"Best" PA subdesign for the Eminence Kappalite 3015LF

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Hello everyone!

First post for me on this forum, but I have been lurking for a while, reading about a lot of interesting sub designs here:)

As the title says, I´m wondering which design you guys would say is the best for the Eminence Kappalite 3015LF driver.

To give you some background, I´ve built two BFM Titan48´s, 80cm wide, loaded with one 3015LF each, and I have 2 more drivers waiting for cabs.

I´m not really unhappy with the T48, but they are large, and sometimes I´d really like to go a bit lower than 40hz. I probably should have built something like like Bills T60 from the beginning, but I didnt..

I have a small rental company, so my PA need to be able to handle most kinds of music as we do both Livesound and a lot of electronic dance music events, with EDM being our forte. Both indoors and outdoors, but mostly indoors so far.
What I want is a cab that can either go lower than a quad of T48s (steep HPF @35hz) with a flatter response curve and similar size or smaller. Atleast 30hz with reasonable SPL.
Or, a smaller cab that does the same frequencys as the T48, 35/40-100hz, but is smaller and flatter response.
I would trade SPL at 100hz for more SPL at 35-40hz.
The T48 is not very flat from 35 to 100, so I usually EQ them a bit flatter.

I must say that I love the nice clean effortless bass they give, on Livesound they are fantastic, but then you dont need sub 40hz.
But I feel they are lacking when we are playing stuff like Hardstyle or Hardcore, some Psytrance or even some modern House music.

I ran a bunch of songs through Resonic Alphas RTA, and most electronic dance music that I have/play seem to peak at around 27-32Hz..

Also, I might still be missing the distortion/harmonics that "normal" 2x18cabs and such produces, but the FLH doesnt..
I´ve read around here that a Tapped Horn seems to have more distortion then a Front Loaded Horn, so perhaps a bass reflex or TH would suit my music better?

Specifically the Hardcore music I listen to is almost based on distortion, so perhaps the horns are actually taking away something that should be there?

Of course, the sensitivity still needs to be high, I do need a lot of SPL :p But I no longer sure that Bills T48 actually gives you all that much more sensitivity if one wants a lot of low bass, or simply EQing it flat.

I´ve read some threads about designs like THAM15 and similar, and I´m intriuged by these rather simple to build designs and their flat responsecurves :)

So, what would you guys recommend?

PS, I have 4 sheets of baltic birch, 12x1220x2440mm waiting to be used, and I´d like to build atleast two more subs in the nearest weeks:)

Best Regards
Robin Larsson
 
As the title says, I´m wondering which design you guys would say is the best for the Eminence Kappalite 3015LF driver.

What I want is a cab that can either go lower than a quad of T48s (steep HPF @35hz) with a flatter response curve and similar size or smaller. Atleast 30hz with reasonable SPL.
Or, a smaller cab that does the same frequencys as the T48, 35/40-100hz, but is smaller and flatter response.
I would trade SPL at 100hz for more SPL at 35-40hz.

Also, I might still be missing the distortion/harmonics that "normal" 2x18cabs and such produces, but the FLH doesnt..
I´ve read around here that a Tapped Horn seems to have more distortion then a Front Loaded Horn, so perhaps a bass reflex or TH would suit my music better?

Specifically the Hardcore music I listen to is almost based on distortion, so perhaps the horns are actually taking away something that should be there?
Robin,

Loud, sub 40 Hz response with low distortion are not easily satisfied when using a weak cone with relatively low Xmax (the 3015LF) in a horn.

Lots of musical styles have distorted bass, but it is not necessary to add cone breakup distortion on top of that, though distortion makes a sub seem louder.

If you don't mind distortion, there are several TH designs to choose from that use the 3015LF.

The larger they are, the lower and louder they go.
What size are you looking for?
 
Weltersys, thanks for your answer!

Yeah, I was kind of expecting something along those lines, that the 3015LF is a "weak" low xmax driver. Coming from the BFM forum where the 3015LF is highly regarded, it almost feels strange ;) But well, I did know there were better drivers out there;)

I get what you are saying, and I understand that there is no free lunches. But perhaps there is a better mousetrap for low bass and 2-4 3015LF´s then the Titan48?

