Cardboard Speakers!

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#21
Well, this is the perfect group project.
Kind of the DIY reference speaker project- but so cheap that
everyone can participate!

The link shows lot of good xperimentation to this point- I wouldn'be a bit surprised if we could come up with something pretty darned good in the end.....
 
#23
MEXXX said:
Well, no luck finiding the Sonic Impact T-Amp or the combo pack at my local Target.

There are two more stores within a 20 mile radius that I will check out this weekend.

I'm keeping my fingers crossed and hopes low.



MEXXX
Click to expand...

The stores I found these at had them on the end caps in the vicinity of the stereos/mp3 players/computers. They were with a bunch of other clearance stuff and had no sign or anything on the shelves.

I'm in the far west suburbs of Chicago if that helps any.

BTW, I started to mod one of the amps today. I'm planning on putting it in an aluminum case with dual inputs selectable with a front panel switch and actual binding posts for speaker connections.

So far so good but I'm having a little troube de-soldering the LED. I don't want to overheat the surface mount devices so I'm being careful but it might be time to pull out the desoldering iron instead of using the copper braid.

Once that LED is off the board the rest should be a piece of cake (famous last words).
 
#24
Hi;

Does anyone know if the small amp that comes with the flat speakers is the same type of chip as the class-T 15w amp? I picked one up yesterday and the documentation didn't say much about the amp except to state that it was 2 watts. I checked Sonic Impact's website, but it didn't say either. It sounded good through my fe127Es though.

thanks
 
#26
marcusf said:
Hi;

Does anyone know if the small amp that comes with the flat speakers is the same type of chip as the class-T 15w amp? I picked one up yesterday and the documentation didn't say much about the amp except to state that it was 2 watts. I checked Sonic Impact's website, but it didn't say either. It sounded good through my fe127Es though.

thanks
Click to expand...

I don't know which class-T 15w amp you are referring to but the Sonic Impact that came with the cardboard speakers I bought is a 15wpc digital amp.
 
#29
johnnyx said:
I think those cardboard speakers used NXT technology
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Yes, these are NXT distributed mode speakers. The cardboard is set to resonate by the exciter glued to the backside. Whereas we usually try to not have resonances in a speaker an NXT panel is designed to have as many resonances as possible, close enuff together that they have flattish response. (much much more info at NXT's website).

An externally hosted image should be here but it was not working when we last tested it.


There is a page on these cardboard jobbies.

http://www.nxtsound.com/industries/ind_caseStudies.php?f_id=16

A lot of research has gone into figuring out what shape, resonant qualities, and exciter position give reasonable sound quality. I doubt they will ever achieve real hifi, but they do some things like no other speakers can, and as your example shows, the box your cereal comes in could be a speaker (ie prize is the box not in the box 🙂)

dave
 
#30
Sherman said:
I did attempt to measure FR of the cardboard speakers this morning but couldn't. When playing a 1K Hz tone and setting the volume to 0 db on my meter I encountered a problem. At about minus 2 dB the speakers began emitting a second, completely different tone simultaneous with the 1K Hz signal.
Click to expand...

That is a side effect of how they work... thet resonate.

dave
 
#32
MEXXX said:
To elaborate a little more on the specs its 6 w/rms per channel into 8 ohms @ 0.1% THD+N and 15 w/rms per channel into 4 ohms @ 10% THD+N.
Click to expand...


planet10 said:


That is a side effect of how they work... thet resonate.

dave
Click to expand...


Yeah, at first I thought it was because the "top panel" wasn't attached solidly so I used some removeable masking tape to hold it in place. Same result.

The odd thing (or maybe it isn't so odd) is that the resonance isn't apparent when listening to them with music at high volume.

I guess that with music there are a lot of frequencies at once so the resonance "evens out"? In any case it appears the only way I can get a fr chart made is to drop the SPL meter a lower dB range which means less accurate measurements

BTW, cool looking cardboard speakers in your other post! Gives me ideas!
 
#33
Well its official, none of the 3 Target stores in my area carry the T-Amp, the combo pack, or the stick on transducers.

I guess I'm stuck paying the $20.14 plus $10 s/h each from AmrMart .

IMHO they are still worth that price, but it would have been nice to find them at or even close to the price you found them for Sherman.

By the time I'm done buying all the connectors from PE to make a custom enclosure I will have well surpassed the price of both the amps.
 
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