A question on compression drivers ... am i in the right place ?

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#61
bear said:
If ur listening at 100dB @ 3meters, ur listing reasonably loud, fyi
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Hi and thanks a lot. Let's say that i have no clue ... i was say 100dB peaks
Ok ... i will buy a SPL meter ... it has been always a curiosity of mine to see the peaks reached when playing music and i will report.

What I was saying is that IF you rely upon the lower freq driver (not the horn) to go low into the bass, you will have to give up some sensitivity, need a rather large enclosure and have a limited range of driver choices.
Click to expand...

I would be very satisfied to get from 50 to 15kHz .... no more
I am 52 and i think my ears dont go much higher.
I am not interested to walls shaking bass as well.

Otoh, if you give up on the LF (more or less) and concentrate on "best response" from say 100Hz up (even if it turns out to go lower) and highest sensitivity and/or lowest 2nd & 3rd THD drivers, you'll find you have a far wider range of choices, and you'll need a smaller enclosure.
But you will still need some sort of sub eventually.
A tapped horn is not a bad choice... but given that you can amplify the sub the sensitivity becomes reasonably irrelevant, just use a big cheap amp and a driver that has the right parameters and high enough power handling.
Fwiw, just using a "horn" and a "compression driver" does not assure you of either flat response or nil distortion.
_-_-
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100 Hz is a little high as low limit ...
Anyway i will think about it, I understand it will be not easy.
In the meantime i bought a a spl meter ... just to have an idea of the peaks
This one ... what you think ?

http://www.ebay.com/itm/161343333275
$_57.JPG


Thanks a lot again, gino
 
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#62
Hi to Everyone ! Pyle drivers received ... exit throat 2" !!!! :happy1:

Curious i removed the back cover ... the diaphragm is glued to the cover that is plastic !!!!
I was sadly surprised ... i thought that the diaphragm was detached from the cover like in some picture i have seen.

Anyway now the search is on for a 2" horn
Which i have no clue at all. I read that shallow horns are better ?
They call them waveguides i think.
If anyone has a kind suggestion i would appreciate so much
Thanks again to All. Kind regards, gino
 
#67
Studio Au said:
http://www.diyaudio.com/forums/vendors-bazaar/257692-uk-made-turned-horns.html
Custom Profiles
From £125 pair, 1.6Khz JMLC
Click to expand...

Hi and thanks again for the reply
They are really splendid actually ...
One question ... i have been told that to go lower in freq bigger horns are needed
My problem is to understand how big must be an horn with a 2" throat to get down to let's say 800 Hz
Is there some kind of formula linking low cut freq and horn size ?
Thanks a lot again. Very beautiful.
Kind regards, gino
 
#69
Studio Au said:
Yes the lower the frequency the bigger the horn. Here is the JMLC spreadsheet as provided by Jean-Michel.
https://dl.dropboxusercontent.com/u/1444609/diyaudio/2014/JMLC_horn_v2.xls
Click to expand...

Thank you very much again. This is what i was looking for actually.
To get an idea of the dimensions.
i would like to explain my main concern a little.
The few times that i have listened to horns the bass was traditional ... i mean a woofer in a box.
I have always felt some kind of "detachment" between the horn and the bass ... like something not omogenous ... maybe it was just me.
Maybe the reason is that the horns were so extraordinary that the woofers cannot be on the same level.
I am sure that the big speakers where also the bass is horn loaded are the best possible. But they are for big rooms ... unfortunately not my actual situation.

The DIY site of AutoTech Horns, has dimensions and recommended crossovers to give you an idea of how big they get.
The one linked below has an acoustic cut off of 600Hz with a recommended crossover of 900Hz, and is 321mm across.
Horns
Click to expand...

Well not that big actually ... i thought more.
Do they terminate the horn for different throat size on request ?
I mean i do not see the mounting flange.
Really beautiful ... i need to make some experiments for now
I am sure i will end with better quality drivers ... and these horns look the right companion indeed, both execution.
Have you tried both maybe ? the material matters ?
Thanks a lot again, gino
 
#70
The LeCleach xls is not protected.

I suggest you go to format cells and protect for each sheet.
Then go to sheet 1 and highlight the 5 RED cells and format cells untick protect.
tools protection click
then go to sheet 2 and highlight the 4 RED cells and format cells untick protect.
tools protection click

I don't use a password.
Just leave it blank (no entry) and save.
It allows me to unprotect without having to type in any password.
You may want to unprotect if you decide to change the 344m/s for air speed.
 
#71
Thanks a lot again but this is too difficult for me
I will buy an off the shelf horn with a 2" throat relying on the info from the manufacturer and on the size of the horn.
This is applied math ... my nightmare
My math is at "grocery" level
Thanks but this is too difficult for me
Kind regards, gino
 
#72
Oh, time and space, that's where the sound's located.
Usually for waveguides, which are not horns ( or better: they can be used
with normal drivers, such dome tweeters ) the math is easy.
You obtain the maximum wavelenght allowed by the WG by
dividing the velocity of sound, 344 m/s, by the diameter of the WG
So with a 34 cm diameter WG you can reproduce till 1 kHz...or 1000 Hz
( 344/0.34=1000 )
 
#73
Hi and thanks a lot for the kind and valuable explanation

I have another question ... also very trivial

What influences more the freq response ... the horn or the driver ?

I mean ... given different drivers but with:
1) same coil size and
2) same exit throat
3) mounted on the same horn
will they give a similar response ? 🙄

Sorry bu i am trying to understand if some basic and practical rules exist
Thanks a lot again, gino
 
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