John and his Wave Guide
OK....
Have recieved the wave guides and the SB Acoustic tweets... and put together a simple prototype.
First impressions are postitive... doing some A - B comparisions between the old 3800 and new wave guide configuration.
Need to get through break in and start resolving cross over issues... the wave guide does elevate the midrange as it extends the low end cut off potential.... so have to flatten the response out to achieve something usably flat... and provide the correct roll off to properly mate with the Peerless 12". This will take some time. Hope I can shape the response to replicate what the 3800 provides with out having to resort to too many crossover tricks...parts. Stay tuned....
OK....
Have recieved the wave guides and the SB Acoustic tweets... and put together a simple prototype.
First impressions are postitive... doing some A - B comparisions between the old 3800 and new wave guide configuration.
Need to get through break in and start resolving cross over issues... the wave guide does elevate the midrange as it extends the low end cut off potential.... so have to flatten the response out to achieve something usably flat... and provide the correct roll off to properly mate with the Peerless 12". This will take some time. Hope I can shape the response to replicate what the 3800 provides with out having to resort to too many crossover tricks...parts. Stay tuned....
Good news !
The NEO3-W (*without* DPR extension) performs even better in dipole horn
Parts-Express.com: Bohlender Graebener Neo3W Planar Tweeter w/Back Cup | neo3 planar tweeter ribbon tweeter planar transducer
Got the second set of speakers today. Here is a comparison:
we see that efficiency is ~ 4-5dB up (compared to the NEO3 *with* DPRW extension) I have shown earlier in
http://www.diyaudio.com/forums/multi-way/110583-fast-fun-inexpensive-ob-project-3.html#post1996193
- and also overall FR smoothness and polar smoothness in the horn is way better:
I bought the second pair as I wasn't really satisfied with my first measurements of the NEO3 * DPRW* but didn't know if its from my quasi min phase horn or from the NEO3.
There still is some polar wiggle in the 2.5kHz region but even that one is slightly smoother now.
So - room for improvement and tweaking of that NEO3-W.
Michael
The NEO3-W (*without* DPR extension) performs even better in dipole horn
Parts-Express.com: Bohlender Graebener Neo3W Planar Tweeter w/Back Cup | neo3 planar tweeter ribbon tweeter planar transducer
Got the second set of speakers today. Here is a comparison:
we see that efficiency is ~ 4-5dB up (compared to the NEO3 *with* DPRW extension) I have shown earlier in
http://www.diyaudio.com/forums/multi-way/110583-fast-fun-inexpensive-ob-project-3.html#post1996193
- and also overall FR smoothness and polar smoothness in the horn is way better:
I bought the second pair as I wasn't really satisfied with my first measurements of the NEO3 * DPRW* but didn't know if its from my quasi min phase horn or from the NEO3.
There still is some polar wiggle in the 2.5kHz region but even that one is slightly smoother now.
So - room for improvement and tweaking of that NEO3-W.
Michael
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Excellent research Michael,
Thank you for your hard work on the "Min Phase Dipole Horn", quite impressive. Any chance you've measured distortion on the Neo3? Wonder what a Neo8 in your "Min Phase Dipole Horn" under the Neo3 would sound and measure like.
Finally, not to further complicate your build, do you think your dipole horn would improve if it's top and bottom had flares (a 60-90 degree angle)?
Craig
Thank you for your hard work on the "Min Phase Dipole Horn", quite impressive. Any chance you've measured distortion on the Neo3? Wonder what a Neo8 in your "Min Phase Dipole Horn" under the Neo3 would sound and measure like.
Finally, not to further complicate your build, do you think your dipole horn would improve if it's top and bottom had flares (a 60-90 degree angle)?
Craig
Thanks, yes I'm gonna measure distortion "some time"– but actually I'm more interested in "Back Diaphragm Mirror Distortion"....
Audio and Loudspeaker Design Guide Lines
as I think *this* will make up for a major sonic difference / improvement for the NEO3 in dipole operation (versus monopole operation).
I haven't tried (nor tried to simulated what would be possible) and don't have that lot experience with horns to answer such a question seriously.
My rough guess would be no – as you basically change vertical directivity towards a conical horn of "some arbitrary" behaviour.
