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Multi-Way Conventional loudspeakers with crossovers

Small La Scala Tutorial for noob
Small La Scala Tutorial for noob
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Old 12th March 2019, 05:19 AM   #11
sumotan is offline sumotan  Indonesia
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Thank you kindly GM for the advice . I did find some info on the EM10-100 but not detailed FS 100hz. Think it might be an old Eminence. So basically I should be looking for woofers with very high Qes ?
Question pls: will the frequency in this box not go higher even if I set the electrical XO at say 600 hz ?

Thank you again
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Old 12th March 2019, 05:44 PM   #12
freddi is offline freddi  United States
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Small La Scala Tutorial for noob
due to various problems - then winter with no heat in my big room (to save $), I've not yet loaded my "baby" Belle. It should run ok with my 12pe32 or Kappa12a. That's a Klipsch K700 horn (from Heresy I) sitting on top for size comparison. The initial problem was with a thin spacer warping when trying to load a speaker - there has to be something to keep the cone from hitting the throat plate.


A Question - - GM, when using hornresp and looking at the directivity of these little midbass, its typical to see a predicted on-axis rise of 7dB or more vs "flat" response. In practice - does that happen? (didn't see that with the 100Hz "hypex" Edgarhorn and 2220H on-axis outdoors) What I think may have happened was it was "flat" on axis and would have dropped that much off axis at a certain point. Maybe its case by case ?

Here's how hornresp shows a horn scaled roughly from John Inlow's drawing of his 135Hz horn. The back chamber is pretty tight
so M151's xmax would not be exceeded at 40v (it might just burn up - hahaha)

Click the image to open in full size.



Click the image to open in full size.

Last edited by freddi; 12th March 2019 at 06:12 PM.
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Old 13th March 2019, 02:01 AM   #13
GM is offline GM  United States
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Quote:
Originally Posted by sumotan View Post
Thank you kindly GM for the advice . I did find some info on the EM10-100 but not detailed FS 100hz. Think it might be an old Eminence. So basically I should be looking for woofers with very high Qes ?
Question pls: will the frequency in this box not go higher even if I set the electrical XO at say 600 hz ?

Thank you again
You're welcome!

The way it works is one needs a really low/'powerful' Qes/Qts for the HF [~0.1] since each octave is so wide and horns can only do ~three octaves and as we move down in frequency it increases [progressively 'weaker' motor] because the throats, horn need to be bigger due to increasing WL size, narrower BW in three octaves; so yes, down low where the horn is only covering a narrow BW, then no need for much HF extension = high Qes/Qts.

Of course you can use more powerful motors to squeeze more than three octaves out, but compression ratios get extreme unless multiple drivers are used, but the LF suffers, so in the end it's always about trading efficiency for BW.

Not familiar with the Klipsch horns beyond what was recently posted, so nothing about yours, but once above the driver's mass corner, first it rolls off due to decreasing air loading, then inductively rolls off just like Keele shows, so while it will have some extension it will need EQ and what normally is done is to use CD horn EQ to flatten the horn's response down to the driver's, i.e. trading efficiency for BW. Not many 'free lunches' in acoustics.

GM
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Old 13th March 2019, 02:24 AM   #14
GM is offline GM  United States
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Quote:
Originally Posted by freddi View Post
A Question - - GM, when using hornresp and looking at the directivity of these little midbass, its typical to see a predicted on-axis rise of 7dB or more vs "flat" response. In practice - does that happen?

Here's how hornresp shows a horn scaled roughly from John Inlow's drawing of his 135Hz horn. The back chamber is pretty tight
DB would have to answer that since I've never measured it nor felt the need to pay much attention to it since I relied on the known excellent HF hearing of others, though IIRC I've got some some accurate Altec polars I can check.

I do know that the ones done for deep cone [Altec] and shallow cone [JBL] woofers showed that Altec's pretty much followed the piston chart whereas the JBL's were 'all over the map', though apparently due to more flex, so would think that a horn would be similar to the piston if just basically a horn, i.e. not multi-cell, Smith, etc..

Well, if the compression chamber is tuned too high, then it will have a rising response like simmed, so tune it to the horn's BW mean for best overall performance: [Fl*Fh]^0.5

GM
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Old 13th March 2019, 03:39 AM   #15
freddi is offline freddi  United States
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Small La Scala Tutorial for noob
hey GM - what might I be doing wrong with regards to wanting to "down-scale" a La Scala model in hornresp via the resize wizard ? - its telling me I can't go lower than "1.01" and I've done 0/7, whatever in the past with no problem.
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Old 13th March 2019, 04:13 AM   #16
sumotan is offline sumotan  Indonesia
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Thank you again GM for the tutorial. Well Im not greedy for lows perhaps 60-70 hz. Lol What I would want to attain is to be able to crossover at around 600-700hz to make a 2 way. I was looking into the Klipsch horn site & aparently someone had measured the La Scala bass bin to go up too 700hz or so with a dip at 500hz. Now if we calculate base on 2xFs/Qes, those woofers too will not make it pass 400 hz. Can I speculate that the slotted mouth woofer opening plays a part too to allow a higher xo frequency ?

Cheers
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Old 13th March 2019, 04:22 AM   #17
GM is offline GM  United States
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No clue, never played with it, but just now took a huge 515-8G 30 Hz expo and it did a 0.7, then 0.5, then did a 0.5 to the 0.7, so dunno. Nifty feature/tool though!

Post your La Scala record, so I can try, 'eyeball' it if I can't.

GM
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Old 13th March 2019, 04:47 AM   #18
sumotan is offline sumotan  Indonesia
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Far GM & thank you.
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Old 13th March 2019, 05:40 AM   #19
freddi is offline freddi  United States
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hi GM- maybe hornresp got damaged when my pc hung up due to low RAM ? I ran the newest setup but that did not fix things - look at he error message

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Old 13th March 2019, 05:45 AM   #20
GM is offline GM  United States
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Originally Posted by sumotan View Post
Thank you again GM for the tutorial.
You're welcome!

Well, the slot area frequency*~0.81 sets the horn's upper cutoff if that's what you're asking.

Anyway, 'sounds' like they used a vintage style horn driver, which makes sense since it's a vintage design and what what guitar driver design are based on, i.e. has a wide BW breakup modes BW to fill in above the horn's roll-off same as the old Altec, JBL small theater/PA horns and since it rolls off around 400 Hz, the dip at ~500 Hz is about right, so a quick trip to Eminence turned up this, which is probably about the best you can do nowadays unless JBL or other cinema sound folks has something better: Speaker Detail | Eminence Speaker

GM
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