Well, if I cant get really low bass with the 3015LF´s, say good 30hz or even slightly below, then I may consider building a quad of somewhat smaller cabs, 35-40hz HPF and use them primarily for livesound and smaller electronic gigs. And then find a better driver and design to go to 25hz or so for the more demanding electronic shows.
So size is a it dependant on how low I could practically go with the drivers I have on hand.

But a design that could go to atleast 30hz and relatively flat with just 2, could be allowed to be a bit bigger than the T48s, and the ones I have now are 61x80x122cm outside.
But, say that I go with a 35-40hz design, then I´d like them to be smaller, in that case size would be more important, say 50x60x100cm or smaller, or that range :)

Could you recommend any tapped horns using the 3015LF? :)

Are tapped horns "allways" more efficient than Bass reflex? for the same driver and similiar size and range?

Regarding distortion, well, as you say, it makes cab sound louder, but it doesnt sound as good of course, but there might be a better balance then a FLH?
I´ve been tought that FLH´s "filters" out distortion and harmonics that the driver creates, but if thats true, shouldnt it also filter out distortion that was put in the bass-sound by the artist? Or are those sounds actually higher in the frequencyrange and then played by the tops?

Thanks again Weltersys!
 
turbodawg, thanks for your input! I have to say that I´ve been thinking about bass reflex also. Would I have to give up very much sensitivity if I went with BR tuned to 30-35hz?

Are you saying that 30z wont happen with the kappalite 3015lf in a reasobly sized horn, or that no driver/horn could do it?

If I would go the BR route, would there be any real performance benefit of going 2x15 compared to two 1x15s? Singles will of course be more work to build, weigh a bit more, but be more flexible.

How low could I resonably go with a horn and the 3015? 35hz as the T48 is capable of? Wouldnt a tapped horn be smaller for the same output?
 
For the frequency and size you want I would consider a PPSL enclosure
http://www.diyaudio.com/forums/subwoofers/177905-thread-those-interested-ppsl-enclosures.html.
The PPSL double reflex design with with the drivers in a plenum chamber helps to reduce some harmonic distortions when compared with single driver boxes. Apart from an extra 2 panels of wood there is very little difference between a conventional double 15 reflex and 2 single driver cabinets.
Otherwise your goals are not that realistic, in as much as tuning that low will lose you lots of efficiency. Tuning the boxes higher will gain lots of efficiency.
You say you have 4 sheets of 12mm 8' x 4' birch ply - this is fairly thin for most reflex designs.
On the other hand you could build 4 SS 15 cabs with the timber - load them with your 3015 drivers and if you can live with the frequency response you would be in business.
http://www.diyaudio.com/forums/subwoofers/170771-single-sheet-th-challenge.html
This is probably your best option!
 
1)Could you recommend any tapped horns using the 3015LF? :)
2)Are tapped horns "allways" more efficient than Bass reflex? for the same driver and similiar size and range?
3)Regarding distortion, well, as you say, it makes cab sound louder, but it doesnt sound as good of course, but there might be a better balance then a FLH?
4)I´ve been tought that FLH´s "filters" out distortion and harmonics that the driver creates, but if thats true, shouldnt it also filter out distortion that was put in the bass-sound by the artist?
5)Or are those sounds actually higher in the frequencyrange and then played by the tops?
Robin,
1) Not for use below about 40 Hz. I tried the 4015LF (stiffer than a 3015LF) in my Keystone TH and it was so distorted I didn't even bother measuring the distortion, which was gross compared to Lab 12s or the B&C18SW115-4.
Those lightweight drivers can stand up to the pressures in BR, but if you try to get the extra 6 dB or so output a TH can offer, the extra output will have plenty of extra distortion.
2) If the driver works for the TH, yes, but the optimum TH will be slightly larger than a BR for a given low frequency corner.
For maximum output per given truck space, BR beats TH, but requires more power and drivers.
3) FLH do tend to filter harmonics better than TH, but don't require multiples for low bass. When using good drivers, distortion is not a problem in TH.
4,5) Harmonic distortion generated by loudspeakers are not part of the original signal, and are at multiples of the fundamental frequencies, ie, 40 Hz, second harmonic 80 Hz, third 120 Hz, fourth 160 Hz, etc.
Even order harmonics are always musically related (octaves), but odd order harmonics are not, and can sound weird, wrong and just plain lousy.

