I don't know how familiar you are with JBL's but I have a couple of their direct radiator systems that I have also cloned over the years. That would be the XPL-200A and the L250TI Jubilee. I have always used direct radiators as at least one of the references I use when cloning systems.
I have heard some coloration in the 2307 horn used in my 4344's and in the 2344 horns used in the 4430/4435 when pushed hard. Looking at your response curve why don't you give up some efficiency and roll the lower end of the horn a bit. You have quite a bit of HF "loss".
Rob
The subject of colouration of sound which always comes up in these threads is a fascinating thing. Unless you spend most of your time listening to live, totally unamplified music I don't really think anybody has any idea what is coloured.
Even where active equalisation is done in concert halls the sound is no longer üncoloured" I would have thought.
When you do go to a live concert, amplified or not, one of the real joys is the emotion of the music. If the music can be reproduced in your home to give you the same or similar sense of emotionally being part then, whatever the type of system or whatever the colouration, would I think be pretty irrelevant. Very high efficiency speakers including horns are particularly good at this.
Maybe talk along these lines could be the subject of its own thread or has it already been thrashed out to the death somewhere?
jamikl
Even where active equalisation is done in concert halls the sound is no longer üncoloured" I would have thought.
When you do go to a live concert, amplified or not, one of the real joys is the emotion of the music. If the music can be reproduced in your home to give you the same or similar sense of emotionally being part then, whatever the type of system or whatever the colouration, would I think be pretty irrelevant. Very high efficiency speakers including horns are particularly good at this.
Maybe talk along these lines could be the subject of its own thread or has it already been thrashed out to the death somewhere?
jamikl
Geddes and Le Cleac'h have it right. Check out the 16 horns compared experiment.
Smooth rounded walls, no parallel walls, no corners, no pinching in the throat, no sudden breaks in the horn wall path, those all help to make an excellent sounding horn (least reflections, better waterfall response).
I'd like to try the stereo lab horns (400hz one crossed 24db LR at 600hz), but I don't think I could live with the lack of directivity past 5khz of that tractrix.
Paul Klipsch preferred tractrix over exponential, but many others prefer conical over tractrix.
I'd think a conical could have the least coloration (except for maybe at the throat) if you wrap the mouth in foam. I think wrapping a horn mouth would even improve a horn that flares into the baffle, catching reflections from lighting up the edges of the baffle (even with a roundover).
I've never pushed frequencies below the horn's loading (couldn't say). And I like the idea of some open cell foam in the throat, but I havn't played with that either.
Check out these sites too.
Building Oblate Spheroid Waveguides Far and away the most difficult project I've done to date. Article By Jeff Poth
Acoustic Horn - Conical Horn Geometry
Norman
Smooth rounded walls, no parallel walls, no corners, no pinching in the throat, no sudden breaks in the horn wall path, those all help to make an excellent sounding horn (least reflections, better waterfall response).
I'd like to try the stereo lab horns (400hz one crossed 24db LR at 600hz), but I don't think I could live with the lack of directivity past 5khz of that tractrix.
Paul Klipsch preferred tractrix over exponential, but many others prefer conical over tractrix.
I'd think a conical could have the least coloration (except for maybe at the throat) if you wrap the mouth in foam. I think wrapping a horn mouth would even improve a horn that flares into the baffle, catching reflections from lighting up the edges of the baffle (even with a roundover).
An externally hosted image should be here but it was not working when we last tested it.
I've never pushed frequencies below the horn's loading (couldn't say). And I like the idea of some open cell foam in the throat, but I havn't played with that either.
Check out these sites too.
Building Oblate Spheroid Waveguides Far and away the most difficult project I've done to date. Article By Jeff Poth
Acoustic Horn - Conical Horn Geometry
Norman
My horns are all that........
I have used 1,8khz first order in my last test, with Fc of the midrange horn ~ 500hz.......
One of the issues in comparing drivers of different types: ribbons, horns, dynamic is that they have rather different polar responses. This means a different interaction with the room that can not be ignored. The possible exception is if you have a room about the size of a small barn, where the Rt is long enough to make the reflection come back late enough so as to not effect the perception of the direct sound. Almost no one has such a room. (I want one)
It is true that all drivers and speakers have some sort of "signature" that we can discern. There is no perfect driver (yet), so we're looking to pick and choose amongst the assorted list of benefits and deficits. Of course the game is to minimize the deficits and pick those (if you can) that are the least objectionable. It's a cosmic balancing and juggling act, isn't it?
