| OTMOPO3OK |
Hello,
i've recently acquired Lambda Acoustics PB12-PL Sub with Copper Faraday Rings which greatly decreases distortion and inductance. So i tried it in open space and i liked it...well maybe just a little bit boomy BUT since it's gonna be used not only for music but for HT as well i guess i have to compromise.
I would like to know which cab would you recommend for more live feeling to it. So maybe ML TL or something else. I am afraid if i put it into BR it's gonna be even boomier (or maybe not). If you can model some dimensions for me that would be very helpful. BR,ML TL i can model myself as long as you suggest some tricks for me to get the sound i want. Anything else like horns, etc. which i'm not familiar with, i need you to model that. I want clean fast bass mainly for music. I don't care about HT since just about everything that BOOMs works for it. :) Another thing i noticed that even when i cross the sub at 80Hz i can localize it, so maybe some tips how to reduce that either with enclosure or placement.
Anything up to 3-4cu.ft. is fine with me and i'd like it to go at least as low as 20Hz.
Here are the specs.
Fs 21.0 Hz
Qms 4.2
Qes 0.32
Qts 0.30
Vas 160 Liters
Cms 0.4 mm/N
Mms 143 grams
Sd 530 cm2
Rms 4.5 Kg/S
Bl 14.4 N/A
Re 3.5 ohms
Z 4ohms
Le 0.3 mH
Pe (nom) 300 Watts
"no" 0.44 %
1WSpl 88.6 dB
Xmax 14 mm (peak)
Xmech 20 mm (peak)
Vd 0.742 Liters
Thank you very much for the effort !!!
I promise to post some pics once i'm done! :)
PS. that's the one and only woofer i got with my last money (college student) so please don't suggest to get second one for something like dipoles. :D |
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| OTMOPO3OK |
OK i'll start..... here is the ML TL i modeled (Thanks to MJK) which is ~80" high so it fits thru my doors :)
I tried making it more narrow but the graph looks wiered so i settled on ID 13"x13"75" which OD are 16"x16"x80" and 4" x 7" Port. I left stuffing at it's default setting 0.25, i probably can use more since it's a sub after all.
Is it safe (for the driver) to tune it lower?
BTW can 1/2" HardiBacker (cement ceramic board that goes under the tiles) be used on the walls of the subwoofer inside? Maybe even instead of the second layer of plywood or to complement it? Or is it going to come undone and rattle? I haven't dealt with the stuff.
Any other suggestions? |
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| Cloth Ears |
Hi OTMOPO3OK,
This is probably not what you're looking for, but I run a pair of these as my woofer boxes. They're sealed, and have an F3 of around 53Hz (possibly not what you're looking for) - but they're 10dB down at 26Hz, and 20dB down at 14Hz. They can play all day at 110dB (OK, for an hour, while the neighbours were all out and I locked myself in the bedroom). As the listening room is not all that big, I don't actually use a subwoofer, as low organ notes and atomic explosions cause all the windows to rattle too much with only these babies.
I have them in a 54 litre (25mm) MDF box (bigger, but there's lots of bracing). There's a little bit of cheap sound foam on the back walls, but I didn't fill it up that much, as there's about 20 3-inch holes through the bracing which is enough to diffuse a lot of the sound wave in the box. The modelling says that I shouldn't be getting more than 12.5mm of excursion (at the levels I mentioned above) - and that's at 10Hz, which could be attenuated if I used a rumble filter.
A hefty amplifier is probably going to be your major problem. Any number of SS amps can produce 150w, it producing them cleanly and with control that is the problem with this speaker IMHO. Only one of the amps I have on hand (an old Denon which weighs a ton) seems to be capable of driving these. I'm now looking for another one of these (second hand) as I'm not capable of building my own...yet. |
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| OTMOPO3OK |
Hmm, interesting... you went for a sealed cab with drivers designed for ported enclosure. 54Hz seems a little high but 110dB is nice although i don't need them to play that loud (which they will probably anyway). It's nice to know someone still uses these drivers.
My main goal is to make sure the sound responce is fast and not boomy.....and also integrate them into my SMALL appartment. I have a place in the corner (for that MLTL) or next to my PC desk 27"x18"x18" ID (~ 4 cu.ft. BR) i have actually up to 40" next to my desk. I could even make a BR or ML TL box 11"x35"x70" ID and lay my mattress on it (which serves me as a couch too).
