typical sensitivity of 4-5" cone driver on mid horn?

[freddi]

20 some years ago I ran JBL LE5-2 on 2.5" x 2.5" 250Hz tractrix horns as mids. I don't know if those LE5-2 were even in spec then. Today the one I tried has fs ~340 and qts ~2. It seems to behave well on the horn gapped around 1/4" from the throat.

I have a new 7 cubic foot folded midbass horn loaded with a Community "buyout" 12" speaker, so pulled out the LE5-2/250H tractrix and guess its around 100dB. Below is a comparison of it vs the midbass horn vs an Altec 511 with ancient alnico University SA-HF. Then a comparison of somewhat stronger but more limited on top Selenium Trio 250 also on a 511.

I would have to biamp if using the JBL cone-driven horn. Out of laziness I'll probably try to blend the Selenium to the midbass and add a tweeter around 2K5.

There's an "RT4" sealed back midrange at Ebay - I wonder if its about as hot as the LE5 and roughly its extension on tractrix like mine.

Are there inexpensive 4-5" cone speaker candidates today which work well on midhorns like mine? What kind of sensitively can one expect?

 

[POOH]

The closed back RT4 doesn't load so well below 350 hz but compared to LE5 will be more sensitive (maybe 3-4db) in the midrange and more extended and smooth on top compared to the JBL.

I like the B&C 6pev13 and Faital proM5N12 - both will go lower and outperform LE5 in a front horn

 

[freddi]

thanks for the info POOH - do you use RT4 like a Unity or clustered together at the throat in your mono rig?

 

[POOH]

thanks for the info POOH - do you use RT4 like a Unity or clustered together at the throat in your mono rig?

No in a line. Of the above I mentioned I would take the B&C but it's only good to around 2.5k on top in round 180 flare tractrix with 4: throat, maybe 2.6 in a 3" thraot

 

[freddi]

is that a line as with a rectangular horn throat ? - or as a direct radiator line array ?

 

[POOH]

Horn loaded rectangular throat - conical plywood horn with 1" driver centered with 2 of the 4" below and two above in the throat, sounds great in mono - too lazy to build a second horn 32" square mouth , maybe someday- these are really nice sounding horn drivers for cheap

 

[freddi]

Cool - there's plenty of good music in mono - or you can listen twice to stereo recordings - one channel at at time

 

[POOH]

Mostly feed it mono signal from laptop to soundcard to triode streaming audio from Tapin Radio software - Like 75 thousand stations - plenty of opera

Raimersoft - TapinRadio

Cool - there's plenty of good music in mono - or you can listen twice to stereo recordings - one channel at at time

 

[freddi]

big thanks POOH for the radio app.

there seems to be a lot of mono albums uploaded to Youtube


There's a lot of older public domain music at Archive.org and pretty good transfers - here's some


public domain 78 and lp transfers by F. Reeder - huge amount of classical stuff

http://archive.org/search.php?query...:audio+AND+collection:opensource_audio&page=3

great transfer of the first act of Die Walkure 1935 with Lauritz Mechior, Emanuel List, Lotte Lehman by "Bigshot"
http://www.vintageip.com/xfers/walkureact1walter1935.mp3

details in a post http://www.diyaudio.com/forums/anal...-shellac-discussion-thread-3.html#post4341092

F. Reeder's transfers of 1920's Pop music
https://archive.org/details/1920sPOP-CompleteNewTransfers

!920's to 40's music from a radio show "The Big Broadcast"
https://archive.org/details/1920s78Recordings

Voices Of Christmas Past 1898 to 1922
https://archive.org/details/Voices_of_Christmas_Past_1898_to_1922

Collected works of Enrico Caruso Vol. 1
https://archive.org/details/Caruso_part1

Vol. 2
https://archive.org/details/Caruso_part2

 

[freddi]

that little C-path midbass built for me is cute in 2-tone and light for its stiffness as most of the cabinet is made of 5/8" Baltic birch other than the baffle and lid which are 3/4" BB
http://i.imgur.com/7E9h3Bz.jpg

 

[freddi]

looks like those RT4 are gone - I would have picked them up but the seller's checkout would not combine shipping. Are there substitutes for the RT4 ? my LE5 just don't have the output on a tractrix to keep up with the midbass.

 

[hollowboy]

I think I got 100dB from a standard 4" driver (P.Audio SN4-60F). The plot in the link shows the 4" cone versus a JBL 2445J, and the cone driver is ~10dB lower than the JBL's maximum level (which should be 110dB / watt).

This is with no rear chamber on the 4". Later, with some tweaking, I managed to get smooth (but slightly sagging) response to 6kHz.

The PRV audio drivers that X likes should be similar, but a couple of dB louder.

http://www.diyaudio.com/forums/mult...axial-mounting-midrange-horn.html#post4686481

 

[freddi]

cool - I need something to keep up with this little horn - its not the hottest thing but sims close to 105/2pi - - is it tough to get real world 1pi results from small speakers at floor/back wall position? - being the old University S9 fold scaled down, its unknown how it will actually play

 

[freddi]

found the R-T4 - will see how they do on the old Edgar 250 tractrix with 2.5x2.5" mouth

 

[CFT]

Possible to use a conventional 4 or 5" full range driver on a JBL PT-K95MH or PT-K64MH waveguide for both high and mid anyone?
And, is the JBL a good choice? Thanks!

