Ultimate Low Frequency Extension

Mark Seaton said:

I'd be curious if the designers of your preamp and amplifiers don't think they could integrate a simple high pass filter without significantly compromising the performance. The passive networks needed to create the filtering at speaker level, while still fully analog, have their own limits of linearity, interact significantly with the speaker's load, and will even change their interaction with big dynamics. For many systems, the best high pass filter is the acoustic one created by an appropriately sized sealed box... Which I suspect is the way your MM7's operate.

To be clear, I'm largely agnostic on the methods of executing a crossover... so long as it works in an objective manner and a desirable result is had.

Click to expand...

well.....actually......the darTZeel NHB-18NS does, in fact, have the facility to power a low frequency circuit. it has provisions for tri-amping each with it's own preamp output. according to the provisional manual, all three outputs are separately buffered, and optional built in filters can be activated for bi-amping or tri-amping purposes. I don't use mine that way myself as my speaker system, the EA MM7's, provide the bass towers the signal from the speaker terminal of the main towers so the purity to the main tower is not compromised. and when the signal is taken from the speaker terminal, the character of the main amp is carried through to the bottom octave amplification. using a separate crossover upstream of the main amp, you have to then work to get a consistent amplifier character.

this picture shows the back of the old version of the preamp; the -3- BNC outputs in the bottom right (BNC 50 ohm darT outputs) are the same on the new version. it would be cool to tri-amp using 3 sets of 458's.

interesting theme
I have an all out DIY hi eff horn system with 112db/2,83v from 75-22K
initially I used a custom 4x15" custom reflex system from Bert Doppenberg in NL made for my AG Trio system
however it was only after I got my hi-eff hornloaded 21" 18sound sub, that I grasped the importance of a properly designed subsystem
it´s a custom job by fellow Norwegian Rune Skramstad a world renowned authority on hornsubs
4 meter frontloaded vented back chamber design
92db@20Hz
100db@30Hz
total capacity 135db continuous @30Hz
this gives you an ease of presentation and even on low volume the sub frequencies are just present, cruising along
my entire horn system changed character with the new subs
they are actively lopassed @75Hz and driven by selfbuild Tower of Power Holton 800 monoblocks

christensenleif@msn.com said:

interesting theme
I have an all out DIY hi eff horn system with 112db/2,83v from 75-22K !!!!!!
initially I used a custom 4x15" custom reflex system from Bert Doppenberg in NL made for my AG Trio system
however it was only after I got my hi-eff hornloaded 21" 18sound sub, that I grasped the importance of a properly designed subsystem
it´s a custom job by fellow Norwegian Rune Skramstad a world renowned authority on hornsubs
4 meter frontloaded vented back chamber design
92db@20Hz
100db@30Hz
total capacity 135db continuous @30Hz !!!!!!
this gives you an ease of presentation and even on low volume the sub frequencies are just present, cruising along
my entire horn system changed character with the new subs
they are actively lopassed @75Hz and driven by selfbuild Tower of Power Holton 800 monoblocks
<sniP>

Click to expand...

Wow! A system I would love to hear

Clean bass reproduction brings a lot more to the reproduction than just bass.. Clarity throughout the audible spectrum ... Whatever the musical genre.

Btw the line signal is from a parallell output on my TVC. The signal to the 300b s driving the stack from 75 and up is unaffected. The fullrange parallell output goes to the 24db/oct 75hz active lopass subfilter. The sub horn are time aligned with the midbasshorns and are less than 14millisec delayed which at theese low frequencies aree of no consequence
Best
Leif

christensenleif@msn.com said:

interesting theme
I have an all out DIY hi eff horn system with 112db/2,83v from 75-22K...a custom job by fellow Norwegian Rune Skramstad a world renowned authority on hornsubs
4 meter frontloaded vented back chamber design
92db@20Hz
100db@30Hz
total capacity 135db continuous @30Hz
this gives you an ease of presentation and even on low volume the sub frequencies are just present, cruising along
my entire horn system changed character with the new subs
they are actively lopassed @75Hz and driven by selfbuild Tower of Power Holton 800 monoblocks

Click to expand...

fantastic...few subs can generate that kind of db at that level under any circumstances. And yes, ease of presentation is a huge part of all-out assault in my experience. The big Wilsons were the first taste for me relative to all others in my own personal experience. Since then, i have gone on to hear the big Genesis, Rockports and earlier Tidal Sunray 4-towers as well. Not heard full-range, big horns which would be great to hear.

I have active ATCs which start to drop off at around 30Hz, then an ATC C6 sub continues on to around 20Hz. To reinforce the lower frequencies I have an infinite baffle sub built into the ceiling. This comprises of a manifold, extending into the loft space, containing 2 x 18 inch IB specific drivers also driven actively. this takes the useful response below 20Hz.

It took some time to integrate the subs but the combined effect now produces clean, undistorted, powerful, bass to below 20Hz. plus excellent ambient retrieval and imaging even at lower volumes.

This is a REW measurement taken at the listening position 1/3 smoothing.