of the cabinet having an internal height of ~30". Just out of curiosity I tweaked the model some more using a 72" line length and some changes in the locations of woofer and port. This caused the 1/4-wavelength resonant frequency from the line's length to be lowered from ~56 Hz to ~47 Hz, thus contributing to more of the system's tuning. That, then, allowed a 3"-diameter port to be only 4.75" long with lower peak air velocity and have adequate internal clearance. This longer line could also be folded once and fit into an internal height of ~36".
Paul
Paul
Thanks Paul!
That looks nice!
But the cabinets would look rather unusual if the internal dimensions would be 60x10x7?
Cbarth
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I've modeled so many TLs for others that I can't remember all of them or who I modeled them for, and I don't always have hard-copy records of the design, only email exchanges usually. So, I don't recall the original 1-driver design you discovered or communications with you for a 2-driver version! I'd appreciate you refreshing my memory.
Paul
I'd appreciate you refreshing my memory.Paul
It is not a published design I belive. I just saw a speaker on the net and I tracked down the builder. He told me it was Paul K. that had modeled the ML-TL cabinets.
This was for a single woofer, and I asked Paul if I could double the cross-section and add a second woofer.
I don't know if this is ideal, but I don't think I have heard a double 6,5 speaker with such an amount of bass. I have the ports on the back of the speakers and I have to drag them far out from the walls not to overpower the room. If I did it again, I would put the port's on the front.
These I have in my secondary system, but they sound so good I tend to listen to them the most.
Cbarth
Okay, the Pete Myers design. That's been quite a long time since I did that design.
For both the 60" or 72", single-fold ML-TLs I described, the lines' depths were 7". So, the dividers would both have to be 7" shorter than the internal heights of the two cavities; 23" for the 60" line, and 29" for the 72" line.
Paul
For both the 60" or 72", single-fold ML-TLs I described, the lines' depths were 7". So, the dividers would both have to be 7" shorter than the internal heights of the two cavities; 23" for the 60" line, and 29" for the 72" line.
Paul
A separate section above that for the woofer's TL could house a mid and a tweeter. Is that what you're asking?
Paul
Paul
Ok, finally I get it!
That would be reasonably managable cabinets.
If I was to put a midrange driver with a small compartment, like a short 4inch tube in the top of the cabinets, would that ok?
Cbarth
Yes, perhaps that is the best solution, separate mid/ tweet cabinets, and not put anything in the path of mltl.
But out of curiosity, compared to my dual Seas CA18RNX which is a known quantity for me, what would the gain /loss be?
The Seas CA18RNX mltl is aprox 43x7,5x19,5 internally, with dual 3x4,5 ports centered 3 inch above the bortom.
I'm sorry for all these questions, I know a lot of you guys put down many hours answering and modeling for guys like me (who don't have a clue ).
I really appriciate it.
Cbarth
But out of curiosity, compared to my dual Seas CA18RNX which is a known quantity for me, what would the gain /loss be?
The Seas CA18RNX mltl is aprox 43x7,5x19,5 internally, with dual 3x4,5 ports centered 3 inch above the bortom.
I'm sorry for all these questions, I know a lot of you guys put down many hours answering and modeling for guys like me (who don't have a clue ).
I really appriciate it.
Cbarth
You need not worry about putting other drivers, etc, in the path of the MLTL as long as those intrusions don't detrimentally affect the performance and are accounted for in the TL modeling.
Would there be any benefit from having a single SB23 in an MLTL compared to 2 of the CA18RNX drivers in an MLTL? Probably not. The SB23 has a larger Xmax I believe but the total Sd of the pair of CA18s is larger, and the paralleled pair of CA18s will have a greater sensitivity but a lower impedance.
Would there be any benefit from having a single SB23 in an MLTL compared to 2 of the CA18RNX drivers in an MLTL? Probably not. The SB23 has a larger Xmax I believe but the total Sd of the pair of CA18s is larger, and the paralleled pair of CA18s will have a greater sensitivity but a lower impedance.
No I'm sorry, you have to ask Troels /Jantzen about that...
It's their design/property...
Cbarth
Ha ha, good question!
Since it was me who started this thread, maybe I should answer.
When I built the new mltl cabs for my Seas speakers I was amazed by the quality and amount of bass.
These were in my secondary system.
But I have a lot on my plate at the moment.
I built some mini karlsonators with some Dayton ND90, that didn't turn out to well.
I have a pair of Alpair 12, that I'm trying out.
And I pulled out some Vifa C20 WJ from a pair of old Dali's that I am experimenting with.
And these old Vifa's have some of the midrange I have experienced.
I have on order some Seos 8 waveguides for dome tweeters that I will experiment with.
At the same time I really would like a set of mid sized, high quality speakers for my main system.
Not an easy task.
Maybe if the Vifa/waveguide combo turns out well, I go all in and build a dual SB23 mltl as bottoms for a really large 3 Way...
My wife will not be happy, but maybe that is the only way to go?
Since it was me who started this thread, maybe I should answer.
When I built the new mltl cabs for my Seas speakers I was amazed by the quality and amount of bass.
These were in my secondary system.
But I have a lot on my plate at the moment.
I built some mini karlsonators with some Dayton ND90, that didn't turn out to well.
I have a pair of Alpair 12, that I'm trying out.
And I pulled out some Vifa C20 WJ from a pair of old Dali's that I am experimenting with.
And these old Vifa's have some of the midrange I have experienced.
I have on order some Seos 8 waveguides for dome tweeters that I will experiment with.
At the same time I really would like a set of mid sized, high quality speakers for my main system.
Not an easy task.
Maybe if the Vifa/waveguide combo turns out well, I go all in and build a dual SB23 mltl as bottoms for a really large 3 Way...
My wife will not be happy, but maybe that is the only way to go?
Troels answer:
Hello Felipe,
Sorry, as you can see from the article, crossover values only come with the kit from Jantzen Audio
best regards
Troels
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