Push Pull reduces only even order harmonics.

If distortion is present in a recording, a clean system will reproduce the distortion as the producer intended it, upper harmonics from the top speakers.

Art
 
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yep I've built big and small on the 3015lf and variations. Best overall compromise is the SS15 (in my opinion) Highpass at 32hz 24db/oct LR.

T48 is -13db @40hz vs 100hz. (by design) A TH is a world apart in terms of it's response curve.

SS15 is vastly different than a BFM FLH.

(I know... the reason the T36 is no more on BFM's site is because of me.....)
 
turbodawg, thanks for your input! I have to say that I´ve been thinking about bass reflex also. Would I have to give up very much sensitivity if I went with BR tuned to 30-35hz?

Are you saying that 30z wont happen with the kappalite 3015lf in a reasobly sized horn, or that no driver/horn could do it?

If I would go the BR route, would there be any real performance benefit of going 2x15 compared to two 1x15s? Singles will of course be more work to build, weigh a bit more, but be more flexible.

How low could I resonably go with a horn and the 3015? 35hz as the T48 is capable of? Wouldnt a tapped horn be smaller for the same output?


Well, you can check out my 15" project here, they hit 30hz indoors and weigh 55lb built up and finished, 22x20x16 box, 1/2" plywood:

http://www.diyaudio.com/forums/subwoofers/219923-ultra-compact-ported-15-dayton-ref-ho.html

I'm extremely happy with the portability and performance of them so far, they seem to be somewhat efficient by the models, but who knows.

I had the kappa in horn resp, in a BR have to go up to about a 150l chamber to get any decent response down to 30hz, so about 6 cubes per driver for a cab, which is wildly ineffective, might as well keep the t48's.

Oh and yes, I would consider the T48 "big", not going to get anything smaller in a horn that will hit 30hz that I'm aware of.
 
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T48 is a 1/4 wave FLH without reactance annulling (by design)
An increase of 9 dB in power results in only a 3-5 dB increase in SPL, but around 7- 13 dB increase in distortion in the T48 test.
I wonder what they were loaded with?
 

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Here's a comparison of reflex vs TH for the 3015LF
The reflex cabs are 125 litre internal and tuned to be reasonably flat with a 46.5hz port tuning.
The SS15 cabs are about 210 litre internal.
Both are driven to Xmax at about 58V which is roughly in line with their 450W rating
The SS15 cabs are louder than the reflex from about 48Hz up in singles and about 42Hz in quads. It takes 6 of the reflex cabs to outperform the 4 SS15 cabs. The 6 reflex cabs would be still slightly smaller than the 4 tapped horns! but you would need 2 extra drivers and probably another amplifier to achieve this.
Build bigger reflex cabs and you might be able to get a lower frequency response but the cabs would be excursion limited.
There are no free lunches in speaker design but 4 SS15 cabs are within your grasp - You have the drivers and you have the timber.:D
Regards Xoc1
 

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Thank you very much for your input guys!
Great to hear about someone else building something nice with the 3015LF:)

After all suggestions here, I must say that I´m leaning very heavily towards the SS15 right now!

Turbodawg, thanks for simming the 3015LF in a BR cab, if I understood you correctly:) I agree, seems that it wouldnt be worth trying to go to 30hz with the 3015LF, either in BR or Horn.

So, it seems that the Kappalite 3015LF simply isnt the driver to use in a portable PA if I want to go down to 30hz, going bigger then my current T48s doesnt feel all that fun...
I´m thinking that it might be best to use the 3015´s in smaller cabs, optimised for 35 or more like 40hz, and then look at bigger subs that goes to atleast 25-30hz, preferably horns for the efficiency, using better and maybe bigger drivers than my current 3015s.
Those bigger subs would probably only be used for larger shows with electronic music that really can use the extension.
So there would still be a good spot in my inventory for something like 4-6 SS15´s :)

Xoc1, thanks for your comparison! It really does makes me want to go with some kind of Tapped Horn!

