I have a customer that has a set of 5 Bose double cubes (the original size, not the smaller ones), but no Bose sub to use for the internal crossovers. Can I set the receiver's high pass at like 100 or 120hz and be safe, or is there more to it than that? I have talked to Bose "techs" who say that the crossover is some super special thing and if you don't use it you WILL blow the drivers...
(Of course I would prefer that he use the cubes as door stops, but sometimes it isn't that easy....)
What's the TRUE doctrine?
(Of course I would prefer that he use the cubes as door stops, but sometimes it isn't that easy....)
What's the TRUE doctrine?
make computer speakers out of 'em, usng the JBL 12-watt amplifier on ApexJR. Only needs a 12v transformer, it has its volume and tone knobs on the board.
That's not quite the answer I was looking for. Basically I need to know if it is safe to cross them over using the built-in x-over in a receiver, and if so, what frequency?
are you operating the speakers near maximum rated power?
it'd be more informative if you had more info on why the crossove is so super-special.
it'd be more informative if you had more info on why the crossove is so super-special.
i know from experience that if you unplug the cubes, you can hear voices through the bass module. so the cubes are crossed over pretty high. might not be able to just use the cubes.
Yes, I have also noticed the voices out of the bass module, and I wasn't sure if that's because it's crossed over so high, or because the module is only on a 6db/octave slope or something.
They are going to be in the guy's home theater, so I am sure they will be running at pretty high volume levels.
They are going to be in the guy's home theater, so I am sure they will be running at pretty high volume levels.
I know this is short of specifics but I read that the crossover is high but with a very steep slope: 180Hz or 200Hz and 6th order (36dB/oct) seems to ring a bell. The cubes produce very little bass so the XO needs to be high and the sharp slope is to mitigate localisation of the sub.
I wouldn't run the cubes at more than 10W or so if you only had a 80Hz XO on them. Try it - carefully - and see when distortion becomes evident.
Nice one,
David.
I wouldn't run the cubes at more than 10W or so if you only had a 80Hz XO on them. Try it - carefully - and see when distortion becomes evident.
Nice one,
David.
Don't expect any miracles
Yeah, I don't think your friend will have any luck with the cubes. He might as well hang some cone tweeters from some coathangers for that matter.
Yeah, I don't think your friend will have any luck with the cubes. He might as well hang some cone tweeters from some coathangers for that matter.
The XO is somewhere up around 250 Hz. You'll probably blow the cubes with a conventional sub XO. As well, the stock XO probably contains some EQ to get the cubes to play that low so they would sound even worse than normal without it (if that's possible.)
http://www.intellexual.net/bose.html
http://www.intellexual.net/bose.html
An externally hosted image should be here but it was not working when we last tested it.
Now THAT'S the stuff I needed to hear! Yeah, I am not a fan of Bose, at least not anything made in the last decade or so. Looks like I'll have to help this guy let go of the cubes and move on to something better (and probably much cheaper).
Thanks for the insights!
Thanks for the insights!
I had the dubious honour of visiting Bose in 1993 or so. We went into their Bunker where they were testing their cone *tweeters* up to visible excursions of 1-2 mm. Continuously.
I am not a fan of B3$% (I didn't know that this word is on the same blacklist as OP&!P and fe%db"1k 😉 ) either, in fact far from that.
While many of the facts given on the previously mentioned webpage may be true, some of them do not withstand technical scrutiny.
I can agree that plastics usually don't isolate EMC very well, but the material that is used for the majority of other speaker cabinets can't do that either ! So what's the point in that ?
Just because both modules are down by 5 dB approx in the 200 Hz range doesn't mean that the summed response will have a dip of about this depth. If this were true a LR crossover wouldn't work either. To give a valid result the summed response has to be measured as well (while I can fully agree that the choice of crossover-frequency for a mono woofer is waaaay too high).
Just because B3$% uses a bad implementation of a 2.5" FR driver with paper cone doesn't mean that FR drivers with paper cones wouldn't work.
I once had the "pleasure" to attend a sales demo at a B3$% outlet in their home-country (north of Boston). It was quite interesting from a sales-technique point of view. 😉
Regards
Charles
While many of the facts given on the previously mentioned webpage may be true, some of them do not withstand technical scrutiny.
I can agree that plastics usually don't isolate EMC very well, but the material that is used for the majority of other speaker cabinets can't do that either ! So what's the point in that ?
Just because both modules are down by 5 dB approx in the 200 Hz range doesn't mean that the summed response will have a dip of about this depth. If this were true a LR crossover wouldn't work either. To give a valid result the summed response has to be measured as well (while I can fully agree that the choice of crossover-frequency for a mono woofer is waaaay too high).
