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B&KMan
05-08-2005, 09:19 PM
Hello again Great members,

I try keep reflexion of internal cable and the correlation of internal voice coil driver gage....

I find

a size (awg) of 2235 cable gage of voice coil 15" .

a size (awg) of 2122 cable gage of voice coil 10" .

a size (awg) of 2420 cable gage of voice coil high.

a size (awg) of 2405 cable gage of voice coil UHF.

Actually gage internal cable of all driver is same but uhf is very small and alu and 2235 is big and copper....

so the cable is other expression of commercial approach ??? volume rebate and put same in all??? or it is just a perfect job???


thanks for all info...


Jean.



===========================

btw for this day of 60 years anniversary of the end of second war, I hope Peace for you and your familly...

Zilch
05-08-2005, 11:09 PM
Independent of the AWG of the voice coil wire, the impedance of the driver at the terminals is known.

Ideally the lead wires would be sized to keep the losses proportionate to each driver.

It doesn't matter....

B&KMan
05-09-2005, 08:23 AM
Ideally the lead wires would be sized to keep the losses proportionate to each driver.



Thanks Zilch,

I know this is not a critical point of view for many members but I have a natural theorical question emphasis...

I'm not shure you comments, losses proportionnte, : the cable is create same impedance equal of drive coil and a final result is double impedance ???...

Why do not put a 28 AWG in Twetter ??? is coil is 28 AWG ???

Why put 12 or 14 AWG if coil of lower driver is 20 AWG ??

Thanks for explain theorical...


Jean.

Zilch
05-09-2005, 11:21 AM
The cable is create same impedance equal of drive coil and a final result is double impedance ???...
No.

1) Determine the average impedance of each driver in its range of operation.

2) Determine the average rms current delivered to each driver from the crossover.

3) Size the wires (also considering length and conductive material) such that the IR drop attenuation of each of them in their particular operating frequency range is minimal and equal for all drivers.

4) The attenuation will only be equal when the program material to each driver is exactly the design average.

5) It is a really, really fruitless endeavor to attempt to balance a system in this manner. Know when a bad wank is at hand.

6) Bottom line: size the wires so that they do not contribute significantly to IR loss attenuation.

7) You can use smaller wire on a 16-Ohm tweeter than on a 4-Ohm woofer, yes.

8) Have you ever looked at the wire sizes used in voice coils? You gonna hook up with THAT? By way of perspective, you COULD, actually, and for the short lengths of wire involved, it wouldn't make one whit of a difference.

9) It is easily seen that standard practice diminishes the contribution of the internal system wiring to insignificance.

10) It's only an issue worthy of consideration if you're dealing with very high current levels and long wire lengths, as in wiring drivers for a stadium sound system, for example.

11) Get your drivers and crossovers right and forget about this other suff. It doesn't MATTER!

B&KMan
05-09-2005, 12:12 PM
No.

1) Determine the average impedance of each driver in its range of operation.
2) Determine the average rms current delivered to each driver from the crossover.
3) Size the wires (also considering length and conductive material) such that the IR drop attenuation of each of them in their particular operating frequency range is minimal and equal for all drivers.
4) The attenuation will only be equal when the program material to each driver is exactly the design average.
5) It is a really, really fruitless endeavor to attempt to balance a system in this manner. Know when a bad wank is at hand.
6) Bottom line: size the wires so that they do not contribute significantly to IR loss attenuation.
7) You can use smaller wire on a 16-Ohm tweeter than on a 4-Ohm woofer, yes.
8) Have you ever looked at the wire sizes used in voice coils? You gonna hook up with THAT?
9) It is easily seen that standard practice diminishes the contribution of the internal system wiring to insignificance.
10) It only matters if you're dealing with very high current levels, as in wiring drivers for a stadium sound system, for example.



Thanks again for reply Mr Zilch

Well, I try to understand why in few JBL speakers the cable is same for loud 15" (who receive 80% watts) and for the UHF where 2% power is present....

In other point of view, why the recent speakers is put 14 AWG in low , What is theorical rule... I suppose never cie serious (JBL) run to " nozemeter" So the watts is rule ??? if I put hight current power 1000W and speaker rated 650 Watts rms (probably run in 1000W peak) so the 20 AWG on 15" is ok ???

Other point of view, why put 14 in tweeter (voice coil is 32 AWG and ) and put 14 in voice coil 15" ( maybe 20 or 24 awg) ??? 14 AWG is standart rated for 15 amp.

so I just try theorical explanation of the select wire for best jobs as possible, too big shunt hight frequency and drop inpedance but up capacitance. Right

It is a equilibrium of this 2 aspects impedance and capacitance ?? in according to watts and frequency ???

