Hi, I'm new to the forum. I've been toying with the thought of building a set of OB loudspeakers. I've got a set of magnaplanar SMGa's that I've always loved because of the wide open soundstage and their sweet detail. They're well balanced because I use them in conjunction with a Klipsch passive sub that fills in the low end nicely. Their main drawback to me is they have too much of a laid-back sound and don't offer the real punch and dynamics that I'd like. I understand why they have such a broad soundstage because they radiate out the back of the loudspeaker as well as the front.
What my question is, is what advantage is there to horns used in an open baffle configuration when horns don't radiate sound out the back of the loudspeaker? Do horns in an OB offer any improvement in soundstage over being mounted in an enclosure, and if so, how? Does the OB design contribute to a broad, open soundstage that extends to outboard of the loudspeakers even with horns, is that just a virtue of the OB design? Thanks for your patience and for any and all explanations. I've enjoyed reading the threads in this forum and there are a lot of very knowledgeable folks here. I haven't been able to find the answers to my questions with a search though. Thanks!
What my question is, is what advantage is there to horns used in an open baffle configuration when horns don't radiate sound out the back of the loudspeaker? Do horns in an OB offer any improvement in soundstage over being mounted in an enclosure, and if so, how? Does the OB design contribute to a broad, open soundstage that extends to outboard of the loudspeakers even with horns, is that just a virtue of the OB design? Thanks for your patience and for any and all explanations. I've enjoyed reading the threads in this forum and there are a lot of very knowledgeable folks here. I haven't been able to find the answers to my questions with a search though. Thanks!
I could be wrong, but,
If it's a horn then it can't be an Open Baffle.
As I understand it OB radiate from both sides of the drivers cone.
If one side is closed (horn) then it cannot be an OB.
However you could make a dipole horn. (guessing here)
Would need a second horn for the rear part of the 'dipole'.
Hope thats right......
Last time I heard the mag's, they were good, but, as you say they have limited dynamics.
And as for 'sweet spot' listening, don't even move a few cm's out..
If it's a horn then it can't be an Open Baffle.
As I understand it OB radiate from both sides of the drivers cone.
If one side is closed (horn) then it cannot be an OB.
However you could make a dipole horn. (guessing here)
Would need a second horn for the rear part of the 'dipole'.
Hope thats right......
Last time I heard the mag's, they were good, but, as you say they have limited dynamics.
And as for 'sweet spot' listening, don't even move a few cm's out..
"If one side is closed (horn)" - if a horn would be closed, that would be a bad thing, since no sound would radiate out of it. he probably means a horn with no back chamber, which should behave similar to an ob in the low frequencies, which are not affected by the horn anymore and a bit more complicated in the mid and high frequencies.
as for the wide soundstage you mention, i think this is an (maybe pleasing) artefact from the rear radiation of an OB. this artefact will only be interesting in the mid and high frequencies above the modal range of your room. linkwitz raved about adding a rear tweeter to his ob some time ago, so that may be a good thing if you like that sound.
it boils down to what kind of sound you like. controlled directivity, "headhone sound" in the attempt to recreate the original room information of the recording by minimizing the influence of your room or omnipolar and bipolar radiation to place the recording in your room via maximum reflections. of course those are the extremes, everything else is in between.
since a horn is a device to controll directivity, i think its counterintuitive to make it open in the rear, since that will swamp your lovely controlled front directivity with alot of late reflections coming from the rear walls. but maybe you like that sound
as for the wide soundstage you mention, i think this is an (maybe pleasing) artefact from the rear radiation of an OB. this artefact will only be interesting in the mid and high frequencies above the modal range of your room. linkwitz raved about adding a rear tweeter to his ob some time ago, so that may be a good thing if you like that sound.
it boils down to what kind of sound you like. controlled directivity, "headhone sound" in the attempt to recreate the original room information of the recording by minimizing the influence of your room or omnipolar and bipolar radiation to place the recording in your room via maximum reflections. of course those are the extremes, everything else is in between.
since a horn is a device to controll directivity, i think its counterintuitive to make it open in the rear, since that will swamp your lovely controlled front directivity with alot of late reflections coming from the rear walls. but maybe you like that sound
EV made a dipolar horn driver. Paul Eizik has a large dipolar horn system with horns pointing front and rear wired in opposite polarity.
Not the same as open baffles of course.
Funny thing about open baffles; very few people will admit to making a bad one. Only Kurt Chang and me as far as I know.
Not the same as open baffles of course.
Funny thing about open baffles; very few people will admit to making a bad one. Only Kurt Chang and me as far as I know.
Soundlab made a HUGE front and back horn loaded electrostat, like eight feet fall and six feet deep - a local guy has a pair. Sound good, but still sound like toys compared to a good dynamic horn loaded system. Very cohesive but still has the poor dynamics of other electrostats.
TOM- I have heard plenty of bad sounding open baffles, almost as many as bad sounding horns.
TOM- I have heard plenty of bad sounding open baffles, almost as many as bad sounding horns.
critterxl said:
Was your question really about an OB horn or a horn integrated into an OB like mine?
Here's My Usher/Altec Horn Loaded Open Baffles...
I like your setup! Thanks for posting the pics. That's more or less what I had in mind with mounting my horns except I was not planning on using them in conjunction with conventional drivers, horns only along with my separate sub. I guess what my question really was, was whether or not to expect any of the really broad soundstage usually associated with OBs with the horns since the horns don't radiate out the back like more conventional drivers- Thanks for your replies and ideas guys-
If you really love the sound of your current speakers, and just want to up the punch then have you considered doing some sort of midbass 15" / 18" array OB to run next to the old speakers ? Cross them in around 250 - 300 Hz and you'll get more in the punch region plus the original sound you love.
Maybe there's reasons this won't work (I'm not really up on OB theory) but whenever I see someone who is happy with their current sound, but wants more punch I automatically think 'add a dedicated midbass'
Rob.
Maybe there's reasons this won't work (I'm not really up on OB theory) but whenever I see someone who is happy with their current sound, but wants more punch I automatically think 'add a dedicated midbass'
Rob.
Hmm, even with no rear cap on a compression driver, I don't think that would be considered OB for the simple fact that the driver still has a load against it due to the horn itself, right?
Also, if you're running your compression driver at a somewhat low-ish xover point, wouldn't not having the rear cap on it cause the driver to reach and/or exceed its Xmax prematurely?
Please correct me if I'm wrong about any of this.
Also, if you're running your compression driver at a somewhat low-ish xover point, wouldn't not having the rear cap on it cause the driver to reach and/or exceed its Xmax prematurely?
Please correct me if I'm wrong about any of this.
chops said:
i would guess, since a closed volume behind the membrane acts like a acoustical highpass filter, those guys exchange it for an electrical or digital one. playing at low volume may also help. i also would guess that is done to lower the f3 of the compression driver for playing it to deeper frequencies in a hifi low spl setting. instead of this, one could use a coaxial compression driver from bms or a unity style horn, both offering lower distortion.
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