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Bass? We don't need no stinking bass! [message #35008] Thu, 07 February 2002 12:59 Go to next message
BillEpstein is currently offline  BillEpstein
Messages: 886
Registered: May 2009
Illuminati (2nd Degree)
I fixed a big hole in my CD collection today, Dark Side of the Moon.
Last had it on vinyl, P.D.
Also took out the "JBL-Lite" m-115 woofers from the 3677's and put in the 2226J's that had been quietly sitting in the corner.A little closer to building the 7Pi's and I wanted to break them in on the HT setup as the Olympics will be on 24/7.
So I get out the Bernz-o-matic, burn the tape off the CD packaging, and fire up the cheap DVD player with the aforementioned CD.
Oops, almost forgot the background and foreshadowing. On the Speaker Asylum there is an ongoing post about how low the Paradox 1 goes in the bass vs other bookshelf speakers.
So the opening cut is making the walls shake with the sub-woofer untouched at a level that had been quite natural with movies, even Pearl Harbor. I decide to hear what the JBL's do on their own and cut off the sub output. Night and day. The bass sound is there but not the sound pressure. I take the disc out to the living room and spin the music rig, Theatre 4 Pi's, ya' know. Same thing. Notes are there but not the air movement.
And these guys think they're hearing bass with 5 1/2, 6" drivers in quart containers?
Now I don't care whether you're at a rock concert or in a symphony hall, the lower octaves of bass instruments are pushing pressure waves against your ears. Even baroque Continuo has a little of that.
It's tactile as well as auditory.
These little speaker guys need to come to Lima next month.
Also have to write, even tho' they've been on only an hour or so, what Wayne say's about the JBL being clearer and cleaner than the Eminence is absolutely true. Lyrics and spoken voice in the mid-range much more articulate. Can't wait to build the 7 Pro's!
[wide grin] [message #35009 is a reply to message #35008] Thu, 07 February 2002 13:42 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18676
Registered: January 2001
Illuminati (33rd Degree)
I'm with you all the way!
Don't tell me that , Till!!! [message #35015 is a reply to message #35008] Thu, 07 February 2002 15:47 Go to previous messageGo to next message
Garland is currently offline  Garland
Messages: 269
Registered: May 2009
Grand Master
I haven't even gotten my Theater 4's wired up yet and your pulling the rug out from under me: "JBL's clearer than Eminence"! Now what do I do; the neurotic music loving audio idiot that I am! Sigh!

G.

Build another pair with JBL and [message #35017 is a reply to message #35015] Thu, 07 February 2002 15:51 Go to previous messageGo to next message
mikebake is currently offline  mikebake
Messages: 243
Registered: May 2009
Grand Master
use the Theatre series for your back-up or "spare room" pair. Then, when it is time to party, fire 'em ALL up.
I'm 5 minutes away from ...... [message #35018 is a reply to message #35009] Thu, 07 February 2002 15:59 Go to previous messageGo to next message
BillEpstein is currently offline  BillEpstein
Messages: 886
Registered: May 2009
Illuminati (2nd Degree)
placing the 3677's upside down on top of the 4 Pi's and wiring them parallel, 12 ohms, right?
How's that for an MTM configuration?

hey MikeBake, Straight 8's coming to Lima? (nt) [message #35019 is a reply to message #35017] Thu, 07 February 2002 16:14 Go to previous messageGo to next message
BillEpstein is currently offline  BillEpstein
Messages: 886
Registered: May 2009
Illuminati (2nd Degree)
nt
Parallel speaker connections [message #35022 is a reply to message #35018] Thu, 07 February 2002 19:34 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18676
Registered: January 2001
Illuminati (33rd Degree)
A loudspeaker is a complex load, having an imaginary (reactive) and a real (resistive) part, so the two curves will combine as a function shown by the parallel impedance equations and with a phase determined by the combined reactive loads.

On the other hand, you don't care about the whole curve, just an average impedance value, yes? Looking at it that way, you have a loudspeaker with 8 ohms advertised impedance and another with 16 ohms advertised impedance, connected in parallel.

So use the forumla Zt = 1 / (1 / Z1 + 1 / Z2), and you'll find that Zt is 5.3 ohms.

In practice you'll find a little different story. This 5.3 ohm impedance will be in the 100 to 500Hz range, where your four π speaker's impedance is closest to 8 ohms and your JBL 3677's impedance is closest to 16 ohms. Below 100Hz, you'll have several impedance peaks - two from each loudspeaker. Above 500Hz, the impedance of the woofers starts to rise, approaching an open circuit where other components are dominant. By the crossover frequency, the tweeter circuits provide most of the load, which is of a slightly higher but relatively linear impedance.

So all that to say no matter how we slice it, a loudspeaker's impedance curve is more like a roller coaster than it is a fixed resistance.

Re: Bass? We don't need no stinking bass! [message #35024 is a reply to message #35008] Thu, 07 February 2002 19:47 Go to previous messageGo to next message
Adam is currently offline  Adam
Messages: 419
Registered: May 2009
Illuminati (1st Degree)
I found it quite disheartening about what you say about the JBL's vs the Eminence. I really wanted the clearest sound possible.... Oh well. I guess I'll build some more speakers with JBL woofers and eminence compression drivers next time.

And you can hear those notes with 6.5" speakers if you do it right. Maybe not loud, but right enclosure, right speaker, it's perfectly plausable.

Adam

Price/Performance [message #35027 is a reply to message #35024] Thu, 07 February 2002 21:20 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18676
Registered: January 2001
Illuminati (33rd Degree)
It's all a matter of performance for the price - a "price/performance ratio." Think about this: I build a lot of Theater Series four π speakers with Eminence Delta 15's in them. They're excellent. I'm running a pair of ten π horns in my home, with JBL 2226 components. But when I fire up the four π's to test 'em, I can't seem to turn them off. They sound so good, I really enjoy listening to them instead!

A complete four π loudspeaker, assembled and ready to play, costs less than the JBL 2242 woofer from a Professional Series four π-18. The cost of a pair of these Theater Series four π speakers plus the ultra-expensive palletizing and trucking them across country is still hundreds of dollars less expensive than a single TAD 4001 compression driver, without its required horn. So really, it's not a "fair fight" to compare a component that costs a hundred or two-hundred dollars to one that costs several hundred or even a few thousand dollars.

I certainly wouldn't feel "disheartened" to own speakers with Eminence components. I'll tell you what would disgust me. To purchase a single 50 watt speaker motor that costs more than $15,000.00 would disgust me. That's what I mean by "price/performance ratio."

Re: Price/Performance [message #35028 is a reply to message #35027] Thu, 07 February 2002 22:01 Go to previous messageGo to previous message
Adam is currently offline  Adam
Messages: 419
Registered: May 2009
Illuminati (1st Degree)
Thanks for the reassurance, Wayne :)

I will give you a pat on the back... I placed my satelites on their sides on top of the two 10 pi enclosures to give them some treble, and the whole system has just completely come alive... The bass is tight, punchy, it sounds deeper, midrange is great... its all just great... I can't wait to get the horns in.

My friend has been helping me (doing most of the tough work) get the bracing finished on the second set... We should be done that up by tomorrow.

I'm very excited!!!

Adam

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