At this regards I try to found rule of the power AWG voice coil and the internal cable optimisation...

thanks again for your time and for any other to try to respond on this...

Dougie
05-09-2005, 12:27 PM
Here is a calculator from Parts Express website.

http://www.partsexpress.com/resources/cablecalc.html

Doug

Zilch
05-09-2005, 02:01 PM
Here's scans of 3-foot lengths of:

A) 18 AWG (7 X 26) tinned stranded wire such as was commonly used by JBL for internal wiring (top),

B) 12 AWG Romex solid electrical wire,

C) Cat 5e cable, all 8 conductors stripped, twisted together, and soldered.

For reference, I've also provided D) just the test leads clipped together to illustrate the measurement calibration.

Finally, at E) is Cat 5e with the "whites" vs. the "colors" separately twisted and soldered, all tied together at the distal end.

I think I know what I'd be tryin' on MY tweeters, probably, if I used them. :p

['Course, I'd be wantin' somebody to replicate this before committin' to it unequivocally.]

Spend $160 and "discover" the world of wire:

http://audioheritage.org/vbulletin/showthread.php?t=5662

Zilch
05-09-2005, 11:15 PM
Here, then, are high-resolution sweeps of 2402H UHF driver and the same driver on a 3-foot Cat 5e cable constructed per E), above.

Cable added the predicted 0.04 Ohms (0.5%) to the impedance uniformly throughout the range.

Larger gauge cable of identical construction (and shielded, if desired, for biasing) is available to reduce the impedance contribution further.

Inductance, capacitance, and tribo-electric characteristics remain indeterminate. :p

[Note: 4 X 24G = 18+G]

B&KMan
05-10-2005, 08:28 AM
Here, then, are high-resolution sweeps of 2402H UHF driver and the same driver on a 3-foot Cat 5e cable constructed per E), above.


THE 2 GRAPH IS LOOK SAME WHAT IS THE SECOND ???



Larger gauge cable of identical construction (and shielded, if desired, for biasing) is available to reduce the impedance contribution further.
[Note: 4 X 24G = 18+G]

WHAT IS EXACT NAME LABEL PLEASE ???


========================

p.s. Thanks for hint, of pict... very interesting...

It is shure I'm trying this test soon with my b&K...



Spend $160 and "discover" the world of wire:
http://audioheritage.org/vbulletin/...read.php?t=5662

BTW My name is not a fantasy B&K !! = Bruel & Kjaer :D
(se pict)

B&KMan
05-10-2005, 09:00 AM
First very thanks for time and effort to expose this experience...


I Just analysing your result and mmmmmmmmmmmm....

1---- the phase curve is ideally +-10% of original signal (acording to
instrumental mesure) but it is less than 1 degree for intentisy
acoustical mesure...... On A & C the shift is go 0 to 90%
(annulation...) HEEEK !!!

2----the B phase is weird ripple but relative flat phase!!!! :blink:
but completely shift at 90 degree all the time...
so error in start calibration ???

3 ----Maybe zoom effect but the second serie of pict expose the shift phase is relatively flat and corresponding... But it is not a dual analyser ??? Wy do not put original signal and compare with second signal ???

I'M not shure to understand why perform this instrument mesure because the response is the differencial of a-b signal ( commonly call H1 )

thanks to explain a little bit your interpretation.

Finaly the phase and frequency is a real aspect of analogue signal...
not impedance... no ???

Jean.

Zilch
05-10-2005, 10:31 AM
THE 2 GRAPH IS LOOK SAME WHAT IS THE SECOND ???
First is tweeter without cable. Second is tweeter with cable. The difference is a 0.04-Ohm higher impedance with the cable, reflecting the added impedance of the cable itself.

The point illustrated is that there are no impedance anomalies introduced by using 3 feet of this cable configuration to connect this tweeter.


WHAT IS EXACT NAME LABEL PLEASE ???This is General Cable Category 5e Data Communications Cable, 4 pair 24 gauge, available at Home Depot. I suspect that any generic cable manufactured to Cat 5e specification will behave similarly. Parts express sells Carol brand. Category 6 cable may have improvements in other characteristics, as the twisted pairs are kept separate from one another in that design by a central spline.

The simple innovation I have proposed here is to use one member of each twisted pair as the supply and the other as the return. This is accomplished by connecting the "whites" versus "colors" together at each end for use with the driver.

Others have earlier suggested that twisting the driver connection wires together would serve to improve performance. No doubt there are extensive discussions of such techniques elsewhere on the internet.

I have merely used simple impedance measurements to demonstrate the potential utility of controlled specification datacom cable for this purpose. I leave it to you and others to determine empirically how it performs with respect to other characteristics.

For now, I'll likely be using it to connect high-frequency drivers, if only because I have rolls and rolls of it for premise wiring here. :D