link to product page of this driver: BLAUPUNKT: Subwoofers
There's a place that sells these for under $30. I'm thinking of buying 8 of these for an infinite baffle build. To me it seems like this would be the best sound-for-the-buck build you've ever seen. Please disprove me because I can not hold off from buying these now.
Are the specs on this sub good? Are the specs good for an infinite baffle build?
There's a place that sells these for under $30. I'm thinking of buying 8 of these for an infinite baffle build. To me it seems like this would be the best sound-for-the-buck build you've ever seen. Please disprove me because I can not hold off from buying these now.
Are the specs on this sub good? Are the specs good for an infinite baffle build?
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Qts .5. Fs 32hz
Can't find xmax.
Natural rolloff at 64hz infinite baffle. (Fs/qts).
But for the price, then maybe upgrade down the road.
Can't find xmax.
Natural rolloff at 64hz infinite baffle. (Fs/qts).
But for the price, then maybe upgrade down the road.
At that price i would buy one and measure its t/s parameters, then strip it down and take a look at the motor.
Xmax (at leadt as defined by voice coil overhang) will be obvious once you have pulled the cone out.
If you cut the spider and surround at about half their width you will also have the ability to check the moving mass.
If it measures ok for the 30 bucks, and has a useable xmax then buy 8 more and hide the dead body in the bottom of the trash can. 😉
Xmax (at leadt as defined by voice coil overhang) will be obvious once you have pulled the cone out.
If you cut the spider and surround at about half their width you will also have the ability to check the moving mass.
If it measures ok for the 30 bucks, and has a useable xmax then buy 8 more and hide the dead body in the bottom of the trash can. 😉
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blaupunkt is not the german brand anymore. only the brand name is licensed to anyone that likes to put a blue dot on their products.
Most of the parameters are available in the manual. Only xmax is missing.
Given that this is a car sub, I’d hazard that xmax isn’t too shabby...
Johan-Kr
Given that this is a car sub, I’d hazard that xmax isn’t too shabby...
An externally hosted image should be here but it was not working when we last tested it.
Johan-Kr
Hi,
😡 Before any conclusions can be made when eyeballing this Driver: Do a consistency check:
xmax is around 12.5 mm, Sd is ~509 cm^2(506 if calculated) but the parameters are all inconclusive and doesnt match like fs= 32 Hz ,no way: but could be 42-43 Hz . Further is that Exm is missing, probably by purpose to misslead.
b🙂
😡 Before any conclusions can be made when eyeballing this Driver: Do a consistency check:
xmax is around 12.5 mm, Sd is ~509 cm^2(506 if calculated) but the parameters are all inconclusive and doesnt match like fs= 32 Hz ,no way: but could be 42-43 Hz . Further is that Exm is missing, probably by purpose to misslead.
b🙂
I'd buy one to test, but not strip it down.
It should be possible to determine effective Xmax by measurement, e.g. the "white dot" method, or determining the input voltage needed to achieve 10% distortion. The rest of the other parameters can be obtained by t/s parameter measurement processes.
Nothing in the above gives any indication of Xmax other than assumption - unless I have gone blind. (Which I seem to do on a regular basis 🙂
This is super critical for infinite baffle, and indeed any serious sub work.
Does someone have this information?
This is super critical for infinite baffle, and indeed any serious sub work.
Does someone have this information?
the fact that the airchamber under the spider is ventilated makes that there is no air forced along the voicecoil, minimizing aircoooling.
it is difficult to estimate the magnet airgap width. the airgap length seems large to allow for production tolerances and cone torque/twist. the winding height could be estimated from this video being the scorched tainted paper voicecoilformer.
it is difficult to estimate the magnet airgap width. the airgap length seems large to allow for production tolerances and cone torque/twist. the winding height could be estimated from this video being the scorched tainted paper voicecoilformer.
Hi googlyone,All
I wrote:
Before any conclusions can be made when eyeballing this Driver: Do a consistency check:
xmax is around 12.5 mm, Sd is ~509 cm^2(506 if calculated) but the parameters are all inconclusive and doesnt match like fs= 32 Hz ,no way: but could be 42-43 Hz . Further is that Exm is missing, probably by purpose to misslead./b
Isn't this Information you could base a Design? You hang up your Serious? consideration/assumption that an IB only could work properly if a single Parameter like xmax is the crucial Parameter when the most important indication is that of the given Parameters are corrupted.
I never assume, I do educated guesses like I've Posted: So why didn't you check my findings?
I gave you an indication of your ‘’Xmax’,fs and Sd’ and that is much more than ‘Nothing ‘
Here is what I based my guesses on, for the given Driver:*
b🙂
*
Blaupunkt_GBW120_SD_Xmax.JPG
Blaupunkt_GBW120_scrutinized_A.JPG
Blaupunkt_GBW120_scrutinized_B.JPG
Attachments
I measured the Fs of the GBW120. Fs= 39Hz +or- 0.5Hz. Sorry to muddy the waters of these specs further. My credentials are: I am a compete noob at audio. This is my first build.
Measured the Fs using a 10ohm resistor in series with driver in free air (no baffle if that matters). Used a o-scope to measure the voltage drop across the resistor while feeding a sine wave sweep through the system. Narrowed it down, then did progressively smaller and slower sweeps. Lowest voltage=Fs. Did I get it right?
Only used the o-scope because my multimeter's precision is poor at low ac voltages.
Side note: these drivers live up to their price point. The basket to cone is glued off axis a few degrees. The center cover thingy does not come close to lining up with the mounting holes.
Thanks to Bjorno whose educated guesses have helped a lot. The box I built before receiving the driver will still work ok despite Blaupunkt's BS
Measured the Fs using a 10ohm resistor in series with driver in free air (no baffle if that matters). Used a o-scope to measure the voltage drop across the resistor while feeding a sine wave sweep through the system. Narrowed it down, then did progressively smaller and slower sweeps. Lowest voltage=Fs. Did I get it right?
Only used the o-scope because my multimeter's precision is poor at low ac voltages.
Side note: these drivers live up to their price point. The basket to cone is glued off axis a few degrees. The center cover thingy does not come close to lining up with the mounting holes.
Thanks to Bjorno whose educated guesses have helped a lot. The box I built before receiving the driver will still work ok despite Blaupunkt's BS
Thank you everyone so much for the replies and the info. I read everything but I also ended up buying 8 of them and building a speaker. It doesn't have the deep end response I wanted. I have a lot to learn about speakers. I'll post a picture of the build here tonight.
There is a measurement process error in that article, which likely explains why the measured low end response seems to be higher than what Hornresp predicts, rather than vice-versa. Do you see it? 🙂
Nope.
Close-miking a 6th Order Parallel BP system that way should work out well - if the vents are the same CSA. That's not the case here.
Close-miking a 6th Order Parallel BP system that way should work out well - if the vents are the same CSA. That's not the case here.