Passive radiator from China?

3rutu5

Member
2018-07-18 11:57 am
Lack of rear pictures makes me suspicious that it's not much more than a shaped rubber diaphragm. Bit of bicycle inner tube might do the same job?

I know that the 10 inch passive radiators I have are the same as the matching subs but just no magnet.
Sub and Systemdek 007.JPG

IMG_0894.JPG
 

3rutu5

Member
2018-07-18 11:57 am
Lack of rear pictures makes me suspicious that it's not much more than a shaped rubber diaphragm. Bit of bicycle inner tube might do the same job?

I know that the 10 inch passive radiators I have are the same as the matching subs but just no magnet.
View attachment 811665

View attachment 811666

I'm 95% certain that are more membrane and no metal frame. I have a peerless one and it is basically a magnetless driver like you mention
 

Nenola

Member
2008-02-25 5:35 pm
As stated before, they are made of rubber surround and a metal plate. I might have couple of that kind but never used them. I did a bt-speaker with nd65, used the round ones, 45mm in diameter to be exact. They act like you might guess, move with the active driver. With these, it's really guessing and good luck since there is no t/s parameters.

I have also tried 2 of these with ND91:

4 Inch Bass Radiator Speaker Vibration Diaphragm Passive Loudspeaker Woofer DIY | eBay
 

3rutu5

Member
2018-07-18 11:57 am
For the price of 6 AUD I got a pair, thought why not, as the YouTube community seem to use them, but I would say if you get them for free or course you would say it sounds amazing...so like mentioned before it's going to be a role of the dice without ts parameters

How did they sound with the ND91's?
 

Nenola

Member
2008-02-25 5:35 pm
Well, to be precise, they don't make a sound :D

But those 4" PR's matched quite nicely with the ND91 in a 2,5 liter enclosure. I don't have any good and valid measurements except this one, taken nearfield and the speaker on a table
 

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Nenola

Member
2008-02-25 5:35 pm

Nenola

Member
2008-02-25 5:35 pm
I would also go for the Tectonic, price is one thing, and because you have T/S parameters, you can actually calculate a suitable enclosure.

I can't remember about the test I made with the Bose clone. It was ok for it's size, but the performance in the enclosure I had (about 0,7 liter), didn't meet my expectations. I switched it for a ND65.

I'm starting a small desktop build (1,5 liters) and I was considering the bigger Tectonic driver. But then I found SB Acoustics SB65WBAC25-4 and found good reviews about it, so I ordered a pair. It should also have quite nice top end, that matters to me more in this build.
 

3rutu5

Member
2018-07-18 11:57 am
I've actually made 3 builds using the tectonic TEBM65 which I really like, but they are 3.5's. I've just finished (almost) my ND65 build, but been fluffing around with spray paint :)

I'll wait until my stuff arrives from banggood before buying the 2inch tebms
 

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3rutu5

Member
2018-07-18 11:57 am
Hey Nenola have you seen these ones? apparently a f3 of mid 80's

Visaton BF37 1.5" Full-Range Speaker 4 ohm

TEBM35 is in blue and the Viston BF37 is in green.

TEMB is showing FS 90Hz in enclosure 0.019cuft (f3 75hz, f6 70hz f10 66hz)

BF37 is showing FS 90Hz in enclosure 0.009cuft (f3 77hz, f6 73hz f10 68hz)

similar results but half the enclosure size.
 

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3rutu5

Member
2018-07-18 11:57 am
Nice specs for so small driver. But check the SPL graph also, that driver handles only 5 watts RMS and is really insensitive (74dB), so there may not be much output.

I also found the xmax for it, it should be +/- 3,4mm

I ended up getting a few pairs of the Visaton BF37's and been pretty happy with the end result. Yes they wont work in a concert and they dont go as loud as bigger speakers, but hey 1x BF37 and a cheap chinese PR per enclosure seemed to work pretty good.

3rutu5 - QUARAN-TEEEEENIE -

Techtalk Speaker Building, Audio, Video Discussion Forum


i'm also experimenting with another version and being a bit creative

Something very small and wacky -

Techtalk Speaker Building, Audio, Video Discussion Forum


anyway even though i couldnt model them the pairing seemed (at least to my ears) works ok, havnt seen the huge movement like the youtubers, but hey i'm also not standing directly ontop of the speaker, i did my trials standing at least 1-2m away.

for the beer can i'm printing another variant which only has 1 PR per driver and also looking at a small BT/AMP board with AT-X that runs off low power, could be a bust as it is a no name chinese board, but once again got my faith in youtube telling the truth :)