Oh yes, theres a reason why the most difficult xo point of a 3way is between woofer and midrange
All whats below 1khz defines the quality of the rest, much more than the other way round
Compression drivers
If you look at all the bigger drivers you will see that they all tend to be rough
And most big compressio drivers doesnt really go much lower
They are mostly made to just play louder, and take more power
Im sure they could design it just to get lower, but its not in the card fore pro sound
And there will be other drawbacks like the need fore steep filters, to avoid substantial raise in distortion
May not be a problem with aktive systems, but will be fore passive
Maybe one day the pro designers will begin to see a small market in hifi, and make better driver fore this
Sacrifice high SPL fore highest quality
Im sure they could, if they wanted to
Could seem like they are beginning to look more at quality
Might be due to many bands use smaller and smaller gear, every year
Even "PinkFloyd" sounds better when small
May have started with the first "unplugged" concerts
Was Nirvana first ?
And even recording studios may use non pro drivers
Im sure pro manufactorers fight to keep alive
And in the future they can only survive on best quality
Earl, how about it, will we ever see a plain stereo Geddes Special DIY Audiocom 3way
All whats below 1khz defines the quality of the rest, much more than the other way round
Compression drivers
If you look at all the bigger drivers you will see that they all tend to be rough
And most big compressio drivers doesnt really go much lower
They are mostly made to just play louder, and take more power
Im sure they could design it just to get lower, but its not in the card fore pro sound
And there will be other drawbacks like the need fore steep filters, to avoid substantial raise in distortion
May not be a problem with aktive systems, but will be fore passive
Maybe one day the pro designers will begin to see a small market in hifi, and make better driver fore this
Sacrifice high SPL fore highest quality
Im sure they could, if they wanted to
Could seem like they are beginning to look more at quality
Might be due to many bands use smaller and smaller gear, every year
Even "PinkFloyd" sounds better when small
May have started with the first "unplugged" concerts
Was Nirvana first ?
And even recording studios may use non pro drivers
Im sure pro manufactorers fight to keep alive
And in the future they can only survive on best quality
Earl, how about it, will we ever see a plain stereo Geddes Special DIY Audiocom 3way
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Earl, how about it, will we ever see a plain stereo Geddes Special DIY Audiocom 3way
If you exclude the subs, no not at all likely as I have studied the problem intensly and see no alternatives.
No, not a scientific paper. IIRC the last thing I read was Earl saying in one of his threads that imaging cues are strongest at 2 kHz.
I didn't mean to say there is no localization <1 kHz, just that it lessens and the lion's share of the benefit is above.
Noah
Similar to the localization of natural sound sources, the localization of phantom sound sources below and above 1000-1500 Hz is dominated by either time differences or differences in intensity. One needs to preserve those cues regardless of their type or frequency.
The frequency range which is influenced by reflections (Toole):
Best, Markus
Similar to the localization of natural sound sources, the localization of phantom sound sources below and above 1000-1500 Hz is dominated by either time differences or differences in intensity. One needs to preserve those cues regardless of their type or frequency.
The frequency range which is influenced by reflections (Toole):
An externally hosted image should be here but it was not working when we last tested it.
Best, Markus
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Why is 500Hz-1kHz being discounted? the beamwidth is tapering in this region in the Summa, so it does somewhat address the desirability for limited dispersion in this region. It would be undesirable to jump from omni to 90at the XO, the smooth transition takes place with a woofer. One could do a wide-angle tractrix and use the bandwidth tapering like that of the woofer, if one wanted to control dispersion I suppose.
It would be desirable to have a narrower directivity down to 500 Hz and to widen below that - its just not feasible.
But reality always seems to wedge its way in there somewhere.
I COULD do it, I have the space, but based upon my experinces with the four sizes that I make, there is a significant diminishing returns with larger speakers. And I would NEVER do anything that would require another crossover point above 2 kHz. I have said before anjd I will say again - crossovers are evil and should be avoided to the maximum extent possible. I would never add one for; greater output or headroom; narrower directivity; lower frequency directivity control; or just about anything else that I can think of at the moment. The negative of another crossover far far outweighs any of the positives that I can see in these other options.
