-6dB @ 104Hz for 2 pi steradians (floor loading only - aka half space)
-6dB @ 95Hz for pi steradians (floor and wall loading - aka quarter space)
When playing music the slow roll off between 200Hz and 104Hz would be difficult if not impossible to detect by ear. The only way you would ever know it is if you played test tones at both frequencies. I also suspect the roll off will not be as much as predicted due to the mouth being larger than required for half space loading. The mouth is large enough for 107Hz in half space alone. If the horn mouth is within 5 and a half feet of a wall, it will get additional spatial loading which would fill in the 200Hz to 104Hz range nicely. If the roll off really bothers you then you can reduce the rear chamber volume to push the resonance up and scarifice some of the bottom end. A 6.5 liter back chamber will raise the -6dB point to 108Hz, but will level out the roll off. I still believe the predicted roll off is more than what it will be in real life.
Attachments
S1 to S2 accounts for the parabolic expansion of the paraline. S2 to S3 is the exponential horn shell attached to the paraline
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JLH,
I'm fascinated by this design.
I have a pair of Faital M5N12 here - and am considering building a 140hz version for them. Could be nice and compact.
What would you esimate the in-real-life upper roll off to be?
thanks
I'm fascinated by this design.
I have a pair of Faital M5N12 here - and am considering building a 140hz version for them. Could be nice and compact.
What would you esimate the in-real-life upper roll off to be?
thanks
The practical lower limit for the M5N12 is about 150Hz. Use 11mm or 12mm thick material for the Paraline. If everything is perfect the math suggests to top end to be about 760Hz. However, I would not bank on that. While it very well could go that high, I don't know what it would sound like. Probably best to not to go higher than 600Hz.
I have not personally listened to the Faital FD371. I have listened to the B&C DE35, Beyma CP-22, Selenium ST300, Selenium ST350, Eminence APT-80, Fostex T90A, and Fostex T925. All of them are pretty good. I think the best bang for the buck would be the Selenium ST350. The B&C and Beyma are solid long time stand ins. If you want to spend extra money the Fostex tweeters are nice, but do not have any mounting provisions. Regardless, to me all these newer tweeters sound and perform better than the old vintage super tweeters. Our technology has come a long way since the 50's.
I don't know. I would have to sit down with a specific set of goals and design for it. Sometimes I can throw out a quick educated guess, but to answer your question would require quite a few calculations.
Parts Express sold out of the 12PE32 again - LOL
Went ahead and put it on back order. Can't do much more until I actually get one in hand. Time to play the waiting game.
Went ahead and put it on back order. Can't do much more until I actually get one in hand. Time to play the waiting game.
I had a go around with CelectronicUSA with some Faital HF104 drivers. I won't be doing that again. I actually ended up getting the HF104 drivers from MCM Electronics of all places. I only deal with Parts Express, US Speakers, Loudspeakers Plus, or MCM Electronics.
B&C 12PE32 12" Low Frequency Driver
I ordered once from them and all was smooth. Here in Canada now, I use qcomponents.ca for B&C drivers.
I ordered once from them and all was smooth. Here in Canada now, I use qcomponents.ca for B&C drivers.
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