Just because B3$% uses a bad implementation of a 2.5" FR driver with paper cone doesn't mean that FR drivers with paper cones wouldn't work.
I once had the "pleasure" to attend a sales demo at a B3$% outlet in their home-country (north of Boston). It was quite interesting from a sales-technique point of view. 😉
Regards
Charles
AM5....Slightly off topic!!
I was burgled in 1993
and (amongst the haul) the scrotes took my AM5 double cubes. I still have the sub, and use it to provide a little more bass for my stereo tv. Well, it's better that it sitting in the loft!!
Anyway, sure as eggs are eggs, the poor sap who bought those speakers in a pub carpark somewhere would, no doubt, have blown them. Hopefully it would have done some damage to his kit, too!!!
I am still waiting to come across a cheap pair on eBay or somewhere, so I can use the set up in the dining room, downstairs loo, or wherever.
I think it is safe to say that they are not much use by themselves, though.
Cheers
Jon🙂
I was burgled in 1993
and (amongst the haul) the scrotes took my AM5 double cubes. I still have the sub, and use it to provide a little more bass for my stereo tv. Well, it's better that it sitting in the loft!!Anyway, sure as eggs are eggs, the poor sap who bought those speakers in a pub carpark somewhere would, no doubt, have blown them. Hopefully it would have done some damage to his kit, too!!!
I am still waiting to come across a cheap pair on eBay or somewhere, so I can use the set up in the dining room, downstairs loo, or wherever.
I think it is safe to say that they are not much use by themselves, though.
Cheers
Jon🙂
Agreed on all points. I provided the link because it's the only one I'm aware of that has any info about Paulinator's XO frequency question.
I know the Acoustimass x-over contains so called loudspeaker protection elements which are in fact nothing else but small lightbulbs. They are connected in series with the cube speakers and act as a PTC resistor (like every lightbulb).
I suggest to use some of these to protect the small cube speakers.
Leroy
I suggest to use some of these to protect the small cube speakers.
Leroy
do him a favor and DONT use speaker protection... blow them, and allow him to get real sound for less money.
I had to do a re-foam on one of the two drivers in an Acoustamass bass module for someone a couple months back and the x-over in these is VERY simple. Half of the x-over was dominated by the tweeter protection light bulbs. The steep x-over of the bass module is a result of the 6th order bandpass box that Bose uses. If you really want to use those cubes, build a small bandpass box with two 4" LF drivers just like Bose uses. If the person you are doing this for really wants that Bose sound (you don't need any mid-range anyway, do you?) , this will be the only way to go. As far as the cubes, a x-over of around 200 to 250 Hz should do the trick. If you just run them from receiver though, they will probably blow pretty soon.
Cheers,
Zach
Cheers,
Zach
As much as I do believe in the "if it sounds good to you" mantra of thinking. Being a student reviewing the essay writing process, an acronymn lingers in my mind. SEX-State, Example, eXplain. So, the website aforementioned stating a fact then, providing an opinion without credible support has failed his proff thus far. Without any mathematics to provide the harmonic distortion or the amount of power required to push a cone to a certain excursion to produce x frequency. As far as I'm concerned this l'il feller needs to study some physics and provide viable proof because, I couldn't believe a word he says without such proof.
As mentioned previously, who is to say that the dip, when summed will result with a fairly flat response?
I know I'm not blind, but is that a line tapering off at an inaudible volume at say, around 18Khz.? Yup. Perhaps through Bose's theories that it isn't necessary to provide frequencies past 16Khz.? Perhaps, to give a light and warm quality to the HF sound? Now, the response of the centre channel isn't too hot though, maybe the R&D department settled on, 'The centre channel is for voices and few other things.' and ditched the sound after 13Khz.
Now to answer the question that began this thread. I wouldn't do it myself....hell no! It would be like adding a subwoofer to a Bose car system, something is primed for blowing up.
As mentioned previously, who is to say that the dip, when summed will result with a fairly flat response?
I know I'm not blind, but is that a line tapering off at an inaudible volume at say, around 18Khz.? Yup. Perhaps through Bose's theories that it isn't necessary to provide frequencies past 16Khz.? Perhaps, to give a light and warm quality to the HF sound? Now, the response of the centre channel isn't too hot though, maybe the R&D department settled on, 'The centre channel is for voices and few other things.' and ditched the sound after 13Khz.
Now to answer the question that began this thread. I wouldn't do it myself....hell no! It would be like adding a subwoofer to a Bose car system, something is primed for blowing up.
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