Theoretical speaker question

[miklorsmith]

Spoken like a guy with a lot of *ahem* inches!  

I have 8 - 10"s for subs.  I guess you could say I'm well endowed.  Being such I have to agree that lots of displacement makes for low, undistorted, controlled bass.

[bobrex]

Legacy moved the factory??  last I knew they were at least building the cabinets here in Allentown (Macungie, actually) at the Allen Organ plant.  Has that changed?

[richidoo]

As any lady audiophile worth her salt will tell you, it's the diameter that matters:

ZuDefPro = 8 drivers * pi * 10*10 = 2514 sq in. = 17.5 sq ft. (Humongous!)   =D>
LegFocus = 6 drivers * pi * 12 * 12 = 2714 sq in = 18.8 sq ft. (Colossal!)  

Speaking of big bass, I heard MMW last week at a medium sized club here in Raleigh renowned for its great sound reinforcement system. Two huge speaker cabinets up front were shaking the wall I was leaning against with each kick drum. We were at least 80 feet away. Bass range was crystal clear and musical but thunderous. It must be 100k cu ft in that room, and it was fully "pressurized," as the home theater guys say..  I can't imagine the drivers/amp that can do that! It didn't hurt our ears like the higher pitched notes did, but it was distinctly physical. Bass and kick downbeats were so loud, they distorted the air so melody instruments sounded "rippled" for a moment. Like in the ocean, little waves riding on bigger waves. It was pretty cool even though I looked like a dork, the old guy with fingers in his ears.....  

My wife was with me at the show and crushed me in the way only a wife can when she said, "Too bad our speakers can't do that." I protested something about needing bigger amps, but the damage was already done...    

[miklorsmith]

Hey, are those woofs on a separate circuit?  I'm using a Crown K2 and it is one mean mutha on the woofers.  No fan, slim fitting for the rack.  It's a cheap, perfect 500 watt stereo sub amp.

Nice package!  woof woof, bow wow wow.  

[Double Ugly]

Hey, are those woofs on a separate circuit?  I'm using a Crown K2 and it is one mean mutha on the woofers.  No fan, slim fitting for the rack.  It's a cheap, perfect 500 watt stereo sub amp.

Nice package!  woof woof, bow wow wow.  

Never tried it, but I've heard nothing but good things about the Crown/woofer mating.  Definitely a relatively inexpensive way of powering your way to excellent bass, assuming the woofers support the possibility.

[richidoo]

Legacy moved the factory??  last I knew they were at least building the cabinets here in Allentown (Macungie, actually) at the Allen Organ plant.  Has that changed?

They moved last year to Springfield IL. No more Allen Organ. According to my Legacy dealer the woodwork guy is not making the cabinets anymore, started his own line of HT racks. They finally updated their website too after 3 years (at least). They showed the new models at CES, wish I coulda woulda shoulda gone...

Hey, are those woofs on a separate circuit?

No, all powered by my 70wpc tubes through the crossover. I have tried Nuforce on the woofers, it was tighter, but they would shutdown on "certain" tracks when pushed "really" hard.   I am building a set of ESP P101s for the woofers. They should be finished in 2010 Maybe?

I thought the DefPro had its own built in amplifiers (active)? I bet that Crown really stomps.

[opnly bafld]

Legacy moved the factory??  last I knew they were at least building the cabinets here in Allentown (Macungie, actually) at the Allen Organ plant.  Has that changed?

They moved last year to Springfield IL. No more Allen Organ.

Bill Dudleston sold half of Legacy to the Allen Organ co. several years ago, he recently bought their share back and has resumed manufacturing in Springfield. \/

On one of my many visits to their showroom (before they moved), I was able to tour the facilities. It was a neat experience.

BTW I own one of their subs the Pacemaker, a dual 15"s in a 6 cu. ft. cabinet, and when I was there making the purchase a gentleman was having them refinish one so he would have a matching pair.
Talk about a lot of inches.

Lin

[bpape]

I never got there when they used to be in Springfield.  Might have to take a road trip one of these days.

Bryan

[miklorsmith]

The Definition 1.5s have a built-in plate amp and 40 hz low-pass filter on the subs.  The mains roll naturally at 40 hz.