Michael
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Excellent research Michael,
Thank you for your hard work on the "Min Phase Dipole Horn", quite impressive. Any chance you've measured distortion on the Neo3? Wonder what a Neo8 in your "Min Phase Dipole Horn" under the Neo3 would sound and measure like.
Finally, not to further complicate your build, do you think your dipole horn would improve if it's top and bottom had flares (a 60-90 degree angle)?
Craig
According to Zaph's measurements (non dipole) the Neo3 has very low distortion and that is how I subjectively experience them too.
Zaph|Audio
Zaph|Audio
Hi Jonasz,According to Zaph's measurements (non dipole) the Neo3 has very low distortion and that is how I subjectively experience them too.
Zaph|Audio
Zaph|Audio
I've also enjoyed the Neo3 PDR in one of my Arvos projects. I should have worded my question better; how low can this open back Neo3 in a"Min Phase Dipole Horn" be crossed before distortion becomes an issue? BTW, did you ever adjust to Arizona?
If only I was better with tin snips...
Craig
Hi Craig,
well, we lived there for a year but now we're back in Sweden again. I still dream of moving there sometime in the future, especially now in the wintertime when there's hardly any sunlight here... The weather is definately better in AZ!
I'm also interested in the same question as yourself so I guess we'll just have to wait and see what Michael comes up with. However looking at Zaph's measurements it looks like there's at least some potential!
well, we lived there for a year but now we're back in Sweden again. I still dream of moving there sometime in the future, especially now in the wintertime when there's hardly any sunlight here...
The weather is definately better in AZ! I'm also interested in the same question as yourself so I guess we'll just have to wait and see what Michael comes up with. However looking at Zaph's measurements it looks like there's at least some potential!
Hi Michael,
Vertical Dispersion and Polar Response Measurements
Does your Min Phase Dipole Horn with the NEO3 have a limited vertical dispersion which makes the treble go away when you stand up?
Is there a listening distance where the frequency response is uniform for someone standing up?
Is there a mathematical equation for this horn profile to help assure the best accuracy? I want to experiment cutting your horn profile out of insulating foam with a hot wire.
Thanks.
Vertical Dispersion and Polar Response Measurements
Does your Min Phase Dipole Horn with the NEO3 have a limited vertical dispersion which makes the treble go away when you stand up?
Is there a listening distance where the frequency response is uniform for someone standing up?
Is there a mathematical equation for this horn profile to help assure the best accuracy? I want to experiment cutting your horn profile out of insulating foam with a hot wire.
Thanks.
Maybe the new Dayton RS silktweeter can be a good match for this speaker, though not dipole. They make this gutsy statement.
Parts-Express.com:*Dayton RS28F-4 1-1/8" Silk Dome Tweeter | Dayton Audio RS28F-4 1-1/8" tweeter Silk Dome reference series mtm d'appolito dr.k usher hf high frequency driver
Parts-Express.com:*Dayton RS28F-4 1-1/8" Silk Dome Tweeter | Dayton Audio RS28F-4 1-1/8" tweeter Silk Dome reference series mtm d'appolito dr.k usher hf high frequency driver
Second horn got ready so I'd like to spend a little bit of time on a passive XO .
A question or two for the passionate passive-XO cooks here:
I have only two iron core 6,8mH (0.27 Ohm) which I used in series for one speaker.
So now - has anybody tried to what MisterTwister suggested in
http://www.diyaudio.com/forums/multi-way/110583-fast-fun-inexpensive-ob-project-2.html#post1662619
??
I mean – we lose a little bit of SPL in the upper department of the 12" as the impedance rise there is flattened out when I shunt the speaker to get same roll off frequency with the smaller inductor.
Or should I add a small inductor in series to the 12" to compensate?
#######
Anybody who can show FR of the original XO for each speaker separately?
#######
Pano – can you show FR for the modified XO for the SS3805 (each speaker separately)?
http://www.diyaudio.com/forums/multi-way/110583-fast-fun-inexpensive-ob-project-3.html#post1869737
Michael
A question or two for the passionate passive-XO cooks here:
I have only two iron core 6,8mH (0.27 Ohm) which I used in series for one speaker.
So now - has anybody tried to what MisterTwister suggested in
http://www.diyaudio.com/forums/multi-way/110583-fast-fun-inexpensive-ob-project-2.html#post1662619
??