 

[hollowboy]

Possible to use a conventional 4 or 5" full range driver on a JBL PT-K95MH or PT-K64MH waveguide for both high and mid anyone?
And, is the JBL a good choice? Thanks!

The PT-K95MH looks pretty good. I'd have tried a pair if I had found them cheaply & locally.

How big is the throat? It looks like it would it be roughly 1:1 with the drivers you are considering.

Are you aiming for a minimalist rig, or would you be OK with digital eq?

If you mean to use a 4" and a 1", then 300Hz & 2kHz crossover points and a 100dB/watt system should be easy.

If you mean you want another FAST, with the 4" driver to cover everything >300Hz, that's a bit tricky.

If so, another horn to consider: the Azura AH-204 built for a 4" throat.

The Azura site has the only good measurement of a 'conventional' 8" full range driver on a 1:1 throat front horn I've seen:
http://www.azurahorn.com/lowther_on_160.pdf
Presumably Oris and other (similar) horns are more alike than different.

The big problem with the 8" seems to be that the horn loading is over by ~800Hz, and then there is a massive rise at ~2200Hz ...leaving a 10dB hole right in the middle.

Therefore a 4" throat version looks like a great option for a minimalist FAST. In similar experiments, I got substantial loading up to 2kHz. Too much loading! The ideal driver (for a minimalist system) would have a rise of about 10dB to 2kHz, then be flat to 20kHz ...but I don't know of a 4" or 5" driver with that much rise. 5dB seems to be about the most.

Three different drivers in similar horns trialed / discussed here. They all needed about 5dB cut <2kHz.

http://www.diyaudio.com/forums/full-range/280220-fostex-ff105wk-conical-horn-2.html

The TB driver pictured (from a Québécois blog) is one that I think looks good, but again, not enough rise.

 

[CFT]

Thank you for the reply and the links, very informative!

Yes, its for a FAST and a minidsp is available.

That JBL waveguide is relatively compact I suppose..and it can fit 5 inch drivers while Azura or Oris a bit big for me..

Tricky for the JBL? You mean that 2khz step as in your findings?

I will do some more studying and this is a good start for me..thanks so much! Drivers will be Coral 4" and 5".

 

[CFT]

cheap-jack-audio

How about this 15"x10"JBL mid waveguide if still available?

Perhaps its a better fit? Its found in JBL PRX535 3-way speakers....xover @430 Hz.

What should I expect from this one at the higher freqs? Could EQ help to be a remedy?

 

[hollowboy]

Yes, its for a FAST and a minidsp is available.

Tricky for the JBL? You mean that 2khz step as in your findings?

DSP makes it much easier.

That JBL waveguide is relatively compact I suppose..and it can fit 5 inch drivers while Azura or Oris a bit big for me..

You basically trade size vs LF cutoff and ripple. But the price is right, and sometimes it makes sense to get a smallish horn (low postage costs, wider availability), and then extend the mouth yourself.

The Azura I mentioned is more $ but looks nice, can have a mouth size of 'only' 650mm, and have a throat built to suit whatever driver you want. The price is pretty low for a boutique item made by an enthusiast: about 60% of the price of the Oris 250 horn. Made by an Australian, so I'm biased

I will do some more studying and this is a good start for me..thanks so much! Drivers will be Coral 4" and 5".

If they have ultra light (flexy) cones, they may not suit horn loading. If they are uneven in the mids, or have objectionable breakup spikes, I'd suggest trying a pro wideband such as the PRV, or the P.Audio (or anything with a stiffer cone).

What should I expect from this one at the higher freqs? Could EQ help to be a remedy?

TL;DR: the horn does nothing to HF. EQ to taste.

Long version:

Based on 4" specs and polars, such as this:

Soundlabs Group R 10 S - 4 Ohm

...this driver's opening angle (-6 dB) is 92°/4000 Hz

If your horn has a 90 degree pattern, a 4" or 5" driver's beaming will be narrower than this for the top 2 to 3 octaves, so the horn will have no effect on HF. EQ will be dependent on the driver's HF response and whatever measures / sounds good to you.

Note that while my 4" cone driver driver had some ~15dB breakup spikes >10kHz, the titanium compression driver had the same thing but worse. So while a 4" with eq won't be perfect for HF, it should be better than what you'd hear at a lot of live shows.

 

[CFT]

Thanks for your detailed reply and its much clearer to me now.

Yes, I am familiar with the Azura horn, my hifi buddy has used them on top of his Klipsch.

I also heard the AER FRs loaded with Oris at another friend's place and it was nice.

Thats why I am curious on how the Corals will perform on horns/waveguides...but they are of the ultra light type similar to the Fostex you have though...hmm..

The JBL mid waveguide posted earlier seemed quite interesting, and are found in JBL PRX535 @430Hz...I will get a pair..while I do have the SEOS 12 + Dayton D250 combo which could be put together as a three-way otherwise.