_-_-bear
(I want one)It is true that all drivers and speakers have some sort of "signature" that we can discern. There is no perfect driver (yet), so we're looking to pick and choose amongst the assorted list of benefits and deficits. Of course the game is to minimize the deficits and pick those (if you can) that are the least objectionable. It's a cosmic balancing and juggling act, isn't it?
_-_-bear
"One of the issues in comparing drivers of different types: ribbons, horns, dynamic is that they have rather different polar responses."
Take a look at the differences between the on axis measurement of the ribbon and the on axis measurement of the horn system as linked in the 2nd or third post. The measurement is a 1/3 octave RTA with a 60db widow. There looks to be a 10-20 db drop in the upper octaves above 1K. The ribbon is essentially flat out to 20k. Looking at the measurements no wonder the horn sound all midrange.
Rob
Take a look at the differences between the on axis measurement of the ribbon and the on axis measurement of the horn system as linked in the 2nd or third post. The measurement is a 1/3 octave RTA with a 60db widow. There looks to be a 10-20 db drop in the upper octaves above 1K. The ribbon is essentially flat out to 20k. Looking at the measurements no wonder the horn sound all midrange.
Rob
Maybe I missed it, but how did no one else comment on this? The frequency response varies approximately 10dB from midbass to upper midrange to treble. Of course the sound is colored! Forget cabinet materials, amplification, etc. You need something approaching a smooth frequency response (even if not exactly flat) before you go chasing any of that other stuff. Looking at the polar response to make sure that changes smoothly as well, especially through the crossover region, would be the next thing I'd check.
Ha! I feel the same way about bass drivers! I'm in the process of building a sub with an 18" 95dB driver.
What about using some kind of sound absorbing material on the inside surfaces of the MF and HF horns? (foam, etc) Should the inside surfaces of these horns be shiny or rough? Bruce Edgar recommended shag carpeting for lower frequency horns... <g>
Last edited:
Yeah, and the HF rolloff is maybe affecting a lot of the sound of the system also?
I was speaking in general terms.
The specific speaker system, Angelo's, has assorted issues... one of the concerns I have is (even with flat output from the tweeter horn) is that is is shaded by the other horns, causing reflections and diffractions due to its placement. (ignoring the freq resp issue...)
I am also concerned about the midbass horn's driver...
The size of the HF horn WRT freq of interest.
And, as previous mentioned, the potential for IM and THD from too low a slope xover for the midrange compression driver on the low side... one option there is to go for a low slope near the xover point, and then drop the lower freqs out inside the amp itself, or before the amp...
What we learn from all this is that horns are not a panacea, nor are any other ways to make speakers - they all have issues that need to be dealt with and overcome.
Agree with this, and I'd expand it to say that while horns gain you some things (directivity control and higher efficiency), they make many other things about designing a speaker much more difficult. You are almost guaranteed to have a non-flat response to deal with and you have drivers with narrow bandwidths and steep rolloffs at the extremes of their bandwidth. This means simple text book crossovers will almost never work, and it's much more difficult to design an appropriate crossover.
But then I don't listen to PA's outdoors because the horns drive me nuts - and I'm to cheap to pay the cover charge to get into the clubs!!!! Well - that and the fact that the bands don't really get cooking until well past my bed time.
Thomas,
Tell the truth now, it's not really past your bedtime, they just throw you out for being unruly.
You keep forgetting that you're no longer a 21 year old sailor! Those were the days.
Best Regards,
Terry
John - not "almost guaranteed" you are guaranteed that if the device is CD then it cannot have a flat far field response. Its physics. If you see a horn that has a flat response (anywhere) and is not EQ'd then it cannot be CD.
Yes, the crossovers are very difficult to design, it's not "cookbook" by any means. It's the poor crossovers that I see used on a lot of horns that has given them a bad reputation. Horns and waveguides are not for the novice, but their advantages cannot be ignored if you know what you are doing.
I hate that term: "CD".
Nominated for worst audio term ever.
Now do you mean "Constant Dispersion" or do you mean "Constant Directivity"?
And what exactly is "constant" about either?
And how do you know which one someone is talking about?? Talk about two non intutively clear terms...
_-_-bear
Nominated for worst audio term ever.
Now do you mean "Constant Dispersion" or do you mean "Constant Directivity"?
And what exactly is "constant" about either?
And how do you know which one someone is talking about?? Talk about two non intutively clear terms...
_-_-bear
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.