Peerless 850146 "replacement" 830668

[fat_terry]

I am on the point of ordering components for a tri-amped
Peerless 850146/CSX257 (closed box), Peerless P13W-H-00-08 (closed) mid and Vifa D27TG-45-06 tweeter.

Upon ordering from my supplier (in Australia) Im told the 850146 is no longer available and "superceeded" by the 830668.

Well, I couldnt find a whole lot on the web (or here, or LSDG) on that topic. Plugging the numbers in to Unibox I notice the 850146 requires a closed volume of 37L. The 830466 requires 66L. Now that's not what I call a direct replacement ?

On that topic I have two questions if anyone has any experience or opinions :

1) If I use heavy fill for the 830668 I can reduce the box volume to 40L. If, say, I can live with this is the 830668 really a reasonable replacement for the 850146 (which seemed to be respected for its good bass reproduction and 9mm Xmax) in other respects (so in time might I expect to see it in LSDG as a recommended woofer as the 850146 still is). Or should I just say "bad luck" and scrap my design, well the woofer, and start over again looking for a decent woofer for the same price as the 850146.

2) I also notice that according to Unibox the max input power to stay within Xmax is 45W with the 830668, versus 60W for the 850146 (presumably due to the 8mm Xmax versus 9mm respectively). Is that something I should be concerned about for normal living room listening, considering Xmax is only reached at around 60Hz and below for that input power ? I dont have much of a grasp for what that power input over that frequency range means in the real world.

But the differences highlighted by Unibox are big enough for me to ask the questions, even if Im disappointed to say the least to complete my design only to find a major component has become obsolete in the time itsd taken me to do it !

Of course once Ive built the project I will probably be able to answer all these question myself !

Terry.

[ashok]

Hi Terry,
There is a difference between the two drivers. The resonant frequency is higher and Vas is lower in the new one .
The simulation shows a difference but it is not 'too' different. In practice the difference might not be very audible (?).

The Red curve is the 850146 in a 34 liter box with no damping. The blue, green and grey lines are the 830668 . The grey line is in a 45 liter box with damping on all sides. The blue line is in a 34 liter box with no damping and the blue line is in a 34 liter box with damping on all sides.

Additionally the 'linear' travel for the 830668 is 24-8 = 16mm peak to peak . The 850146 is 23-8 = 15 mm peak to peak.
So do not bother about the small differences . Looks like the new drive is a shade better. We do not know how the 9mm was specified on the old driver as it does not say 'linear' or "max" .

The -3db points are different but I think the new driver will most probably sound as good in practice.

I'm just about to switch on my 850146 in a 34 liter sealed box .
The active c/o is not ready yet.

Cheers.

Edit:I've deleted the Plots .
The plots are incorrect for the 830668. I'll rework it and post it a bit later.

[ashok]

Here are the response plots.

Red plot 830668 in a 37 lit box with a Q of 0.764 and with no damping in the box.

Green is 830668 in a 48 liter box with Q of 0.709 and no damping.

Blue is the 850146 in a 37 liter box with a Q of 0.69 and no damping.

I think you can go ahead with the 830668 driver. It should be just as good with some minor changes in the box dimensions or the same 37 lit box filled with damping material.

[ashok]

I measured the Q of the 850149 in my 37 liter box. No absorbent . The box has a small hole for the speaker cable at the moment. So it isn't ideally sealed.
Fb = 50 Hz ( simulated 48 Hz)
Qc = 0.76 ( simulated 0.69 ). This should change a bit when the box is properly sealed .
I can also use an absorbent to reduce Q a bit.

Actual listening might take a while unless I can get my breadboarded active crossover working .

Cheers.

[fat_terry]

Thanks for your replies ashok - and the plots. They do seem similar in the simuation, although I do wonder why they've changed the driver with no huge improvements obvious.

Im still a bit puzzled by the apparent significant difference in max input power to keep within Xmax - although perhaps Im using the wrong figures having entered 9mm for the 850146. If I use your figures should I be putting something like 7.5 into Unibox (although the data was preloaded in Unibox) ? If I did that they'd look similar in max power before Xmax is exceeded.

And if the drivers are that similar in reality I guess my concern about reaching Xmax below 60Hz is not warranted, only because so many people use the 850146 and nobody complains about it hitting Xmax ! Im not sure I get why though, 45W doesnt seem like a lot of power to me .....

Terry

[rabbitz]

Forget about the xmax limitations in the software as playing music is completely different. If the software was correct, my walls should be splattered with driver cones. Use it as a guide and also when comparing drivers.

There was a really good discussion on this recently in the fullrange forum.

BTW, none of the new Peerless drivers are direct replacements and are only a suggested alternative.

[ashok]

Hi Terry , Rabbitz is correct about the drivers being "suggested" replacements.
About the X max. The cones are capable of much more movement than "linear Xmax" which is a bit higher in the new driver.
Linear X max for 850146 is 7.5mm . Max safe X max is probably 9mm .
That works out to be 20% over the 'linear Xmax'.
For the 830668 , "linera Xmax " is 8mm and so 20% higher is 9.6mm .
In Bass Box Pro , they use 50% of linear Xmax to get the physical Xmax !
In the physical Xmax condition the coil will be partly out of the magnetic circuit ! Happens in real use and not noticeable unless it gets to be too much.

At 60Hz the 830668 probably will be slightly better than the 850146 .
The driver was probably changed as they have changed the basic basket design and possibly some changes to the cone / coil assembly. However the rubber surround and spider appear to be similar. Coil length has gone up a bit and so that's a good thing .

