Shouldn't we already be using active XO's seeing as they give better performance? A class D amp could even be used for the LF unit .
I had a little look at some FR drivers and I think the sort of driver I'm trying to describe would be one similar to the Fostex FX120. Very flat frequency response, and good dispersion in the high frequencies.
I had a little look at some FR drivers and I think the sort of driver I'm trying to describe would be one similar to the Fostex FX120. Very flat frequency response, and good dispersion in the high frequencies.
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Shouldn't we already be using active XO's seeing as they give better performance?
It is nice to bi-amp. That doesn't need an active XO, it can be done passively, but realistically 1st order is most practical, but that takes advantage of the close proximity (less than 1/4 wl at XO) to achieve good time response. Higher order takes that off the table.
dave
Yeah, I was thinking of using the FAST driver to go from 300 to 30 instead of the FX120 which would only go down to about 70 or so without an XO.
Just wondering if there are benefits in terms of distortion performance when using FAST or is it just the bass response that is improved?
Just wondering if there are benefits in terms of distortion performance when using FAST or is it just the bass response that is improved?
If you consider an FX120 appropriate please look at response of 5MR450NDY. I think FX120 costs more and may not be as sensitive. Smoothness of response is about same and high end on both is circa 15kHz? High passing at 300Hz doesn't change break up - that is function of cones resonant modes and mechanics at high freq excitation. If you XO at 300Hz there is no advantage that the FX120 will give you bass wise, as it would have if going full range in a BLH for example.
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A whole thread on it with data. The variations in response appear similar in amplitude to FX120.
http://www.diyaudio.com/forums/full-range/259293-prv-5mr450-ndy-fast-applications.html
Also sound clips in that thread with it XO at 350Hz.
More measurements here too:
http://www.diyaudio.com/forums/full...nd-comparison-3in-5in-full-range-drivers.html
http://www.diyaudio.com/forums/full-range/259293-prv-5mr450-ndy-fast-applications.html
Also sound clips in that thread with it XO at 350Hz.
More measurements here too:
http://www.diyaudio.com/forums/full...nd-comparison-3in-5in-full-range-drivers.html
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wondering if there are benefits in terms of distortion performance when using FAST or is it just the bass response that is improved?
Yes. And bass performace is improved.
dave
Yes. And bass performace is improved.
dave
Reducing Doppler distortions, through high passing a full ranger cleans up the sound a lot.
But is an active 4th order crossover not 0* phase at the speaker?
Or is it 360* phase, affecting the timing?
But is an active 4th order crossover not 0* phase at the speaker?
Or is it 360* phase, affecting the timing?
It is 360°
On top of that there is just something wrong with LR4
dave
Dave, could you tell me what's wrong with LR4 ?
Seems to me that most fullrange speakers could be improved with FAST if that is the case with Doppler (FM distortion if I'm right?).
It also appears to me that the Fostex FX120 is probably the best bet for a FAST system. I was originally looking at building an Alpair 12P BR but having looked at it's frequency response graph and realising the scale was twice as much as I originally thought it was I was a little put off this .
Seems to me that most fullrange speakers could be improved with FAST if that is the case with Doppler (FM distortion if I'm right?).
It also appears to me that the Fostex FX120 is probably the best bet for a FAST system. I was originally looking at building an Alpair 12P BR but having looked at it's frequency response graph and realising the scale was twice as much as I originally thought it was I was a little put off this .
could you tell me what's wrong with LR4?
I just don't like how they sound. I am not alone.
Seems to me that most fullrange speakers could be improved with FAST if that is the case with Doppler.
Yes
It also appears to me that the Fostex FX120 is probably the best bet for a FAST system.
Good but i would not consider it best. Personally of the Fostex i prefer the FF85wk.
dave
It also appears to me that the Fostex FX120 is probably the best bet for a FAST system.
Certainly the best looking.
jeff
Dave, could you tell me what's wrong with LR4 ?
Steen Duelund had this to say about the LR4:
Steen Duelund in his paper said:With this value the bandpass fades away and you get a 2-way 4th order filter.
It is well known as the Linkwitz Riley solution (squared Butterworth).
The Q-value is 0.707 and will give ringing in the step response. This is heard as a focussing on the instrument(s), minimising the recorded sound from the surroundings.
That let to him to design his own filter schematic, using a filler driver to get rid of the ringing. More in his paper: http://www.diyaudio.com/forums/full-range/273524-10f-8424-rs225-8-fast-ref-monitor-12.html#post4318945
Not a solution for fast, but an interesting view on LR4.
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