Dear Ivica.
Sorry I forgot to reply to your post #104.
Please note I am - opposite you - a non-educated sales person.. I am NOT an electronic or an acoustic engineer, or even not an skilled speaker designer + builder. All I am doing is based on "common sense" thinking, and I picked-up just a little knowledge (experience) here and there during the last two decades by reading and listening. When I wan't something done such as developing the electronic controllers for my "EX", I pay an engineer to do it, based on my notes from listening test and simple measuring.. Off course this has a been heavy and time consuming job to me, but since there are no "ready to buy LF solution" for the E2, I did the best I could. I should really love to audition a system similar to mine but fine-tuned by GT and his team.. wow!
As you can read in my above post, my large listening room calls for LF extension. When designing my system I used an Digital "Voicing" Eq from Accuphase (DG-38), and the read out at the display told me 30Hz from DD66000 in my listening position and 10-12 different mic. positions on and off-axis was minus 6-9 dB from linear (zero), and to the sound I preferred minus 12-15dB.
My goal was flat response to 30Hz but compared to preferred sound I ended up needing additional 6-9dB from 40 down to 30Hz on top of "flat" before getting satisfied..? Hopefully you know what I mean. Measuring looks crazy (loudness on..), but it sounds "right". This is why I am talking about the non linearity of human hearing must be the reason to my wish for additional 6-9dB gain at 30-40Hz. I know human hearing flattens out when going loud.. but I can't express my self in this discussion due to my limited english langue skills. Sorry.
Regarding your comments about the impossibility into design and build a speaker thats linear to 20Hz, using 18" LF + a very low cross over point by passive components, some kind of adjustment will be needed, etc; you are right.
Also I will make Widget and 4313B happy by confirming one important thing; At some music (natural instrumentation), I'll never (or very very seldom) need my LF-EXtensions. But at much electronic music I can't live without LF Extension + boost.
And the core thing in construction my system is not building the big boxes with the dual 18" pr. channel, but developing the "brains" - the dual mono 3 way electronic crossovers/eq's I got designed especially to my system.
They are very very important since music material changes from one record to another = flexibility are needed. I designed an 3-option solution:
E2 full-range with EXtension's "Off", a 45 and a 60Hz cross-over point. (24/24dB/octave).
Further more a 4-position (0,3,6,9dB) boost option at 28Hz (Fs of my 18" woofers), with a narrow Q (0,7), since I don't want the "loudness" type of sound from lets say a Q 2.0
Finally I got a 0 to +6dB variable volume at LF out-put (but NO volumes/attenuator at MF + HF out in order to avoid this in signal chain).
Via the Accuphase DG-38 I measured a notch from 700 to 800Hz, and decided to move cross-over point from 750 to 800Hz in order to boost the Al1501-1 +2dB safely against the 4" Be. I changed slopes (the passive internal filter setting = 12/18dB at 750Hz) to 800Hz 24/24dB to further protection of the 4" Be as I am adding a 1+2 dB boost option from 700-800Hz as compensation to the AL1501-1
Via the Accuphase I also measured an 1- 1,5 dB peak at around 5kHz and added a 1-2dB notch-option at 5kHz, and finally a 3-6dB boost option at 20kHz as i measured a 3-6dB drop from the 1" Be vs. the 4" Be.
(All of those EQ's can be passed through).
I think it is very obvious that any LF system intended for use with the E2 is some kind based on a variable electronic crossover + EQ controller in order to adjust LF to the specific listening room, and in my particular situation it was also obvious to go all-in by making a 3 way crossover as I noticed the E2 benefits a lot when upgrading from passive to electronic crossing over between 15" and 4".
2269H: It is no secret thats my dream woofer! But the local JBL pro distributer is asking $2200/each spare part price = my total driver cost ? $8800…... Pretty insane! US JBL PRO-retailer Northern Sound and Light made me an offer at ASB-7128 (dual 2269H) for $3350/box. Thats telling me the drivers shouldn't cost more than 1000-1200$/each. Sponsor wanted
, or perhaps I go for the AE (Acoustic Elegance) TD18H+ ($450) as they have gained a pretty nice reputation.
Kind regards
Henrik,
DynaMax
www.dynamax.dk