I hope there will be some ‘good sharing‘ of the award 😉 Im planning to press buy on multiple baskets…
Hi Anand,
I have noticed that every now and again someone brings up active crossovers in this thread but it does not go anywhere. In every example that I can recall the person making the request is asked to try it out and post results but this does not seem to happen. The general thought on active crossover for this project is that the sound can not match the analog XO. This could be because of the skill level of the active crossover "programmer" but again I can't recall any posted results with success. The problem with active crossovers in this project is lack of feedback from the driver to the crossover components. The active crossover can not determine what the electrical characteristics of the driver are at any given time / frequency. Analog components can because they are in the same circuit. Also consider that listening environments are so different that the miniDSP would need lots of tweaking just for your situation.
But again please try it out and let the community know.
I for one would love a solution that did not require so much inductor cost and waiting because of our current supply problems.
Have fun with the project and keep searching around the forums as there are many masterfull active crossover users.
I have noticed that every now and again someone brings up active crossovers in this thread but it does not go anywhere. In every example that I can recall the person making the request is asked to try it out and post results but this does not seem to happen. The general thought on active crossover for this project is that the sound can not match the analog XO. This could be because of the skill level of the active crossover "programmer" but again I can't recall any posted results with success. The problem with active crossovers in this project is lack of feedback from the driver to the crossover components. The active crossover can not determine what the electrical characteristics of the driver are at any given time / frequency. Analog components can because they are in the same circuit. Also consider that listening environments are so different that the miniDSP would need lots of tweaking just for your situation.
But again please try it out and let the community know.
I for one would love a solution that did not require so much inductor cost and waiting because of our current supply problems.
Have fun with the project and keep searching around the forums as there are many masterfull active crossover users.
I haven't had much luck with active and this design, but if you have the gear, why not give it a try? I'd try a 60Hz low pass first order on the woofer. On the Vifa tweeter try a first order circa 750Hz. Yes, that far apart. Bring the tweeter level down about 3dB. Once you have that in place, add a 6dB/octave shelf filter at 1000Hz attenuation ~3dB.
You can play with the level of the shelf and the tweeter to find what works. Placing a 1/2 ohm resistor in series with the woofer will partly imitate the effect of the big 20mH coil in series.
Sorry that I don't have an exact active formula for you, but with active it's easy to experiment. Let us know what you find. But honestly, the passive is so simple it's hard to beat. The main stumbling block is the big inductor - where to find one and at what price.
After a 4 day holyday back in Vienna and today I changed the placement. The speakers are now 1.2 m in front of the wall (about 3.1 ft) instead of 0.7 m and it is a huge improvement. There is even much more room, much more and deeper stage, the instruments are not tied to the speakers anymore, there is much more liveliness and dynamics. The bass improves further, now it is deep and punchy and I think after some more time it will be even "better".
I will listen with this setting for a while and will observe the mids. It's just me, but I think I must brake the mid section (I am very sensitive in this area) but at the same time I will allow more (louder) treble. I even think about to build a new baffle and use baltic birch instead of MDF.
So, I am extremely excited and know where the way goes.
I will listen with this setting for a while and will observe the mids. It's just me, but I think I must brake the mid section (I am very sensitive in this area) but at the same time I will allow more (louder) treble. I even think about to build a new baffle and use baltic birch instead of MDF.
So, I am extremely excited and know where the way goes.
Is there a considered opinion on the baffle material. A full sheet of 18mm MDF is about £30 locally, whereas BB is £100. I thought MDF would be easier (you know cheaper to mess up) where as BB will need less finishing. I’d even thought about laminating two pieces so make the driver cutouts bigger on the back piece. The downside of MDF is it being filthy to work with.
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The reason the analogue crossover may sound better may be down to the fact that the main driver has appreciable inductance, and this will vary with cone excursion. If the driver is voltage-fed, as would be the case for a dsp crossover, this would give rise to variations in voicecoil current as a result, and therefore significant harmonic and intermodulation distortion. However, if fed via a (large) inductor (as prescribed), voicecoil current would vary far less - so distortion would be signifcantly lower.
Just to lighten the mood on this fine day I want to show you my mini manzi. I am using this to get my OB fix while waiting for Manzanita parts. The mini is paired with a sealed velodyne. I think the setup should be called Manzi-Pedi. At any rate there is only a cap on the tweeter and the rest is done with Dennon AVR-1802 80Hz highpass and APO-EQ.
The drivers are fosters from a 70's console. They are being moved from a 9.5 by 17.5 to a 17.5 by 22.75 baffle. These speakers sound just good enough to have me hooked on OB for my folk , bluegrass and vocal listening. Cant wait till I have an OB worthy of Rock, Orchestral and Big Band.
I cant tell a difference at all.
Thanks
Jeremy
The drivers are fosters from a 70's console. They are being moved from a 9.5 by 17.5 to a 17.5 by 22.75 baffle. These speakers sound just good enough to have me hooked on OB for my folk , bluegrass and vocal listening. Cant wait till I have an OB worthy of Rock, Orchestral and Big Band.
I cant tell a difference at all.
Thanks
Jeremy
Well, it's well known that that Le varies with excursion, and that this would cause distortion at higher frequencies if voltage fed. It's also obvious (?), that current drive (approximated by the large series inductor at high frequencies) would get round this.
What isn't clear is how audible the HD and IMD due to this source might be - but it's an obvious candidate for the differences experienced by Pano etc.
If you must, there's part of the story illustrated here:
https://www.researchgate.net/figure...er-vs-position-in-the-airgap-x_fig4_228757382
Not that I'm necessarily an advocate of "current drive", as it's inferior when Bl varies with excursion (and certainly inferior at coping with resonances).
https://www.researchgate.net/figure...er-vs-position-in-the-airgap-x_fig4_228757382
Not that I'm necessarily an advocate of "current drive", as it's inferior when Bl varies with excursion (and certainly inferior at coping with resonances).
Yep, some pretty tedious threads on current drive. But I would expect Le(x) to be mainly about IMD rather than HD (as large excursions won't usually be occurring at higher frequencies).
But, to get back to the point, you surely aren't denying the likelihood that Le(x) could be causing Pano's observation that "inductive drive" sounds better than active EQ/crossover?