The Pros use higher output sub drivers with ragged response that Must be EQd.  Without it, the response curve looks like a roller coaster ride that runs all the way to 1 khz.  They're also passive, so they mandate an EQ box and another amp.  I scoff at simplicity.  

I've noticed a few amp designers are catching on to the high-pass idea for their mains amps.  The Firenze that Srajan reviewed has a variable filter accessible by USB cable to a laptop to design the high-pass filter for the mains feed.  Roger Modjeski can build a 100 hz filter into his amps.  I've thought about commissioning him to do a 70 hz version for me.

Look at what WLM is doing, they're making their systems tunable for the room.  To assume whatever's in the black (or mirror-finish wood) box will be perfect for any particular room is a crapshoot and leads to a lot of dissatisfaction in buyers and a LOT of product on Agon.

[jrebman]

I've noticed a few amp designers are catching on to the high-pass idea for their mains amps.  The Firenze that Srajan reviewed has a variable filter accessible by USB cable to a laptop to design the high-pass filter for the mains feed.

This is similar to what the R-DES does except that it takes your line level inputs, summs them together and then outputs two mono lowpassed, EQ'ed outs to your subs.

  Roger Modjeski can build a 100 hz filter into his amps.  I've thought about commissioning him to do a 70 hz version for me.

I have one of his 2.5 watt EM7 amps which has two sets of inputs -- one full range, and one, as you say, set to 100 Hz highpass.  Changing the frequency is as easy as replacing a pair of capicitors.  I actually plan to do this with mine -- setting it to 70 Hz, that is.  No promises on when, but want to give this a whirl in place of your yammie someday?

-- Jim


quote]

[miklorsmith]

Heck yeah!!

If it works out, maybe a review from Roger in the offing.  He needs more exposure.

[Inscrutable]

As any lady audiophile worth her salt will tell you, it's the diameter that matters:

ZuDefPro = 8 drivers * pi * 10*10 = 2514 sq in. = 17.5 sq ft. (Humongous!)  
LegFocus = 6 drivers * pi * 12 * 12 = 2714 sq in = 18.8 sq ft. (Colossal!)  

Actually, the formula is pi*r^2 or (pi*D^2)/4 ... so you've overstated by a factor of 4. (Think about it ... how do you get the Focus with 6 - 12" drivers to have more than 6 sq ft?)

Hope that lady worth her salt is also very bad at math  

You can also make up for the meat with the motion (think excursion) ... it's the volume of air you move, and thus the volume equivalent of air (Vas) you want to impress the ladies with.

[Inscrutable]

mca,

Back to speaker-quest.  As Bryan and miklorsmith have pointed out, there are many choices, indicated by your preferences and constraints.  What kind of music, how loud, size of room, placement constraints, associated equipment constraints, etc etc.

Ask a question, get 6 in return  

[richidoo]

Actually, the formula is pi*r^2 or (pi*D^2)/4 ... so you've overstated by a factor of 4. (Think about it ... how do you get the Focus with 6 - 12" drivers to have more than 6 sq ft?)

Hope that lady worth her salt is also very bad at math  

You can also make up for the meat with the motion (think excursion) ... it's the volume of air you move, and thus the volume equivalent of air (Vas) you want to impress the ladies with.

Thanks for that correction Inscrutable. Sorry!    It's been a long time since math class. At least I got the formula right. Do I get 1/2 credit for that? Can I retest?

The idea behind legacy's large driver approach (bass and mids) is to keep excursion low to maximise linearity and reduce distortion that rises with excursion. Large diameter drivers  allow same volume diaplcement at lower excursion. Bass is very easy and realistic at high volume.  Their Whisper model has 4 x 15s each side!

[mca]

Problem solved. Just got a sweet deal on a pair of Piega C8Ltd speakers. There are a few others on this forum who's opinion I trust that own the Ltd's and absolutely love them.

I own a pair of the regular C3's and really enjoy them. I am told the step up in sound quality will be huge.

Thanks everyone for your suggestions  


Now the search for a the perfect amp to drive them...