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Lascala Bass Bin Mod


rtaylor

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Homemade, the "constricted" throat that you are referencing is simply an acoustic filtering slot and is technically not part of the throat of the horn; its actually called a throat cavity opening or filter (to keep the nomenclature straight). In all of the Klipsch horns the slot is smaller than the throat cavity cross-sectional area. It is made smaller (at 3x13") to drive up (and smooth out) the supposed dip of the K33E response at around 400Hz according to an article by PWK. I always assumed that it was actually a peak in the response, not a dip, but I digress...

The slot itself technically is not a true throat constriction, it is a physical acoustic slot filter.

The slot opening can be widened to the maximum of 6x13 inches for a 1:1 match with the throat area, especially recommended when using a driver other than a K33E.

{edit} I should add that the horn throat itself is the portion of the horn that is dimensionally the smallest.

It is NOT the hole in the end of the horn in this case, although in other horns, especially round-ones where the horn walls actually form part of the hole, that could be the case. I hope that I haven't confused anyone.

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Marvel, no problem! Here's a link to the thread on the Oris forum: http://www.bd-design.info/forum/reply.php?id=6640,6640

Homemade, the EQ is done by a hipass filter with Q=2 at 31Hz. This is the same as 6dB EQ at 31Hz. I have a spreadsheet simulating this but unfortunately I don't no how to post a graph from it. With no room effects the ported/EQ'ed box is almost flat from 30Hz, and the sealed stock box is almost 14dB down compared to this. Above ~100Hz there isn't much effect from the porting/EQ'ing, but here the horn loading starts. So the combination of the horn and the port/EQ makes the response quite flate.

Frode

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http://db.audioasylum.com/cgi/m.mpl?forum=hug&n=75836&highlight=high+Q+filter+djk&r=&session=

http://db.audioasylum.com/cgi/m.mpl?forum=hug&n=76120&highlight=high+Q+filter+djk&session=

"Just because a modified speaker has 0db change at a certain freq. doesn't mean it's automatically a phase cancellation problem."

An 11dB change at 40hz wrt 50hz is hardly 'zero'.

Me: Are you saying the constricted throat has absolutely no bearing on how the woofer behaves at lower frequencies? Do you have data to back this up? I still don't understand your reference to white and rotary knobs and POS. Maybe your attitude is POS!

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=23788&item=7308820616&rd=1&ssPageName=WDVW

http://search.ebay.com/White-equalizer_W0QQsofocusZbsQQsbrftogZ1QQfromZR10QQsacatZ-1QQsargnZ-1QQsaslcZ2QQsadisZ200QQfposZQ5AIPQ2FPostalQQga10244Z10425QQftrtZ1QQftrvZ1QQfsopZ2QQfsooZ2

You can't think straight and have no common sense, I would call you a moron, but that wouldn't be polite.

According to your ideas of how things work, I can just mount a constricting slot in front of a woofer and it will suddenly be horn loaded.

Did you sleep through 8th grade science?

You are a huge time waster, do us all a favor and don't bother to read anything I post, PLEASE!

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DJK: Where's the moderator on this forum? Calling people morons and failing 8th grade science is not needed. Where are your manors? I will check the links you provided and check them out. Look, all I said was that with all the work going into the boxes you're not going to get flat response without an eq. of some sorts and Marvel explained it pretty well. I still don't understand your opinion of a 10band eq. being a POS. Where's your data to back this up? My reference to the throat as messing things up for the math involved was not the same as saying a restrictor in the front of the woofer will make it a horn-djk.

I know that my khorn's back enclosure is very small and making a cabinet the same size and putting the 15inch woofer in it will sound terrible-way too high of Q and resonant freq.-I haven't figured out what it is because I don't know what the specs on my speaker (or the K33e) are. On my literature of the La Scala it shows a 5db dip from 40hz to 35hz and than back up again at 30hz. Perhaps this is the dip at 40hz that Forde is experiencing. Look, if we're using an eq. anyway why not make it a multibanded one and tame the upper bass?

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Very informative posts. Homemade, what DJK means about POS 10 band eq is that the internal parts used on the majority of consumer-home stereo eq's and even some pro gear eq's are junk and a POS-low quality internal parts. Hence the 10 band eq is a POS due to junky POS low quality parts used. White makes some of the best pro gear eq's around, no junk POS internal parts used-high quality parts are used. White eq's are expensive, a well respected company that makes an excellent product. If I remember correctly White is a Texas company.

Regards, Mike

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Homemade,

The K33E is made for Klipsch by Eminence. These are the specs on the part (you can't buy the speaker from Eminence):


SPEC 15162

PART # K-33

RE OHMS 3.39 FS HZ 34.46

LE MH .96 MMS GMS 78.59

QM 7.39 CMS mm/N .2714

QE .410 RMS NS/M 2.3037

QT .390 VAS LTRS 301.66

XMAX MM 8.20 SD SCM 889.59

BL TM 11.88 EBP 84.4

EFF % 2.91 SPL dB 96.6

Wattage 150rms

Cheers,

Marvel

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D-Man, Please don't harpoon me for asking a dumb question...do you know what the net horn loaded impedence would be for a K43 using the larger 6 X 13 slot. Am I ASSuming correctly that this is the slot size you would recommend for the K43? Having asked that...would this not have adverse effects if one were to use the larger slot with the BASS BIN MOD?

