Hi Magnetar, good questions.
The axial hole is small greatly diminshed at 7.5 degrees, and totally gone at 15 degrees. In theory I suppose it could contribute to some image shift for some off-centerline listeners, but it's high enough up that it's in the overtone region.
I use a Beyma, as that came out a bit smoother in the waveguide I use. I think that Earl tried the Beyma but preferred the B&C.
I don't use a Gedlee waveguide because the DDS is available off-the-shelf, ready-to-use (after a little grinding) with no development costs. I have not licensed Earl's refractive foam insert; for one thing I give higher priority to WAF than Earl does. I think the foam insert makes more of a difference at high SPLs than at low ones. If someone really wants it, I'll contact Earl about it.
The Dream Makers are a fullrange bipole; there's a second waveguide on the back along with that second woofer. This certainly does depart from what Earl is doing, but the imaging localization cues come from the front-facing drivers.
Because of my limited room height (and limited ability to lift the speakers!), I can only generate good time-gated data down to 900 Hz or so.
The DDS plots are similar to those of the XT120 in the horizontal plane, except if anything they track one another even more closely (same vertical separation at low end as at high end of the spectrum) from 7.5 degrees to 90 degrees.
Panomaniac, thank you! I wanted people to know that, in this area at least, my speakers offer a useful look at what Earl's design does. I appreciate your thumbs-up very much.
Duke
The axial hole is small greatly diminshed at 7.5 degrees, and totally gone at 15 degrees. In theory I suppose it could contribute to some image shift for some off-centerline listeners, but it's high enough up that it's in the overtone region.
I use a Beyma, as that came out a bit smoother in the waveguide I use. I think that Earl tried the Beyma but preferred the B&C.
I don't use a Gedlee waveguide because the DDS is available off-the-shelf, ready-to-use (after a little grinding) with no development costs. I have not licensed Earl's refractive foam insert; for one thing I give higher priority to WAF than Earl does. I think the foam insert makes more of a difference at high SPLs than at low ones. If someone really wants it, I'll contact Earl about it.
The Dream Makers are a fullrange bipole; there's a second waveguide on the back along with that second woofer. This certainly does depart from what Earl is doing, but the imaging localization cues come from the front-facing drivers.
Because of my limited room height (and limited ability to lift the speakers!), I can only generate good time-gated data down to 900 Hz or so.
The DDS plots are similar to those of the XT120 in the horizontal plane, except if anything they track one another even more closely (same vertical separation at low end as at high end of the spectrum) from 7.5 degrees to 90 degrees.
Panomaniac, thank you! I wanted people to know that, in this area at least, my speakers offer a useful look at what Earl's design does. I appreciate your thumbs-up very much.
Duke
"Forgot about a request earlier for impulse responses. I have those and I will post them. "
Thanks I can import them into Clio so can Zilchlab.
Rob🙂
Thanks I can import them into Clio so can Zilchlab.
Rob🙂
gedlee said:
audiokinesis said:
Dr. Geddes,
First and foremost thanks for your measurements. Interpretation and potential subjective bias aside (hard to avoid those I guess...but afterall we're all human 🙂) that was hard factual data you provided, and I would like to thank you for that.
Did you have the chance / any plans for evaluating the DDS waveguide Duke is employing (I am guessing it's the ENG 1-90, right Duke ?). Similar/same conditions for comparative purposes would help a lot.
Again, thanks (in advance) for the data.
Regards,
Florian
I try and be helpful 🙂
No I have not evaluated the DDS unit and doing this kind of thing for free is just not something that I can consider doing right now. I would be glad to take this data for anything on an hourly rate basis.
I don't think that I gave any subjective opinions on that horn at all, only that based on what I measured I would not use it.
No I have not evaluated the DDS unit and doing this kind of thing for free is just not something that I can consider doing right now. I would be glad to take this data for anything on an hourly rate basis.
I don't think that I gave any subjective opinions on that horn at all, only that based on what I measured I would not use it.
FlorianO said:
What's wrong with the manufactures plot? It doesn't have the Gedlee dip! Neither does my round tractrix horns - these probably sound excellent with a good driver like the Beyma Duke uses.
"Clio can read a txt file? Or what format do you want."
Hello Earl
It has an import data function but I have used it once a while back. I have to get back to you on what it can import. May be Zilchlabs or another will jump in here?? It exports text files it would make sense it should be able to import them. You would think.
Thanks Rob🙂
Hello Earl
It has an import data function but I have used it once a while back. I have to get back to you on what it can import. May be Zilchlabs or another will jump in here?? It exports text files it would make sense it should be able to import them. You would think.
Thanks Rob🙂
audiokinesis said:
Thanks Duke, looks like you building an innovative speaker.. two horns - front and back?!? - Ever wire it all up as a dipole? Or maybe just the top end?
Does the DDS load the Beyma well down to 900 like they claim? Subjective or objective opinions or facts are all fine by me.
Magnetar said:
DAH! Thats because they are all normalized to be 0 dB on axis! (Why do I even respond to these comments 🙄
gedlee said:
DAH! Thats because they are all normalized to be 0 dB on axis! (Why do I even respond to these comments)
No they aren't LOL
Magnetar said:
Your saying that this horn is perfectly flat with no, I repeat, no, not even +- 1 dB response on axis.
No not at all - I said they aren't normalized to the zero axis as you stated
Maybe we have our jingo skewed?
If you were 'normalize" your horn to the zero axis you state it won't work - I agree - but the DDS of course will work normalized to your axis because they are more constant directivity then yours
Maybe we have our jingo skewed?
If you were 'normalize" your horn to the zero axis you state it won't work - I agree - but the DDS of course will work normalized to your axis because they are more constant directivity then yours
Magnetar said:
Yeah, those look very groovy! Might have to get a pair of the XT1086. Looks like they may bolt up to my Altec drivers without too much fuss.
Magnatar. You say that your round Tractrix has good on/off axis response, right? My 8 sided ones sure don't. The highs beam down the middle like crazy. How do you prevent that?
Hmm, the impulse looks like some high frequency percussion type instruments are going to sound a bit funny. I would certainly like to get to listen to a pair to get a better feeling.FrankWW said:
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