My Sub is My Bed !!! kinda thing....:bigeyes:I'm modeling it right now...:)
I bet it's nice to put 15Hz sine wave thru it and enjoy relaxing massage. :D
BTW my amp is 350W @ 4ohms Rythmik Audio. Very nice unit. I made an enclosure for it and it sits in my flexy-rack. I don't believe in running interconnects for 30ft to the sub. I'd rather run speaker wire. Way better results.
Keep them coming.. I would really like to hear benefits and shortcommings of horns and maybe having a design, since i have room under my bed and could put it there. |
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| Cloth Ears |
On the design, I cheated a little. I also modelled the same sized box with an (external) port tuned to 28Hz and built a flimsy box (particle board) to test it. I tested the sealed version by simply stuffing the port (19mm cardboard tube) with a few windcheaters.
The model of the ported version had a -3dB point of about 30Hz (I think) and then rolled off much more quickly. I think -10dB was about the same as the sealed version, and at 16Hz was about 8dB lower than the sealed version. Also, I didn't test it to the same levels, as the model indicated that I'd be getting some really wild cone excursion below about 25Hz (where some of my music is played).
Subjectively, there was a fair amount of boom at around 30Hz from the ported version (probably because my room is fairly small - 6x4x2.5m). The sealed version played well on everything all the way down and there was no boominess. They also matched well with the lower end of my Elac speakers.
On another note, I'm very interested in what you think of the Rythmik. It has a bit of a rumble filter that I'd be interested in if I was to build a subwoofer with the 2x15 inch Lambdas that I still have lying around. You would probably be able to use the 20Hz/mid setting to avoid excursion during low/loud playing if you decided to go the ported version. I'm not sure what the cone excursion is for the transmission line model you provided.
Good luck... P.S. the TL is more likely abot to provide a bed-base (and massage table) than either the sealed or ported versions for this speaker. |
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| gjo |
Hi
I got one of these and used it with a 15inch PR. Initially I used a single PR in a small (45-50 lt box) and then have migrated last week into an 85 lt dual 15 inch PR box, which I am evaulating now. Check stryke.com for various alignments. I strongly recommend the PR option it sounds quite different(better) from my earlier Audio Concepts 12 inch sealed box sub.
I also have one of the Lambda 12 inch LE series sealed box (SB) drivers but I dont plan to use that for now. The PL series drivers , are ,in my view among the best sub drivers made in recent years. Amps are plate amps from stryke audio.
If you need any suggestions about PR alignments,just ask!
George |
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| Cloth Ears |
Hi gjo,
What PRs did you use with the PL? |
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| OTMOPO3OK |
Jont and George thanks for all the suggestions.
WoW you are really pushing me to build a flimsy test cab:D. I was trying to avoid it but i would like to get my design as "pefect" as i can so i guess i'm gonna have to make a prototype. You never know how it turns out,huh...The room gain really helped your sealed sub to integrate better. I have a big mode at 50Hz in my room and that's what booms the most, then 118hz, etc. :hot:
As far as Rythmik amp goes (yes it's the one from Stryke as well as woofer) it does have a nice filter. i tried it on my DIY sub with Pioneer 15" driver and when u switch between settings you can see the driver move half the distance, you can hear it too of course..the sound is more damp. It's a nice reasurance especially when your design reqires you to control the driver's excursion.
George,
On the note of PRs. I was thinking of doing a PR design (mainly because of the simbios of sealed and ported advantages it offers and size considerations but just never got the money to buy 2 PRs. I heard that one is not worth it, but for the price of two PRs i could get another driver and i decided to stay away from it untill i get richer. It's definately on my list of experiments thou. I talked to John (of AE) and he told me great things about PL motor and faraday rings. This driver should be better sounding than the LE version. It's a shame a high-end subwoofer manufacturer (well, if you can call one person that :D) had to sell his business. Let's hope John keeps it up. Thanks for the support.
In the meanwhile I'm going to have to learn how to model regular folded TL or tapered folded TL to make the cabinet smaller but still stick with TL design. For some reason I feel like i did enough BR boxes already..:bawling:
Thank you again. |
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