Another question I have is I've heard the K33 is more "musical" than the K43, but if I understand it correctly this mod favors the K43. That said, does one woofer still hold an edge over the other??? Opinions anyone??

THANKS

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That's a good question, I don't know.

The K33E has a 2" dia. vc which limits it wattage-wise, where the K43 has a 3" vc and is rated for higher wattage.

I don't know about the differences in frequency response, only that the K43 doesn't go as quite as low and is not as sensitive. It probably would also use the narrow slot, but I really don't know, so this is speculation. The guys with the professional/industrial LS's would be able to answer that one.

The reactance at the throat would appear lower to any driver when using a wider slot opening as compared to the narrow one, of course. This effect of lessened reactance allows the use of 8 Ohm woofers vs. the 3.4 Ohm (4) K33E. The impedance tests on the K33E by John Warren indicates approx 6.3 Ohms overall when loaded in the Khorn. This may be slightly less when loaded in an LS or a Belle, in that the shorter horn paths and higher Fc of the horns present less resistance to the cone.

{edit} I try not to harpoon anybody. I only hope that I can answer questions with a somewhat correct answer, or offer some tidbit of interest! Ain't always the case...

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Thanks Marvel for the specs on the K33E. I'm personally running some Eminence speakers in my homebuilt khorns that I purchased 15 yrs ago from McGee Radio out of K.C. The only specs listed on them in the catalog was a 2inch vc, apparently 32hz fo and 92 db efficiency. They have a 54 oz magnet. They do appear to have a little less efficiency than the K33E but I'm running the 8ohm version instead of 4 ohm and the efficiency matches up perfectly with my Audix6.5 inch midrange driver rated at 99.6db efficiency. They listed an enclosure of 2.75 cu ft and a port of 4 inches dia. and 5inches long. I haven't calculated out the woofer specs from there but probably too many variables to get an acurate idea of specs and who knows if they actually went by any thiele measurements when they said what box size to use. The 4ohm version is said to have 93 db efficiency. Does Eminence even make any non musical type speakers anymore? They said in the add for the speaker that it was a good khorn replacement speaker. Perhaps a little low in effieciency though unless one used the 4ohm version.

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OK, need some help here. Can the AA's or AL's that I have here be modified for the bass bin mod? Do I need an equalizer? Does anyone have a diagram of the mod if it is possible? Thanks everyone, Randy

EDIT: This is for 1986 Lascala's with the K33 and unstock AA's hopefully.

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On 3/25/2005 8:30:05 PM homemade wrote:

... Does Eminence even make any non musical type speakers anymore? ...

----------------

I'm not sure what you mean here. They manufacture speakers for other companies, Klipsch being one of them. The K33 is priced around $130, which is not a bad price for what it does. They will make them to your specs if you want, but you need to get a fairly large quantity before the price per speaker is reasonable.

Marvel

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Have you considered ALK networks or ALK kits? I use them in my 84 La Scala Mains and my 86 La Scala Center. There is a definite bass improvement as well as significant improvements across the board. They produce an incredibly detailed an articulated sound. I believe the primary limiting factor on your bass is essentially the ability of the bass horn/bin to produce the lower frequencies. If the enclosure can do it the network should not inhibit it, they should be essentially a flat bad pass across the drivers/enclosures/horns frequncy spectrum/capabilities.

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Randy, from what I've read and 'think' I understand you need to equalize prior to amplification. That said, IF you can trust this filter s/w I have... a Q=2 31hz 6 ohm high pass, 2nd order 'passive' filter requires

C1= 1711.83 uF

L1= 15.41 mH

in addition to the low pass you already have...I guess this would in effect make a bandpass for the woofer. Then again I could be totally WRONG! I don't want to lead you down the wrong path and I am unsure if you'd really see the 12db gain at the crossover point. So PLEASE check with someone else. I also think you'd go broke buying the caps...IF this would even work. If it won't maybe someone can explain and we'll both learn something!

BTW, thanks D-Man...a partial answer helped though I'm still on the fence for a K33 vs K43. I'm leaning toward selling my K33's and buying the $250 ea K43's. I started this whole endevor trying to save some $$$ doing a scratch built modified LS. Unfortunately, the more I read the more I spend. It's getting to the point I don't want to add up all of my receipts. If I didn't know better I'd swear I was building a BOAT 8.gif

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On 3/26/2005 8:45:32 PM Rockets wrote:

... It's getting to the point I don't want to add up all of my receipts. If I didn't know better I'd swear I was building a BOAT
8.gif

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LOL

boat \ 'bōt \ n. 1: a small vessel propelled by oars or paddles or by sail or power 2: a hole in the water you throw money in

Marvel

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OK, I get it now. I have to increase the frequencies before the amp other wise all the other frequencies would have to be attenuated. Is there a simple way for me to do this? Or is a quality equalizer the answer. I've always tried to keep away from adding any more stages in the system. Sorry for all the questions but I'm a simple man with a beer in hand. Randy

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