I have an old school Blaupunkt subwoofer from when they were a part of Bosch and made good quality stuff. They have since gone bankrupt and someone is piting that name on china junk. It's like new since it's been sitting in my closet. The problem is, WinISD is giving the SPL as 116db, when it is 93db. I tried unchecking the calculate box and putting in 93 db, but it still models the speaker at 112db 1w/1meeter with a 0db transfer function. Is this why I'm getting such a high cone excursion? When I add a 12 db static filter the over excursion problem goes away, but I'm not sure that means cone excursion won't be an issue. I also wonder if the issue may be caused by a misprinted parameter in the manual.manual. But since they are out of business there is no tech support. Thanks for any help with this issue.
Here are the drive's specs. Any look seriously off?
POWER HANDLING 180 Watts rms
540 Watts peak
SENSITIVITY 92 dB (2.83V/1m)
89 dB (1W/1m)
FREQ. RESPONSE 20 - 2kHz
NOMINAL IMPEDANCE 4 ohms
MAGNET WEIGHT 40 oz
MOUNTING CUTOUT DIMENSIONS 9.2 inches (234mm)
MOUNTING DEPTH 5.0 inches (127mm)
AIR VOLUME DISPLACEMENT 0.17 cu.ft.
VOICE COIL DIAMETER 2.0 inches
THIELE-SMALL PARAMETERS
Resonance frequency 30 Hz
Total Q factor (Qts) 0.35
Electrical Q factor (Qes) 0.36
Mechanical Q factor (Qms) 7.02
Volume equivalent compliance (Vas) 2.75 cu.ft.
Linear excursion (Xmax) 0.20 in. (1 direction)
DC resistance (Re) 3.56 (ohms)
Force factor (BL) 10.2 (Tm)
Effective cone area (Sd) 320 (sq.cm.)
Compliance (Cms) 540 (uM/N)
Moving mass (Mms) 61 g
Here are the drive's specs. Any look seriously off?
POWER HANDLING 180 Watts rms
540 Watts peak
SENSITIVITY 92 dB (2.83V/1m)
89 dB (1W/1m)
FREQ. RESPONSE 20 - 2kHz
NOMINAL IMPEDANCE 4 ohms
MAGNET WEIGHT 40 oz
MOUNTING CUTOUT DIMENSIONS 9.2 inches (234mm)
MOUNTING DEPTH 5.0 inches (127mm)
AIR VOLUME DISPLACEMENT 0.17 cu.ft.
VOICE COIL DIAMETER 2.0 inches
THIELE-SMALL PARAMETERS
Resonance frequency 30 Hz
Total Q factor (Qts) 0.35
Electrical Q factor (Qes) 0.36
Mechanical Q factor (Qms) 7.02
Volume equivalent compliance (Vas) 2.75 cu.ft.
Linear excursion (Xmax) 0.20 in. (1 direction)
DC resistance (Re) 3.56 (ohms)
Force factor (BL) 10.2 (Tm)
Effective cone area (Sd) 320 (sq.cm.)
Compliance (Cms) 540 (uM/N)
Moving mass (Mms) 61 g
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The specs you list show sensitivity of 89dB for one watt (2volts in to a nominal four ohms)
or 92dB for 2 watts (2.83volts in to four ohms).
Sounds like 180 (WattsRMS) or 540(WattsPeak) may be entered into the "System input power" input.
This screen shows 125W entered, ~+21 dB over 1 watt.
Looking at the parameters you provided, some values seem a bit off:
- Vas (2.75 cu.ft.): This is a very high equivalent compliance for an 8" subwoofer. A typical value would be around 1 cu.ft. A typo here could be significantly impacting the modeling.
- Qms (7.02): This is a high mechanical Q factor, indicating a very stiff suspension. This could be contributing to the high cone excursion predictions in WinISD.
What is the subwoofer model
and what is the data sheet ( link?)
Sounds like a error in entering the parameters.
Or empirical values on data sheet confused with metric or vice versa
High excursion below the reflex/tuning frequency
is pretty normal.
And many tune high for more port output
then expect it to unload that much faster.
I just use amplifiers with high pass protection
over excursion filters etc etc
Winisd can sum check to 3 decimal points
So I often cross calculate for more accuracy
and then check calculated numbers against datasheet
to see if they are liars or just rounding up numbers
which is somewhat typical.
--------------------------------------------------------
Only entering electrical and mechanical Q ( Qes , Qms )
The calculated total driver Q ( Qts) = .342
Which is close match to data sheet .35
they magically rounded it up.
Huge surprise ,... not really
Be more interesting to see if the fudged BL
So entering MMS , Re and Sd only
cross calculation for BL is 10.27
which is close to datasheet 10.2
So as far as small signal and electrical mechanical data.
Datasheet has no major errors.
No inductance listed so transfer function
wont show high end roll off.