Would a cardioid enclosure, leaking from the sides, be a feasible trick to introduce directivity at lower frequencies? If its doable, it would just require careful design, but not much added cost. And maybe one more reason to buy the design from you rather than trying to design a waveguide speaker by oneself...
Like the RL901K from ME-Geithain?
See http://www.me-geithain.com/en/download/rl901keng.pdf
Directivity:
Free field:
Best, Markus
See http://www.me-geithain.com/en/download/rl901keng.pdf
Directivity:
An externally hosted image should be here but it was not working when we last tested it.
Free field:
An externally hosted image should be here but it was not working when we last tested it.
Best, Markus
I had that idea years ago, but could not make it work within the "practical" limits that I think necessary. What could be done, and this is in my book in case you think I just made it up, is to use a second woofer on the back and to control the directivity with the amplitude and phase of the second one. To do a passive cardiod is impossible, of course, and a single source cardiod is difficult to get the bandwidth wide enough to use all the way up to the waveguide. But with a second driver on the back this is no problem. Still it doubles the box volume and would probably be a good $1000 - $2000 increase in cost. NOT the right direction on those two parameters.
Oops. I meant, NOT very large. As in, the three or four people who want such a thing and have the space and means to effect it have probably already designed it or commissioned it themselves.
Earl, a couple of questions about Harper surrounds:
1. How do you suggest handling the bottom end? Looks like there is roll off below 150 Hz so that it's 12 db down at 80 Hz.
2. What angle is best towards the listener? Is there a problem with them pointing directly at the listener?
3. Is it worth angling the surround a little
I also notice that the Nathan has a smaller axial hole than the Abbey. Is this related to the waveguide itself, or have you managed to better optimise the Nathan crossover so far?
1. How do you suggest handling the bottom end? Looks like there is roll off below 150 Hz so that it's 12 db down at 80 Hz.
2. What angle is best towards the listener? Is there a problem with them pointing directly at the listener?
3. Is it worth angling the surround a little
I also notice that the Nathan has a smaller axial hole than the Abbey. Is this related to the waveguide itself, or have you managed to better optimise the Nathan crossover so far?
Hi Paul
Good questions:
1) I use subs and set the surrounds to "small" this moves all LFfor the surounds to the subs.
2) I've played with this in simulations and it all depends on how close ther are to a ceiling and if it is reflective or not. If they are close to a reflective ceiling then they work best facing straight out parrallel to the ceiling, otherwise aim them down slightly towards the farthest listener on the other side of the room.
3) I understand the axial holes - they are caused by diffraction at the mouth. But there is a subtle effect of the actual mouth radius and the null frequency. It appears that this hole is aggravated when there can be a resonance across the mouth at the same frequency as the hole. The hole depends on one set of coordinates and the resonance another. If they coincide, as they do in the Abbey, then the hole is worsened, if not then its better. So a slightly smaller or larger mouth on the Abbey might be a good idea. I'd like to make a system with a 12" woofer and a 15" waveguide - I think that this would be ideal. (But then I'd like to do a lot of things.)
1) Earl, that's how I would do it with the surrounds but I'm concerned about the gap. In my case it's between 80 Hz and 150 Hz. Are you saying that this doesn't matter, or that the subs should run up to 150 Hz? I did some simulations and it seems it can get to 80 Hz with a vented design, but this appears to be forcing the driver lower than it was designed for.
2) What about the horizontal angle?
2) What about the horizontal angle?
My subs all pretty much go up to 150 Hz and in film the LFE channel goes up that high. Remember I don't "cross over" to subs. Everything overlaps. Trickier to set-up but it works great.
I should have mentioned, that I would turn the Harpers on their side if near the ceiling. If not then vertical and pointed as stated -straight across the room.
Why do you say that? Most low Q pro drivers are intended to be ported.
I just finished some surrounds using the B&C 8CX21, which I believe is the same woofer, and get (according to Unibox and WinISD) -3dB@90 Hz in a ported 9 liter box tuned to 75 Hz.
I used a single 2" port, which at first looks to give too high a velocity, but is fine when the HP filter is added.
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