Seas L18RNX/P in an MTM configuration?

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Dave Bullet

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Joined 2002
Although not an MTM, Zaph designed (although never built and tested) a TMM with the Seas 27TBFCG tweeter and 2 L18 woofers here:

http://www.diyaudio.com/forums/showthread.php?postid=1077540#post1077540

Just checked - and Zaph's link to his site is broken. I do have the crossover so if Zaph doesn't mind I can post here for you.

I siulated a TMM (same thread as above here:

http://www.diyaudio.com/forums/showthread.php?postid=1106315#post1106315

The problem with the design I did is I believe the 0.5 woofer is playing too much into the midrange (full 1.0 woofer space) which will adversely affect the sound (ie. midrange will be "smeared" for want of a better word).

I'm currently working on a 3 way with an L26, L18 and 27TBFCG.

Let us know how you go / what decisions you make. I too like the look of the Seas L series drivers. The L26 also tested out well on Mark K's site

Hope the above helps,
Dave.
 
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kyselym

Member
Joined 2006
Can you elaborate?
Click to expand...
me? elaborate what? why L15 will do it better or about MTM using L18? either I don't think my english is as good to be able to well explain why...

Do you know that L18 has to be crossed realy low? around 1.6-1.8Khz to achieve very good results?(as steep as possible) L15 will be fine with 2-2.25Khz. You will have problems to find suitable tweeter for a pair of L18 to handle such low crossover point at high power levels. There are more problems...and you will have to measure not only simulate.

Only thing I can do for you is, I wil give you construction plans, measurements and crossover design for speakers I'm going to build. It will use 27tbfcg tweeter L15 as midrange and pair of L22rn4xp in closed box. It will take around 1 year till it will be finished and there is a option that I will not suceed to cross it well and will have to use one L26 instead. But I don't think you want to wait so long. so my advice is to find some 3way design using theese seas L drivers and build it insted of designin own MTM with L18.

example:
http://www.rjbaudio.com/AlpheusMkII/alpheusmkii.html (try to ask RJB for older version taht uses L12)
or if you insist on MTM: http://www.hardwareanalysis.com/action/printarticle/1815/

or build zaph's:
http://www.zaphaudio.com/audio-speaker12.html
and support them with two small subs with L26 or L22 with active crossover if the bass will not be enough.
or just build zaphs L18 design with one L18 and instead of using second L18 as 0.5 woofer use bigger like L22 with appropriate pasive crossover(not as good idea as you might think but you can go active later)

so many ideas... :)
 
M

Mor den Siur

Member
Joined 2007
Re: Re: Seas L18RNX/P in an MTM configuration?

or build zaph's:
http://www.zaphaudio.com/audio-speaker12.html
and support them with two small subs with L26 or L22 with active crossover if the bass will not be enough.
or just build zaphs L18 design with one L18 and instead of using second L18 as 0.5 woofer use bigger like L22 with appropriate pasive crossover(not as good idea as you might think but you can go active later)

so many ideas... :) [/B][/QUOTE]




Hello

Is there anybody who tried using Zaphs L18 design with L22 in 2,5 way passive crossover??
Like in:
http://www.highfidelity.pl/artykuly/0612/marcus.html
 
D

Dave Bullet

Member
Joined 2002
GOWA,

In the link I provided, Zaph explains why he wasn't happy with the TMM 2.5 way he designed. Here is the link directly to his post:

http://www.diyaudio.com/forums/showthread.php?postid=1077540#post1077540

Zaph tries to simplify his crossovers for cost and complexity reasons (unless the quality of the drivers justifies a more complex than usual crossover - ie. his ZD5 speaker). Either he wasn't happy with the complex crossover for a TMM 2.5 way based on the L18, or moved onto a more interesting project, who knows.

David.
 
D

Dave Bullet

Member
Joined 2002
I wouldn't bother adding an 8" driver (L22) to an existing 7" driver design. You may as well go for the L26 or bigger (ie. a Dayton 12" RS series or similar). The 7" should easily go down to 80Hz in any configuration (sealed / vented) using the much larger driver to sweep the volume required for the bottom octaves.

With a 12" below 80Hz - you will definitely want to go active to the L18.

I don't think anyone has a design for an L22/L18 combo - this tells me there is no point. Either go a for a midrange with the L22, or a much larger (ie. 12") driver for the L18.

David.
 
K

kyselym

Member
Joined 2006
I tried to add 0.5 woofer (L26RFXP) to L18 (design by Tonny Gee DD8mkII) and without proper measurement it doesn't sound well. At the begining I liked that low bass but for some time(few months) I found out that if I disconnect L26 it sounds much better! well low bass is lost but overall sound is much better. So here is the point: without measurement and proper crossover(which can't be made without it) it is bad idea. Biggest problem is getting drivers in phase.

but as I have drivers and boxes at home I may design you a crossover for L26rfxp or L22rn4xp when I have some time. But no promise here as I'm very busy this time.

as I mentioned earlier, copy some well made 3way design, you will be much happier with it. ;)
 
M

Mor den Siur

Member
Joined 2007
Thanks
I think that L22 could add "something":) in bas ( Fs=23 Hz as I remember) more than another L18.

I decided to built Zaph L18 without any changes. Now my listening room has 14m2, and is too small for, let's say "big bas". If I weren't be satisfied, I would make some steps to change it ( read L22 or L26, but wit measurements). I think it is the best idea, also with economical aspects. There is huge difference in price between L22, L26 and Zaph's L18 without that speakers:)

kyselym - If there were possibility to make XO for 1)L22 and 2)L26 I would be gratefull. I won't make such project in following few months, so don't hurry:)
It could be point to start with, when I would start adding bas section to L18. I think that some other people could be happy also:)
 
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