For other reasons, like I'm in an apartment. Don't want to be arrested.
But for other technical reasons like driver interaction with the adjoining MTM array. This is equal to one 15" per speaker, which is plenty for my needs and can distribute the bass better
Sony tubes must be only available in the EU
Sonotube. Auto-correction is a bitch.
Not backloaded, those use a straight frontloaded Electro Voice 15L 15" bass, down firing with a 40 hz flare. Front midrange drivers are 16 ohm coil jbl 2123j in parallel and a big neo magnet ribbon. Sensitivity is high, load is easy, Not too bad for direct radiation in the mid and treble - the fellow drove them with 45 SET amps, not sure what he uses with them now but they did replace his $10,000 speakers without a problem. Point is you can get great bass and midrange (the best i say) with a small footprint horn
So the thread comes back from suspended animation!
Anyway, to recap, I found that a 650 Hz crossover pushed the Radian 745Neo and the AH425 too hard; graininess started to intrude. Raising the crossover to 700 Hz cleared up the grain. Slightly higher (750 Hz) remains a possibility. If the horn were somewhat larger, 600 to 650 Hz would probably work ... with the lower limit set by the suspension of the Radian driver.
If a straight bass horn could cover the 50 Hz to 700 Hz range (without EQ) with dimensions of 29" wide and 24" deep, I'd use it. But the ones I've seen with those dimensions are pretty much gone at 100 Hz, and reaching as high as 700 Hz might involve a phase plug as well as EQ for the bass driver. Folding a bass horn allows more length, but then the upper bass response turns into a wrinkled mess, not at all suitable for a 700 Hz crossover.
I know the purist approach is a straight bass horn, but that would be a big horn several feet long, and an indicated crossover more in the 300 to 500 Hz region, which increases the size of the LeCleac'h mid-frequency horn from the 16.25"/413mm diameter of the AH425 to nearly twice that.
And now time-alignment problems crop up, with horns this long. Some folks like digital equalization and time correction, but I feel at that point you might as well build an all-solid-state multiway Linkwitz system, toss out the horns, and save a lot of space.
Anyway, to recap, I found that a 650 Hz crossover pushed the Radian 745Neo and the AH425 too hard; graininess started to intrude. Raising the crossover to 700 Hz cleared up the grain. Slightly higher (750 Hz) remains a possibility. If the horn were somewhat larger, 600 to 650 Hz would probably work ... with the lower limit set by the suspension of the Radian driver.
If a straight bass horn could cover the 50 Hz to 700 Hz range (without EQ) with dimensions of 29" wide and 24" deep, I'd use it. But the ones I've seen with those dimensions are pretty much gone at 100 Hz, and reaching as high as 700 Hz might involve a phase plug as well as EQ for the bass driver. Folding a bass horn allows more length, but then the upper bass response turns into a wrinkled mess, not at all suitable for a 700 Hz crossover.
I know the purist approach is a straight bass horn, but that would be a big horn several feet long, and an indicated crossover more in the 300 to 500 Hz region, which increases the size of the LeCleac'h mid-frequency horn from the 16.25"/413mm diameter of the AH425 to nearly twice that.
And now time-alignment problems crop up, with horns this long. Some folks like digital equalization and time correction, but I feel at that point you might as well build an all-solid-state multiway Linkwitz system, toss out the horns, and save a lot of space.
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Hello, Sure a bass horn can be built to that size and sound fantastic, I posted a picture of one. Crossing over above 500 is a problem but I think that is a compromise too if you can instead cover the 300 (or 500)to 3k range with a midrange horn. My point is two altecs in a reflex box is boring compared to a real horn loaded system and why not do it right if you are spending years designing/building it?
Altec 416 ca get low, but takes a BIG box. Current one is 9^ft+ and -3dB around 40-45 range with nice slow roll off. THis boz had been built and goes low, but is large in my room. A sealed box would allow smaller setup, that simple. There are many that would say a sealed box gives best transient response in bass region anyway.
http://www.diyaudio.com/forums/multi-way/91372-altec-lansing-95.html#post3535052
A late post. Somebody may have already answered this one. I have heard the change in the sound with change from class A operation to class AB.
The listening test was carried out using a transistor power amplifier based on a push pull design much like a Krell. This ran with typical audio power transistors with FT of 2 Mhz I listened through Quad ESL57 speakers. The set up allowed the bias current to be readily adjustable while listening to I guess at the time it was an orchestral LP Elgar or someting like that
It was very clear that as the transistors were biased to switch on say 0.6 volt the music was about 85dB the first sound to emerge was flat stereo with detail but sharpness (tranny noise). As the amp was biased up into full class A the sound transform into a deeper i.e fron to back depth into the recording venue. This happened early in the bias increase just aboe the 0.6 volts i.e class AB highcurrent bias. This was done on several occasions. I put it down to the switch on/off steps in the visible waveform. This is well documented in the literature some year ago. Higher FT transistors or rather faster switching transistors help but do not reduce this to inaudiblity. I now use my direct heated triode class A amp as my reference.
The listening test was carried out using a transistor power amplifier based on a push pull design much like a Krell. This ran with typical audio power transistors with FT of 2 Mhz I listened through Quad ESL57 speakers. The set up allowed the bias current to be readily adjustable while listening to I guess at the time it was an orchestral LP Elgar or someting like that
It was very clear that as the transistors were biased to switch on say 0.6 volt the music was about 85dB the first sound to emerge was flat stereo with detail but sharpness (tranny noise). As the amp was biased up into full class A the sound transform into a deeper i.e fron to back depth into the recording venue. This happened early in the bias increase just aboe the 0.6 volts i.e class AB highcurrent bias. This was done on several occasions. I put it down to the switch on/off steps in the visible waveform. This is well documented in the literature some year ago. Higher FT transistors or rather faster switching transistors help but do not reduce this to inaudiblity. I now use my direct heated triode class A amp as my reference.
See post 9155 by Lynn Olson for the cross section view and the associated posts for Q&A.
416-8B
Indeed. I have a a pair of 416's that do not measure at factory spec. Their greatest sin is that the Fs is much higher. Perhaps they have yet to be broken in (?) Purchased off e-bay from an A7 system barely used, or so had the details been reported.
None-the-less, I have a question: Would using one each of these drivers per side offer adaquate mid-bass duties for a high SPL system covering from approx 60hz up to about 500Hz, with 600Hz being the absloute highest I'd use them ?
If so, since a dedicated subwoofer system would be operating below, could a sealed enclosure be a better match than the classic vented often used with this driver?
And finally, (For Lynn) Could you supply an update on your speaker design since there have been so many pages devoted to this thread ?
( I guess that was actually 3 questions, not just 1)
Many thanks to all, for participating.
Indeed. I have a a pair of 416's that do not measure at factory spec. Their greatest sin is that the Fs is much higher. Perhaps they have yet to be broken in (?) Purchased off e-bay from an A7 system barely used, or so had the details been reported.
None-the-less, I have a question: Would using one each of these drivers per side offer adaquate mid-bass duties for a high SPL system covering from approx 60hz up to about 500Hz, with 600Hz being the absloute highest I'd use them ?
If so, since a dedicated subwoofer system would be operating below, could a sealed enclosure be a better match than the classic vented often used with this driver?
And finally, (For Lynn) Could you supply an update on your speaker design since there have been so many pages devoted to this thread ?
( I guess that was actually 3 questions, not just 1)
Many thanks to all, for participating.