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I will make the measurement , I'm courius to see if in my case the rear wall is responsible for the drop under 50Hz... In the meantime I've read your project, very interesting! And how you judge the sonic quality of the dsp? I prefer go passive because I've read some negative opinion about the sound of the dsp module but I've never heard one by myself...

I have a MiniDSP and an active XO (system is biamped). I used the MiniDSP to model the XO before building the active XO (Rod Elliot P09 kit). The FR has been measured in room and the P09 overlays the MiniDSP almost exactly.

Playing the TT there is a difference between the MiniDSP and P09. The P09 has greater depth and instrument separation in the image, it's not a lot but it's there.
 
Been experimenting with baffleless. These use Mark Audio Alpair 12p, XO at 250Hz to 2x Visaton W300 woofers in a W frame.

Removing the 12p baffle improved imaging but added a hole in the frequency response between 225-500Hz as the 12p rolls off naturally at 500Hz so the XO was changed back to the DSP and some EQ added as well as a cheap tweeter I had in the parts bin.

This change has me thinking now about engineering totally baffleless OB's including the woofer. The conclusion is even the small baffle of the 12p was colouring the sound.
 

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I have a MiniDSP and an active XO (system is biamped). I used the MiniDSP to model the XO before building the active XO (Rod Elliot P09 kit). The FR has been measured in room and the P09 overlays the MiniDSP almost exactly.

Playing the TT there is a difference between the MiniDSP and P09. The P09 has greater depth and instrument separation in the image, it's not a lot but it's there.
I also use a Minidsp 4x10. I was considering building an Elliot crossover but when I put a shunt regulator on the Minidsp the soundstage exploded.
Hugely greater depth and and space.
Maybe the biggest difference is the power supply you have used?
I am a fan of Rod Elliot all of my amps are tweaked 3A amps
Mark
 
The DSP is currently powered by the laptop. I'll have to dig out the wallwart I had. Do you use a linear supply for yours?
I used a shunt regulated linear power supply
All of my analogue low level equipment uses shunt regulators
The sound stage is much wider and deeper
The sound is detailed with the background noise being very low.
Little sounds appear in the background
This makes for a spatial sound
Good power supplies are everything:)
 
I have a MiniDSP and an active XO (system is biamped). I used the MiniDSP to model the XO before building the active XO (Rod Elliot P09 kit). The FR has been measured in room and the P09 overlays the MiniDSP almost exactly.

Playing the TT there is a difference between the MiniDSP and P09. The P09 has greater depth and instrument separation in the image, it's not a lot but it's there.
So the "analog sound processor" seems to be of better audio quality then miniDSP with poor power supply?
 
Been experimenting with baffleless. These use Mark Audio Alpair 12p, XO at 250Hz to 2x Visaton W300 woofers in a W frame.

Removing the 12p baffle improved imaging but added a hole in the frequency response between 225-500Hz as the 12p rolls off naturally at 500Hz so the XO was changed back to the DSP and some EQ added as well as a cheap tweeter I had in the parts bin.

This change has me thinking now about engineering totally baffleless OB's including the woofer. The conclusion is even the small baffle of the 12p was colouring the sound.
I've made a similir system, but with alpair 6P and 2 and then 4 visaton woofers WS 20 crossed at about 500Hz, but the 6P was too small to manage the power required for decent level without baffle and lack high frequency. Also the WS20 as no good power handling for low frequency, too much distortion, as so I've decide to invest for a definitive woofer (AE 15") and mid-tweeter (neo 8 and neo 3)...
Following an intermediate experiment with 4 visaton in quadrupole configuration:
visaton bg baffleless.jpg
 

adason

Member
Paid Member
2004-11-10 8:31 pm
Maryland
I've made a similir system, but with alpair 6P and 2 and then 4 visaton woofers WS 20 crossed at about 500Hz, but the 6P was too small to manage the power required for decent level without baffle and lack high frequency. Also the WS20 as no good power handling for low frequency, too much distortion, as so I've decide to invest for a definitive woofer (AE 15") and mid-tweeter (neo 8 and neo 3)...
Following an intermediate experiment with 4 visaton in quadrupole configuration:
View attachment 1005571
And there is no hidden subwoofer somewhere in the corner? Does it make clean 30Hz ?
What are the crossover frequencies for neo8 and neo3?
 
