To: Todd White, Dave Fitts, Dwight ST, ckp, & Cal Weldon the A6A gang.

[Manta-Ray]

One and all:

I confess to being as dumb as a sack of hammers....

To each and every one of you I say... However infinitesimal you feel your knowledge of "acoustics" is...it seems like Mount Everest to me. I am a farmer. My mom dragged me to the symphony when I was a kid. I like my music to sound "real"...and as "live" as it can possibly be. I think they call it "presence".
The first pair of speakers I could afford were JBL-166's...as good as they were...they couldn't hold a candle to the EV Sentry III's which were the 2nd pair of speakers I acquired (used). I now own 2 pair of Sentry III's (The second pair I acquired from a church in Tulsa, OK - $450.00 for the pair.) The EV Sentry III's crossover is quite simple - like their owner - There is a 3 position knob. Your choice is "A" or "B" or "C". Now "a" or "b" or "c" are concepts I can understand. I know it "attenuates", but HOW it makes the attenuation? Its "magic"!
Chapter 2:
In 1958 when I was 10, I met my first pair of VOTT's...I think they were A4's or something configured similarly. They were enormous...the size of a small house and were powered by a 35 watt Fischer tube amplifier located in the projection booth...and the sound???...WOW....I saw the movie "Oklahoma" at the Fox theater and it may have been my first introduction to "stereo". I was "hooked" on VOTT's from that point on. Like the EV's from Tulsa, I acquired these A6A's from Audiogon. I did not pay much for these A6A's, they were a "bargain" since the theater was going THX. They came from the Lindberg Theater in St. Louis, MO. I try to "rescue" good equipment BEFORE it is "parted out" on E-Bay.
Chapter 3:
At age 55, I am trying to learn a whole new language...the "jargon" of audio that deals with Xmax, Qs and all that.
To Dwight ST - when I read "L-pad"...I thought of the words in the "literal" sense. Now... I believe it is an "attenuator knob". One which keeps the resistance constant, but can reduce or increase the loudness of a speaker.
To ckp: What is a "PM"? Is it a "Power Meter"? I am sure I have something turned wrong. What I sincerely do not understand is the "complexity" of this system's crossover. You are right. Some diagram would be of enormous value. As you know...If you push the white button in, you are "L-padding" something called "MF" only. When you release the white button, you are "L-padding" BOTH "MF & HF" according to the diagram. You have to agree... it presents far more possibilities and difficulties than "A","B", or "C". UNLESS YOU KNOW HOW IT WORKS, which I do not understand. I took apart the crossovers this afternoon and according to the diagram on the top of the box, the crossover point is set at 500hz. I will follow your lead... however, I am unsure of what I am doing by pushing the button in and attenuating the "MF" part only. I spent the afternoon making many adjustments and might have just accidently stumbled upon what ever sounds right. I played Vivaldi's "Gloria" and it was awesome!! The "massive" , high SPL producing subwoofers were the suggestion of one of the "pro's" on the High Effieiency Asylum forum. All they are there for is to bring out (augment) the fullness of much of the organ music I listen to. The logic being - since these are "theater" speakers capable of high SPL's - I should "match" the ability of the subwoofers to the speakers ability. The sales force at Parts Express agreed.
To Dave Fitts: I promise to look up every single symbol and "letter" you provided in your formula. I still have this "language barrier". I am trying to master the hieroglyphics to better determine the meaning.
To Cal Weldon: Thank you for your clear and concise description of an "active" crossover network and how to go about connecting it to the amplifier. I understand every word. No..it is not too simplistic... You've written quite eloquently. You understand that I am struggling with the "basics"...clearly you "understand" your audience. Thank you for your patience.

Thank you all for your patience and understanding AND your willingness to help out. This is a much "friendlier" forum than the "other" asylum.

Sincerely,
Manta-Ray

[Fitts]

Hi Manta Ray, Let me help with decipering the math formulas. In my distant past I was a math teacher and would be glad for the opportunity to explain any part that you have trouble with.

Regards,

[Cal Weldon]

Hi Manta-Ray,

Thank you for your compliments, I'm glad I didn't simplify too much.

I was speaking of the equalizer, not the active crossover, when it came to the hooking up part. If you're really not familiar with an equalizer then email me and I'll give you the laymans basics on it so we don't pester these Altec minds on simple EQ stuff.

Cal

[email protected]

Cheers

[Cal Weldon]

Hi Ray,

I tried to answer your email but they were both returned. Can you add me to your list and let me know when you have, so you can see my response?

Thanks
Cal

[ckp]

Ray,
PM is Private Message. You sent me a Private Message and I tried to reply. I got a message saying you are not accepting private messages.
Hey, mine came from the Linbergh Theatre also. How about that for a small world. I got most of my really old stuff from Village Square theatre. You should have seen what I had to go through to them out. No lights, water up to the front of the stage 3 feet deep and moving 210 cabinets!
I'll draw something and send it to you if you give me your email address. Do you live in the St. Louis area?
Don't feel bad, all this audio lingo is greek to me also.

Ches

[armandh]

it is both simple and complex.
inductors pass less and less as the frequency rises, caps [good ones] pass nothing at DC and pass more and more as the frequency rises. the ideal crossover/speaker setup matches the input and speaker efficiencies as well while maintaining a constant load [impedance / unity power factor]

you are in the right age group
do you remember a Mr Potter as the local Altec rep
Mr Potter had an altec 820-A in the corner of the dining room, driven by an Altec preamp/power amp pair. cir 1963