JBL 2482 phenolics OR horn loaded cone driver for low-mids?

Hello,

For my horn rig I am looking for a low-mid driver (horn loaded).

The driver shall cover from app. 180-600 Hz (or maybe higher depending on the driver).

However, I have not decided whether to go for a compression driver or a cone driver.

If I go for a compression driver it will almost certainly be a pair of vintage JBL 2482 phenolics mounted on straight, circular 140 Hz tractrix horns (as far as I know no other compression driver - that I can afford - will go that low).

If I go for a cone driver it will either be a pair of Fane Studio 8M, Precision Devices PD.107 (both already available), or Electro Voice EVM10M or DL10X. I have not decided yet which horn to use for any of the cone drivers.

I will use digital (high order) active crossovers, so driver protection should not be an issue. The large, straight 29 Hz bass horns that I use beneath the sought for combo do work up to 350 Hz or so (they are loaded with high EBP drivers), but I would prefer a clearer and more “open” low-mid section:)

What route should I take? I would especially appreciate to hear from those of you who might have actually compared the JBL 2482 as low mids to a hornloaded cone driver. Obviously, I would also like to hear from people having experiences with the cone drivers I mention.

Thanks a lot for your time and suggestions!

Kind regards
Peter
 
Hello, the JBL won't go that low in that horn. Best used to 300 cycles.

What will determine my recommendation will require disclosure of your high frequency horns and drivers.

Most cone 10's are only good to 800 to 1000 cycles when horn loaded if you expect them to be linear.

The JBL 2482 is good to 5-6K if the magnet is fully charged. I have to say though it will beam badly in that big of a horn.

gi.mpl


Your bass horn looks wild....
 
Hi Magnetar,

Thanks for replying! I have never had a chance to hear or measure the JBL 2482 myself (which I had, but unfortunately Denmark is not a horn-country):bawling: However, I think I remember John Sheerin reporting (please correct me if you are there, and I'm wrong John) that his quite similar Dukane (JBL) phenol driver loading down to 100 Hz provided that the horn loaded that far down, and since the 140 Hz horn is 90 cm or almost 3 ft long it should load a given driver down to app. 190 Hz in free space. But, again this is not based on my own experience, but only of what I have heard and simple calculations, so I may be wrong.....

The mids and highs:
I have a pair of 2" Community M200A on their way and already have a pair of 1" B&C DE25 for the highs. I will use circular tractrix horns for both of these. So far I have only got a pair of small 800 Hz tractrix horns, but Stereo Lab in Germany sells their tractrix horns in different sizes and at fair prices. So I will probably buy the 'missing' mid horns from them. If I go for the 2482, I may leave out the M200A and cross between the 2482 and the B&C at 1500 Hz or so.

And if I take the other route and go for a cone mid-low driver, I intend to cross over to the M200A somewhere in the 500-800 range and cross again between the Community and the B&C at 4k, where the M200A rolls off.

Kind regards
Peter
 
Magnetar said:
Hello, the JBL won't go that low in that horn. Best used to 300 cycles.

What will determine my recommendation will require disclosure of your high frequency horns and drivers.

Most cone 10's are only good to 800 to 1000 cycles when horn loaded if you expect them to be linear.

The JBL 2482 is good to 5-6K if the magnet is fully charged. I have to say though it will beam badly in that big of a horn.

gi.mpl


Your bass horn looks wild....


I take the last sentence as a complement:)

Kind regards
Peter
 
I have a 180 hx tractrix and 2482 and it will not go that low. 350 is where it stops. Maybe lower in a long expo horn but not a tractrix.

I would go for the cone driver and use it 180 to where it rolls off on it's own, then bring in the M200, You should first see how the M200 does loaded in the horn first (how low it goes and how it performs) . That 800 Hz horn I presume is for the B&C treble?

Your system will be HUGE - this is one reason why I went to multi driver dipole bass and have not looked back
 
Hi Magnetar,

Thanks for the suggestion. Yes, the 800 Hz tractrix is intended for the 1" B&C driver. The system is huge for sure. But the basement room was there and horns do certain things very well!

BTW, I know that you have tried a LOT of drivers, which makes me ask whether you have experience with any of the cone drivers I listed in the original post? Thanks!

Kind regards
Peter
 
No I have not used any of those. McBeans program is very good to help model drivers on the bottom end. Maybe you should do some modeling with the prospects first. I think a hypex or expo horn will be better for that range. The biggest tractrix I have used was 100 hz quarter space and it barely loaded to 200 when used off the floor.
 
The 2123 is warmer, and more 'romantic' sounding in the lower range. It also will keep up well with the rest of the system. The 2482 will cover a much wider range though and would be superb mated with the B&C treble. - hmmmmm Those straight bass horns to me are a dilemma. I always used folded horns for the low bass and kept them separated Yours probably sound better in the bass but appear to be difficult to mate with the rest of the system. Looking at it I think I would place the low mid horn up high tilted down and cross over around 150 cycles using a 10 , below it a large format compression driver around 600-800 cycles then to the little B&C. The upper mid and treble horns would go between the bass horns and the mid bass horns.
 
http://www.volvotreter.de/
conical_horn_setup_13.jpg


The conical could easily have strong panel /mouth reflections in top of band-
3.4m wavelength 100hz, up to 0.34m at 1khz

Perhaps
- last 1/3 of flare,double included angle 'eases' the pattern flip a little.
id be tempted to squeeze the vertical to achieve a more CD response horizontally

DIY Axially symmetric oblate spheroid CD waveguides, in solid Oak
http://www.audioheritage.org/vbulletin/showthread.php?p=196422



http://www.xlrtechs.com/dbkeele.com/PDF/Keele (1975-05 AES Preprint) - Whats So Sacred Exp Horns.pdf
 
Magnetar said:
The 2123 is warmer, and more 'romantic' sounding in the lower range. It also will keep up well with the rest of the system. The 2482 will cover a much wider range though and would be superb mated with the B&C treble. - hmmmmm Those straight bass horns to me are a dilemma. I always used folded horns for the low bass and kept them separated Yours probably sound better in the bass but appear to be difficult to mate with the rest of the system. Looking at it I think I would place the low mid horn up high tilted down and cross over around 150 cycles using a 10 , below it a large format compression driver around 600-800 cycles then to the little B&C. The upper mid and treble horns would go between the bass horns and the mid bass horns.

Hi Magnetar,

Thanks for sharing your experiences! I think my bass horns do sound very good indeed. I never had such punch with direct radiators. I just think that they - probably because of the length of the horns - do not sound as open as I would like above, say, 150-200 Hz or so. If I go for the cone low-mid, then your suggestion sounds very good indeed!

Kind regards
Peter
 

Scott L

Member
Paid Member
2008-12-27 12:32 pm
Knoxville, TN
cd vs mid vs mid-bass

I will support the statement that the jbl2482 won't go lower than 300hz. I have had a number of different cd's in big horns. The BMS 4592 goes lower. A cone such as the audax pr170 goes down to around 200hz, which I have tried but found it sounded thin.


A compression driver loaded into a large horn may show response that low, but, will it play the note ? Of course not, it can't grip the air.

The pr170 series drivers are mid range drivers, again, not made for anything
low.

A 10 inch mid bass, especially horn loaded, will play the music. However,
I can't say whether a 10 inch is the optimum size.