jbell, I´ve been reading as much as I could of your Single Sheet TH challenge thread, and I really like it! Havent read half of it yet! :p The only referenceses I´ve seen you make for the HPF for the SS15 has been a LR48 @ 40hz, but you wrote LR24 @ 32hz to me yesterday? A bit confused here :)

If I could get useable response down to 35-32hz with say 4 or even 6 SS15, well, then they are even more enticing:)

Seems that a lot of people think that the SS15 is the cab of choice for the 3015LF, but is there a design that could use the 3015LF, using a bit more wood(being larger) that would go say 5hz lower with a good response?
I´ve seen references to the Furysub, but all links to it have been dead:(
The THAM15 cant use the 3015LF, can it?

Jbell, I´m kinda noticing that your not a very big BFM/T48 fan, and it does seems like the SS15 has a better responsecurve than the T48 if one wants useable 40hz. You, or anyone else, dont happen to have chart that compare them? :) Or atleast, a chart for the SS15, havent found one.. :(

Sorry for the long post guys...

Thanks again for all your help!
 
T48 response

I looked at the Prosound Shootout 2007 mesurements that jbell linked to, I cant say they look good for the T48, compared to Bills posted responsecurve, atleast not for the 24" wide version.
It does of course also depend on which driver that was actually used in the cabs measured back in -07.

In all honesty, I have almost never been very impressed with the T48s I have, sure they do get loud, and clean, but its mostly upper bass frequencys, as to be expexted, and I´ve almost allways wanted more, more SPL and probably more extension as well when running EDM. For livesound they have been really good:)
At one rave that we ran sound for 2 months ago, we got some really good bass though, 2 cornerloaded T48s in a room that is about 7x12m, 2,7m ceilings, one sub in each corner of one short wall. The place was more or less coming apart :p
So far no-one has complained on the extension, or spl for that matter, it might be just me that wants more ;)

But I must say, the BFM Tuba30 impressed me alot when I ran my 2 DR280 tops with a friends 4 T30s, v-plated and wall-loaded, also on a smallish venue.
I´m thinking that much of what I´m missing with the T48 is the extension down to 30hz. But on the other hand, I´m probably not getting all that much 40-50hz bass with the T48s, so a design that gets more in that area might be a good way to get closer to what I want:)

I might just have to build 2 SS15s or similar to compare :) Seems to be more than a few people that have gone from T48s to SS15s and have been impressed!
 
If you follow some of the links from SingleSheet challenge post1, we did a bunch of analysis, and determined the optimum Highpass of 32hz, 24db/oct LR. I usually go 'safe' on the high pass which is where 40hz came from, but have actually become a believer in highpass a bit lower. It keeps the cone moving to cool the coil, but keeps things below xmax. 32hz is that best value at 63v in the ss15.

The T48's in the 2007 shootout were Leland's cabinets with 3015lf's. After the T36 fiasco, where everyone found out that a customer built and measured (indoors) a T36, and that bill had never built/tested it... well, indoor measurements mean nothing... and that's why for 3YEARS no one could replicate the posted measurements.... Well I posted the 2007 shootout measurements and questioned if the posted T48 measurements that look nothing like the 2007 shootout numbers were indoors as well. I was banned from BFM land, and all posts deleted within minutes.... So, no... I'm no BFM fan, and I didn't save any of my BFM cabinet measurements when the hot dogs were roasted.

The one thing that is very true of BFM horns, they like a corner.... that's the one place they are happy. A big advantage of TH's, they are directional and don't need a corner.

If you find my thread on the 'stadium horns' that I built using 3015lf's, you'll find a real 30hz option... and several posts about the whole BFM mess. Stadium horns are anything but portable, and you can only drive them to 50v or so safely. The SS15 is the 'balanced' option between loud and low, that's really the best bet in my opinion.

Don't want anyone to think I'm trashing anyone's design's... just facts and history.
 
At one rave that we ran sound for 2 months ago, we got some really good bass though, 2 cornerloaded T48s in a room that is about 7x12m, 2,7m ceilings, one sub in each corner of one short wall. The place was more or less coming apart :p

I would expect exactly this given the frequency response of the T48. I would imagine they are not as good outside in a field or under some tops in front of a stage.
 
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