I dont enter Fs I cross calculate it to see if manufacture
is lying or not. With shown magnet force and Sd
Fs is 27 Hz not 30 Hz
So likely rounded up the mass or magnet force
to make it seem slightly more special.
Good enough for a basic alignment.
looking at the Vas
I would expect a real alignment to be the same old
40 to 45 liters basically or 1.5 ish cubic feet
typical volume for a 10" sub like this.
And just tune at Fs or slightly above no more than 3 hz
around 30 to 33 Hz
and what is the data sheet ( link?)
Sounds like a error in entering the parameters.
Or empirical values on data sheet confused with metric or vice versa
High excursion below the reflex/tuning frequency
is pretty normal.
And many tune high for more port output
then expect it to unload that much faster.
I just use amplifiers with high pass protection
over excursion filters etc etc
Winisd can sum check to 3 decimal points
So I often cross calculate for more accuracy
and then check calculated numbers against datasheet
to see if they are liars or just rounding up numbers
which is somewhat typical.
--------------------------------------------------------
Only entering electrical and mechanical Q ( Qes , Qms )
The calculated total driver Q ( Qts) = .342
Which is close match to data sheet .35
they magically rounded it up.
Huge surprise ,... not really
Be more interesting to see if the fudged BL
So entering MMS , Re and Sd only
cross calculation for BL is 10.27
which is close to datasheet 10.2
So as far as small signal and electrical mechanical data.
Datasheet has no major errors.
No inductance listed so transfer function
wont show high end roll off.
I dont enter Fs I cross calculate it to see if manufacture
is lying or not. With shown magnet force and Sd
Fs is 27 Hz not 30 Hz
So likely rounded up the mass or magnet force
to make it seem slightly more special.
Good enough for a basic alignment.
looking at the Vas
I would expect a real alignment to be the same old
40 to 45 liters basically or 1.5 ish cubic feet
typical volume for a 10" sub like this.
And just tune at Fs or slightly above no more than 3 hz
around 30 to 33 Hz
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No, HR calcs ~88.1313 dB/4 ohms/w/m mid band sens. Vs published 89 dB/w/m
Ditto Cms 5.33 Vs 5.4, 9.92 Vs 10.2 Bl and guesstimate HR's 49.5g Mmd Vs 61g Mms (air mass load added)
It's a 10" sub. A 10" circle has 1.56 times the area of an 8" circle.
so 1.75 would seem reasonable. And that would be a reasonable typo.Blaupunkt was a very repeatable company, I doubt they would put outlandish numbers on their speakers. Especially since the conflict on sensitivity would be obvious.
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HUh??Why?
6 liters?
This is a woofer not a bookshelf speaker.
The ports might be 6 liters.....
Qts is around .3
Vas 77 liters
Should instantly tell you about what your looking at.
Running numbers looks like my wild guessing
was close .577 Qtc = 46 liters .707 = 25 liters
Normal everyday butterworth will be just that
46 liters tune 3 Hz above or below Fs to get the alignment.
Here is closed Qtc
.5 = 46 liters
.7= 25 liters
No other magic nonsense to it.
Your either 3 to 6 Hz above or below Fs.
Im happy if butterworth ends up being below Fs
and will ditch the woofer if it has to go more than 3 Hz above it.
To get a alignment.
And there you go, 1 or 2 Hz above Fs
A normal everyday butterworth in 46 liters
all done
6 liters?
This is a woofer not a bookshelf speaker.
The ports might be 6 liters.....
Qts is around .3
Vas 77 liters
Should instantly tell you about what your looking at.
Running numbers looks like my wild guessing
was close .577 Qtc = 46 liters .707 = 25 liters
Normal everyday butterworth will be just that
46 liters tune 3 Hz above or below Fs to get the alignment.
Here is closed Qtc
.5 = 46 liters
.7= 25 liters
No other magic nonsense to it.
Your either 3 to 6 Hz above or below Fs.
Im happy if butterworth ends up being below Fs
and will ditch the woofer if it has to go more than 3 Hz above it.
To get a alignment.
And there you go, 1 or 2 Hz above Fs
A normal everyday butterworth in 46 liters
all done
yeah pretty much nothing surprised me
If its 92 dB
then Id expect vas to be high.
Hits 92 dB and Fs is around 30 Hz
not to bad should be fun speaker
Le not needed for alignment
2" coil with 5mm linear travel.
Id expect the same old 1.1 to 1.7 mH
Just gives you a slight idea if it has much bandwidth
above 150 Hz if wanting to use as a woofer
with say 300 Hz crossover
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Right, the box only loads the driver to its upper mass corner (Fhm) where T/S theory peters out.
Fhm = 2*Fs/Qts'
https://web.archive.org/web/20220707003028/http://www.mh-audio.nl/Calculators/newqts.html
Blaupunkt is recommending enclosure sizes that pushes the driver past the 5mm Xmax at the stated 180 watts rms.