refitting logitech z-2300 sub into different cabinet: room for improvement?

Hi all

I have just taken apart the sub cabinet of my Logitech Z-2300 and I want to build it into my furniture to have the ugly box out of sight. Having it taken apart, I wonder if there is room for improvement.

1. could I replace the driver (it turns out it is a Tang Band W8-670Q). specs (wich mean absolutely nothing to me):
Fs = 42.95 HzRe = 7.80 ohms
Le = 7328.42 uH
L2 = 3120.63 uH
R2 = 52.25 ohms
Qt = 0.52 Qt
Qes = 0.57 Qes
Qms = 6.49 Qms
Mms = 50.81 grams
Rms = 2.112233 kg/s
Cms = 0.000270 m/N
Vas = 10.35 liters
Sd= 165.13 cm^2
Bl = 13.755757 Tm
ETA = 0.14 %
Lp(2.83V/1m) = 83.66 dB


Or could I imrove the size of the cabinet:

The original enclsure is 30,5 cm x 25cm x 25 cm (inside) = 12" x 10" x 10".
Maximum inside size of the new enclosure is 23cm x 41cm x 38cm (= 9.1" x 16,1" x 15")


The original is ported with some weird U-shaped plastic tube, diameter of the outside hole 5,3", the diameter of the tube itself is 3", the length of the tube about 22".


I hope the specialists here have some interesting things to say!


Thanks in advance!


Erik Blokpoel
 

tb46

Member
2006-01-09 7:04 pm
Texas
Hi erik1971,

Here is the Boxplot output for your speaker in a box with your dimensions, vented w/ 3"Dia. Port.

Regards,
 

Attachments

  • Logitech_Boxplot.jpg
    Logitech_Boxplot.jpg
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..I wonder if there is room for improvement.

Fs = 42.95 HzRe = 7.80 ohms
Le = 7328.42 uH
L2 = 3120.63 uH
R2 = 52.25 ohms
Qt = 0.52 Qt
Qes = 0.57 Qes
Qms = 6.49 Qms
Mms = 50.81 grams
Rms = 2.112233 kg/s
Cms = 0.000270 m/N
Vas = 10.35 liters
Sd= 165.13 cm^2
Bl = 13.755757 Tm
ETA = 0.14 %
Lp(2.83V/1m) = 83.66 dB


Or could I imrove the size of the cabinet:

Erik Blokpoel

Hi Eric,

Why not build a multi-folded TH using 0.5" Ply (using the driver specs here-above):

b:)
 

Attachments

  • Logitech-z-2300_37L_f-3dB~29Hz_TH.JPG
    Logitech-z-2300_37L_f-3dB~29Hz_TH.JPG
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Greets!

Probably way more correct than using none at all due to the mid-bass hump it causes, though with no way to know how close either of the specs posted so far may be to reality, it's all just a bunch of hand waving, so I'm inclined to just put it in the OP's desired cab and use the vent from its original cab.

WRT BoxPlot, I'm with you, it and the math routine it's apparently based on has been my default designer for all types of alignments including some horn alignments for several decades now and ticks me off no end that it won't work for long in XP Pro before shutting down.

It's only real drawback for me is its lack of inductance effects on the response and of course it calcs too long a vent for anything but an ideal uniform particle density loading, but then I was 'raised' to do final tuning in-room for best overall performance, so not a big deal, especially now that we have MJK's accurate enough software to sim high aspect ratio alignments.

On a semi-related note, the memtest86 you suggested awhile back confirmed my computer's RAM was up to par, so for awhile after was at a loss as to why mine was so slow with some of HR's plots.

Anyway, long story short, it turned out to be power supply overheating that had apparently been a problem since day one and once repaired, it now zips right along with MathCad, HR, Excel, etc. like never before, so thanks for the nudge that got me past just accepting its (sub par) performance.

GM
 

tb46

Member
2006-01-09 7:04 pm
Texas
Measuring driver parameters.

Hi erikb1971,

Yes, you can measure the Thiel/Small parameter with a simple multimeter, a small resistor and your computer as a signal generator. There are a lot of references on the web.

Here is Brian Steele's website:
The Subwoofer DIY Page - Measurements

and

Elliott Sound Products:
Measuring Loudspeaker Driver Parameters

Having that data will allow you to optimize the enclosure for this particular driver.

Regards,
 
HA!
Bought a multimeter today (sky tronics 600.219)
Turned my iphone into an oscilator
Bought a resistor, took the stereo from the bedroom and voila!

Source Voltage Vs 0,81 Volts Source Resistance Rs 5,50 Ohms Speaker DC resistance Re 6,40 Ohms



Voltage across R
0,37 Volts Source current (DC) Is 0,07 Amps



Voltage across R at resonance Vm 0,13 Volts Current flow at resonance Im 0,02 Amps Resonance frequency Fs 41,00 Hertz



Speaker impedance at resonance (Rm) Rm 28,77 Ohms



-3dB current Ir 0,04 Amps r0 r0 2,88
-3dB voltage Vr 0,22 Volts







Fh
47,10 Hertz Fl
35,80 Hertz Fs check
41,06 Hertz
So, my first ever measuring of a speaker... now what?
 
HA!
Bought a multimeter today (sky tronics 600.219)
Turned my iphone into an oscilator
Bought a resistor, took the stereo from the bedroom and voila!

Source Voltage Vs 0,81 Volts
Source Resistance Rs 5,50 Ohms
Speaker DC resistance Re 6,40 Ohms

Voltage across R 0,37 Volts
Source current (DC) Is 0,07 Amps

Voltage across R at resonance Vm 0,13 Volts
Current flow at resonance Im 0,02 Amps
Resonance frequency Fs 41,00 Hertz

Speaker impedance at resonance (Rm) Rm 28,77 Ohms

-3dB current Ir 0,04 Amps
r0 2,88
-3dB voltage Vr 0,22 Volts

Fh 47,10 Hertz
Fl 35,80 Hertz
Fs check 41,06 Hertz

So, my first ever measuring of a speaker... now what?