No, there isn't any hidden sub...infact they don't go as low as 30Hz! With 4 visaton I was able only to play music at moderate volume, otherwise the distorsion grows up very suddenly. The crossover was 800Hz for the visaton/neo8 and 7000Hz for the neo8/neo3.
Only with my last configuration with AE 15" dipole woofer I was able to play at higher volume and go down to 40Hz... :
nobaffle aebg front.jpg


Here are a measure I was made in my living room at 2m from the neo8:
spl 2m.jpg


The crossover has now a notch filter on the neo, but the notch is too much and not well centered on the neo's 12kHz peak! I have to refine the crossover, perhaps in the next days...
 
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A laptop USB output is not a bad power supply. A good quality laptop has a very clean USB 5v output. There is filtering and regulation.
Ok, so if you go baffle-less with your dsp, you can make a lot of tries in the crossover, what I cannot make in my system with passive crossover, maintaining a good quality... i think the baffle always makes diffraction, and degrade the stereo image. With baffle-less system, if well done, you can really make the drivers disappear.
 
Ok, so if you go baffle-less with your dsp, you can make a lot of tries in the crossover, what I cannot make in my system with passive crossover, maintaining a good quality... i think the baffle always makes diffraction, and degrade the stereo image. With baffle-less system, if well done, you can really make the drivers disappear.

Yes I agree, I heard a set of baffleless speakers a few weeks ago and the imaging was outstanding. The system I heard was a highly modded LP12 and the XO was DSP with EQ. Still it sounded awesome and has spurred me on to make baffleless speakers.

I use 2x Visaton W300 woofers per channel and these will be removed from the W frame to remove any potential reflections from the cabinets.

The DSP makes it easy to trial different XO frequencies and add some EQ. Although I try and EQ with driver choice and XO frequency, I am thinking this will not be possible with totally baffleless as the 300-500Hz band is very difficult to fill in without EQ.
 
Yes I agree, I heard a set of baffleless speakers a few weeks ago and the imaging was outstanding. The system I heard was a highly modded LP12 and the XO was DSP with EQ. Still it sounded awesome and has spurred me on to make baffleless speakers.

I use 2x Visaton W300 woofers per channel and these will be removed from the W frame to remove any potential reflections from the cabinets.

The DSP makes it easy to trial different XO frequencies and add some EQ. Although I try and EQ with driver choice and XO frequency, I am thinking this will not be possible with totally baffleless as the 300-500Hz band is very difficult to fill in without EQ.
I have infact the same issue with baffleless midrange: initially I'll try to cross them very low, about 300Hz, but with no good result: too much distortion at normal listening level. So I decide to cross them at 800Hz, where the lack of the baffle begin to appears, but for that reason is mandatory to have a good midrange from the woofer, that's why I decide to go for AE 15" woofers, they have a very very good mid range with very low distortion. I use them up to 1,5kHz and they sound absolutely good.
 
I heard a set of baffleless OB's a few weeks ago and they were stunning. Consisting of a ribbon tweeter and 4 x each side 6.5" mid woofers. XO is 2800Hz and 150Hz to subwoofer. The additional 6.5" drivers gave enough SPL to XO at a low 150Hz to the sub. 2 shelf filters were needed to get the FR flat, which was easily done in the DSP crossover.

The smaller 6.5"'s providing the upper bass meant the lower midrange/upper bass response had great attack.

Hearing these is what sent me on a quest to improve my speakers.
 
Here are a measure I was made in my living room at 2m from the neo8:
View attachment 1005762

The crossover has now a notch filter on the neo, but the notch is too much and not well centered on the neo's 12kHz peak! I have to refine the crossover, perhaps in the next days...
I am interested in details of this measurement. How much power did the AE15 need to make this SPL. What crossover are you using for AE 15" to the Neo 8
This measurement,
 

adason

Member
Paid Member
2004-11-10 8:31 pm
Maryland
No, there isn't any hidden sub...infact they don't go as low as 30Hz! With 4 visaton I was able only to play music at moderate volume, otherwise the distorsion grows up very suddenly. The crossover was 800Hz for the visaton/neo8 and 7000Hz for the neo8/neo3.
Only with my last configuration with AE 15" dipole woofer I was able to play at higher volume and go down to 40Hz... :
View attachment 1005761

Here are a measure I was made in my living room at 2m from the neo8:
View attachment 1005762

The crossover has now a notch filter on the neo, but the notch is too much and not well centered on the neo's 12kHz peak! I have to refine the crossover, perhaps in the next days...
Thanks for info.
I do have 4way open baffle in the main system now with two 15" woofers going up to 150Hz, then 8" betsy to 900Hz, then 8" slim planar to 3" planar. Lots of similarities.