The response of the midTweeter would be modulated by the bass waveforms that form in the enclosure. The bass driver will likely be little influenced by the midTweteer, except that being a thin paper cone, likely to act as an unintended frictional vent in the cabinet, shortcircuiting the line and decreasing the line’s performance.
It is unlikely to work out. But if you are placing a sealed cup over the midTweeter, it can be done after you verify that not having it is not a good idea.
A small box up in the corner like that will have little effect on the line performance. A bit more HF might escape out the terminus, but given the low XO, unlikely to be an issue.
dave
It is unlikely to work out. But if you are placing a sealed cup over the midTweeter, it can be done after you verify that not having it is not a good idea.
A small box up in the corner like that will have little effect on the line performance. A bit more HF might escape out the terminus, but given the low XO, unlikely to be an issue.
dave
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What kind of volume does the Fostex need in this approach, assuming the XO goes somewhere around 400Hz to 500Hz ? And how sensitive is the idea volume to the choice of XO?
What advantage to allowing it to vent out the back?
What advantage to allowing it to vent out the back?
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1 litre. Even a bit smaller given the high XO.
A TL out the back — it would impede the line, gives a low pressure enclosure where you have enuff length to try to completely suppress the back wave. The larger TL will not go as low but can be made to roll off quite slowly (a droopier response).
dave
A TL out the back — it would impede the line, gives a low pressure enclosure where you have enuff length to try to completely suppress the back wave. The larger TL will not go as low but can be made to roll off quite slowly (a droopier response).
dave
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1 litre seems very reasonable to me.
A couple more thoughts were coming to mind as I was looking for other use cases on the web.
One was baffle edge diffraction, the concept of the supra baffle (?) as a means to improve the imaging performance of the stereo pair. I can imagine there being a strong connection between edge diffraction and the quality of imaging. There isn’t an obvious way to add such a thing to my PMC but it maybe an interesting experiment. And I’ve seen others use sound absorbing felt on the front baffle as another method to supress edge diffraction artifacts. As my PMC has a speaker grill this might be an option although the Fostex itself seems to require a fair bit of space in front of it.
Another idea was that of assuming the existing PMC tweeter play the role of super tweeter to the Fostex which adopts the role of a mid. Perhaps a simple cap only on the tweeter to bring it in at around 10kHz. Then the Fostex is put into it’s own box and located on top of the PMC to make a woofer-tweeter-mid. For c to c spacing the XO point for the woofer-Fostex would want pushing down further. This configuration is not something I’ve yet seen on a FAST but I have seen it on one of Troel’s 3-ways.
A couple more thoughts were coming to mind as I was looking for other use cases on the web.
One was baffle edge diffraction, the concept of the supra baffle (?) as a means to improve the imaging performance of the stereo pair. I can imagine there being a strong connection between edge diffraction and the quality of imaging. There isn’t an obvious way to add such a thing to my PMC but it maybe an interesting experiment. And I’ve seen others use sound absorbing felt on the front baffle as another method to supress edge diffraction artifacts. As my PMC has a speaker grill this might be an option although the Fostex itself seems to require a fair bit of space in front of it.
Another idea was that of assuming the existing PMC tweeter play the role of super tweeter to the Fostex which adopts the role of a mid. Perhaps a simple cap only on the tweeter to bring it in at around 10kHz. Then the Fostex is put into it’s own box and located on top of the PMC to make a woofer-tweeter-mid. For c to c spacing the XO point for the woofer-Fostex would want pushing down further. This configuration is not something I’ve yet seen on a FAST but I have seen it on one of Troel’s 3-ways.
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A speaker having a low diffraction signature is an important aid in improving image/soundstage.
Re your first picture, an elispse base form will work better than a circle.
dave
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Joined 2009
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Thanks Dave.
I am looking into the details.
The Scan Speak 10F/4424G00 is another candidate I have 're-discovered' and the physical mounting is very close to the existing tweeter so that there would be little need for butchery.
It's an interesting comparison to make, between the Fostex and the Scan Speak, at least 'on paper'. The Scan Speak was not around in the hey day of the Fostex. Are modern wide band drivers like the 10F responsible for the decline in visibility of the FE108ES on this forum ?
From reading around I sense that the 10F, being the more modern and technically up to date driver, is more accurate and with fewer h.f. anomalies. But the Fostex has subjective qualities that are missing from the 10F.
I am looking into the details.
The Scan Speak 10F/4424G00 is another candidate I have 're-discovered' and the physical mounting is very close to the existing tweeter so that there would be little need for butchery.
It's an interesting comparison to make, between the Fostex and the Scan Speak, at least 'on paper'. The Scan Speak was not around in the hey day of the Fostex. Are modern wide band drivers like the 10F responsible for the decline in visibility of the FE108ES on this forum ?
From reading around I sense that the 10F, being the more modern and technically up to date driver, is more accurate and with fewer h.f. anomalies. But the Fostex has subjective qualities that are missing from the 10F.
The Scan is good. Not near as sensitive, and not as seductive, but probably more accurate.
Also to consider if you are looking at other 3” is the Mark Audio Aplair 5.2/3 or Fostex FF85wk. Also the larger Alpair 6.2m (if you can find any — i have some).
dave
Also to consider if you are looking at other 3” is the Mark Audio Aplair 5.2/3 or Fostex FF85wk. Also the larger Alpair 6.2m (if you can find any — i have some).
dave
Fostex likes limited version.
Qts 0.39 of fe108e∑ is what I wanted to listen.
But the price...
https://www.fostex.jp/products/fe108ss-hp/
Qts 0.39 of fe108e∑ is what I wanted to listen.
But the price...
https://www.fostex.jp/products/fe108ss-hp/
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