I mean – we lose a little bit of SPL in the upper department of the 12" as the impedance rise there is flattened out when I shunt the speaker to get same roll off frequency with the smaller inductor.
Or should I add a small inductor in series to the 12" to compensate?
#######
Anybody who can show FR of the original XO for each speaker separately?
#######
Pano – can you show FR for the modified XO for the SS3805 (each speaker separately)?
http://www.diyaudio.com/forums/multi-way/110583-fast-fun-inexpensive-ob-project-3.html#post1869737
Michael
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First hurdle solved:
all measurements at zero mic distance!
The middle trace shows the FR with two 6,8mH = ~13mH in series with the 12" (being the reference of the original XO)
The upper trace shows FR with just one 6,8mH in series (obviously not enough roll off - like expected)
The lower trace shows FR with 6,8mH and a 7.5 Ohm across voice coil. (too much roll off in the higher department due to *less* impedance rise there)
The *second* middle trace shows above with a 1.2mH in series with the 7.5 Ohm shunt (not much to improve I'd say...)
Would appreciate if some could post FR @ 1m though
Michael
all measurements at zero mic distance!
The middle trace shows the FR with two 6,8mH = ~13mH in series with the 12" (being the reference of the original XO)
The upper trace shows FR with just one 6,8mH in series (obviously not enough roll off - like expected)
The lower trace shows FR with 6,8mH and a 7.5 Ohm across voice coil. (too much roll off in the higher department due to *less* impedance rise there)
The *second* middle trace shows above with a 1.2mH in series with the 7.5 Ohm shunt (not much to improve I'd say...)
Would appreciate if some could post FR @ 1m though
Michael
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Hi,
I made a fast test with a resistor in parallel with the woofer I didn't like the treble. There is something wrong.
Simulation with my measurement 1m/4ms gate . You should also see my post about my version
Original crossover from my baffle
raw measurement
Hope this helps.
I made a fast test with a resistor in parallel with the woofer I didn't like the treble. There is something wrong.
Simulation with my measurement 1m/4ms gate . You should also see my post about my version
Original crossover from my baffle
An externally hosted image should be here but it was not working when we last tested it.
raw measurement
An externally hosted image should be here but it was not working when we last tested it.
Hope this helps.
Hi Jerome, thanks for fast answer -
yes a single resistor in parallel with the woofer is too much off - as I expected and have measured above.
Now with the cute little trick to add a "small" inductor to compensate for loss of speaker impedance rise it seems I can emulate any effective inductance I need.
My guess would be low pass is pretty close to the original XO now
What I concentrate on is to get high pass for the NEO dipole horn right at the moment.
What would you suggest for this?
Michael
yes a single resistor in parallel with the woofer is too much off - as I expected and have measured above.
Now with the cute little trick to add a "small" inductor to compensate for loss of speaker impedance rise it seems I can emulate any effective inductance I need.
My guess would be low pass is pretty close to the original XO now
What I concentrate on is to get high pass for the NEO dipole horn right at the moment.
What would you suggest for this?
Michael
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Seems I have to measure impedance of the NEO3 in horn first as I always get severe wiggles in the XO area that ain't there without XO - or use the VC shunt trick a second time...
(NEO3 impedance is already pretty low )
Your 4th order high pass in sum and difference looks gorgeous - I just haven't the guts to go that complex...
Michael
(NEO3 impedance is already pretty low
)Your 4th order high pass in sum and difference looks gorgeous - I just haven't the guts to go that complex...
Michael
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A second order crossover for the tweeter like on the original manzanita should be sufficient if you use my woofer crossover with the RLC trap.
Perhaps it could work only with a capacitor on the Neo3 and an inductor on the woofer.
Hey Michael. Sorry, no measurements from me at the moment. I took my Manzantia apart.
But I did try the trick with parallel resistor earlier this year. Although my simulation software showed that it worked well, I did not like the sound of it. Like Jerome. Don't remember what now, but it did not work as well....
But I did try the trick with parallel resistor earlier this year. Although my simulation software showed that it worked well, I did not like the sound of it. Like Jerome. Don't remember what now, but it did not work as well....
That tweeter looks very interesting. We don't know how much distortion it has down low, but it should be worth a listen. I think John has this tweeter, I'll ask him.
Which reminds me, I did find a pair of the little 2" Aurasound drivers. Need to send those to John