I doubt if you will find any significant difference between the drivers . Just go ahead and use it. For X max you can put in 9.6mm or 13.5mm as BassBox does !! Maybe 10mm is a safe bet. I've driven the cone at 10mm using 20Hz signals and I heard no terrible noises. But then this is supposed to be only applicable for short duration signals ( like music ) and not continuous sine waves.
Cheers.

[fat_terry]

Thanks for all the info. I suspected I was dwelling on theory too much, but then until I build, listen and adjust that's all I can do !

I confess to trying to get away with just Unibox for my first initiative, especially given its triamped, for just one speaker project shelling out for some of these packages is prohibitive. But even so, its all about understanding the drivers in the real world too.

So, thanks for the advice, the order has gone in ! Now I cant wait to build it all :-).

T

[fat_terry]

Ok, Im now looking at the box design on more detail having chosen and ordered the drivers. Im using UniBox 4.04. But I get some quite different numbers than ashok does ?

For the 830668 :

For a Qtc of .764, no fill, no leaks, Unibox says 51.6L versus your calcs of 37L.

and Qtc of .709, no fill, no leaks, 69.1L.

something isnt right here. Im assuming its me, but Im lost to what Im doing wrong. Here's what Im using :

Drive Unit Parameters
Peerless 830668
Fs 33.30 Hz
Re 5.60 Ohm
Qms 4.85
Qes 0.57
Sd 335.0 cm2
Vas 69.3 l
Xmax peak 8.00 mm
(Le) 3.30 mH
(Le2) 0.00 mH
(Re2) 0.00 Ohm
Nominal Power 45.7 W

External Components
Rs 0.00 Ohm
(Lco1) 0.00 mH
(Rco1) 0.00 Ohm
(Cco1) 0.00 uF
(Lco2) 0.00 mH
(Rco2) 0.00 Ohm
(Cco2) 0.00 uF

Parameters of Single Unit
SPL at 1 W 1 m 88.4 dB
SPL at 2.83 Vrms 1m 90.0 dB
Max SPL at 45.7 W 105.0 dB
Qts 0.510
Effective Qts 0.510
Mms 51.96 g
Cms 0.440 mm/N
Rms 2.241 kg/s
Bl 10.33 Tm
Ref. efficiency, n0 0.432 %
Efficiency, n 0.432 %
Applied voltage 16.00 Vrms

Drive Unit Nondirectional Range
Piston range 532 Hz

Box Type
Suggested box type Closed
Down fire application 0.97


Which gives :

Vb 53.6 l
Fb 50.44 Hz
F3 50.44 Hz
Qtc 0.707
Response peak 0.00 dB
Max power input 45.7 W

Design by Vb and Q
Physical Vb 69.1 l
Absorption, Qa 120
Leakage, Ql 30
Alpha, a 0.990
Vb 70.0 l
Fb 46.97 Hz
F3 46.56 Hz
Qtc 0.709
Response peak 0.00 dB
Peak at none

[fat_terry]

Drat ! Looks like I can only think for 30 mins. then I cant edit my post ! Here's the revised version, please disregard the last :



Ok, Im now looking at the box design on more detail having chosen and ordered the drivers. Im using UniBox 4.04. But I get some quite different numbers than ashok does ?

For the 830668 :

For a Qtc of .764, no fill, no leaks, Unibox says 51.6L versus your calcs of 37L.

and Qtc of .709, no fill, no leaks, 69.1L versus you 48L ?

Something isnt right here. Im assuming its me, but Im lost to what Im doing wrong. Here's what Im using :

Drive Unit Parameters
Peerless 830668
Fs 33.30 Hz
Re 5.60 Ohm
Qms 4.85
Qes 0.57
Sd 335.0 cm2
Vas 69.3 l
Xmax peak 9.00 mm
(Le) 3.30 mH
(Le2) 0.00 mH
(Re2) 0.00 Ohm
Nominal Power 100.0 W

External Components
Rs 0.00 Ohm
(Lco1) 0.00 mH
(Rco1) 0.00 Ohm
(Cco1) 0.00 uF
(Lco2) 0.00 mH
(Rco2) 0.00 Ohm
(Cco2) 0.00 uF

Parameters of Single Unit
SPL at 1 W 1 m 88.4 dB
SPL at 2.83 Vrms 1m 90.0 dB
Max SPL at 100 W 108.4 dB
Qts 0.510
Effective Qts 0.510
Mms 51.96 g
Cms 0.440 mm/N
Rms 2.241 kg/s
Bl 10.33 Tm
Ref. efficiency, n0 0.432 %
Efficiency, n 0.432 %
Applied voltage 23.66 Vrms

giving :

Closed Box
Standard Design
Vb 53.6 l
Fb 50.44 Hz
F3 50.44 Hz
Qtc 0.707
Response peak 0.00 dB
Max power input 57.8 W
Design by Vb and Q
Physical Vb 69.1 l
Absorption, Qa 120
Leakage, Ql 30
Alpha, a 0.990
Vb 70.0 l
Fb 46.97 Hz
F3 46.56 Hz
Qtc 0.709
Response peak 0.00 dB
Peak at none



Now being somewhat puzzled, Ive put the same parameters into WINISD. That suggests a box of 77L for Qtc .71, presumably no fill no leaks. Its acceptably close to Unibox's 69L (in fact WinISD suggests 69L gives a Qtc of .72), its not remotely close to the figures you quoted ?

WinIsd params as follows :

Driver : Peerless 830668
Vas : 69.3
Qts : 0.51
Fs : 33.30
SPL : 88.70
Number of drivers : 1
Box type : Closed
Box size : 69.1 l



Where have I left the path of sanity !! ?

Terry.