sam9 said:
Yes, but those were the days when people put their speakers in the corners. It was only later that the benefits of pulling them out into the room became obvious. Right now I have my speakers 8' from the back wall and 5' from the side walls. Even the AR, Advent, KLH would have benefited from proper placement with respect to room surfaces. At least Bose offered placement suggestions with the 901s. Nobody else did, as I recall. I agree that the 901 made a good party speaker but it had no illusions to accurate reproduction.
I don't recall that he mentioned specifically that the surrounds were rotted, although they most likely are. I suppose my views on foam speaker surrounds are well enough known that there's no need to go into that here. In short--yuck!
A simple visual inspection will tell the tale on the surrounds. Whether he has someone repair the drivers or does it himself is another matter.
Me, I'm with the earlier post that mentioned lighter fluid, but then it's been a long, hard day and perhaps I'm in a worse mood than I should be when bringing up the delicate topic of trashing Bose speakers when the fellow has made it his life-long dream to lay hands on them. Sigh. Someone find my diplomacy pills--I fear that I need them.
The post on bottoming the cones is reasonable also, especially given the boost the 901s need to even pretend to have real bass vs. the amount of low end in your average shoot-'em-up movie. Note that this amounts to a penalty paid with amplifier power. A speaker that had something more like flat response would not chew up amp power like that, leaving more leeway before clipping.
Uh, let me do my best to say this politely: Please save your money. Do not put it into the Bose in any way. Use it to buy another brand of speaker (new or used, your option) or to build a decent DIY project. There are scads of speaker projects out there that will provide better sound quality for less money.
Hype and advertising do not a decent speaker make. They weren't even good in the '70s and things have come a looong way since then.
Grey
P.S.: Better than Advents? Egad. I'm biting my tongue.
A simple visual inspection will tell the tale on the surrounds. Whether he has someone repair the drivers or does it himself is another matter.
Me, I'm with the earlier post that mentioned lighter fluid, but then it's been a long, hard day and perhaps I'm in a worse mood than I should be when bringing up the delicate topic of trashing Bose speakers when the fellow has made it his life-long dream to lay hands on them. Sigh. Someone find my diplomacy pills--I fear that I need them.
The post on bottoming the cones is reasonable also, especially given the boost the 901s need to even pretend to have real bass vs. the amount of low end in your average shoot-'em-up movie. Note that this amounts to a penalty paid with amplifier power. A speaker that had something more like flat response would not chew up amp power like that, leaving more leeway before clipping.
Uh, let me do my best to say this politely: Please save your money. Do not put it into the Bose in any way. Use it to buy another brand of speaker (new or used, your option) or to build a decent DIY project. There are scads of speaker projects out there that will provide better sound quality for less money.
Hype and advertising do not a decent speaker make. They weren't even good in the '70s and things have come a looong way since then.
Grey
P.S.: Better than Advents? Egad. I'm biting my tongue.
Okay, I have a pair of 901 Series IV speakers at the ready to show you that it is nearly impossible to get them to bottom out. I HIGHLY doubt they are bottoming.
Since, all 9 drivers are connected in series, the voltage is divided between them so any EQ would be divided between the drivers. This is why Bose was allowed to get away with such a rigorous EQ.
The man may be hearing the effects of full-range IMD. But, with the 901s it seems that this is less apparent than with other full-rangers.
It takes a lot of juice and the right type of music to reach bottoming levels, but less juice to reach all-out IMD.
Since, all 9 drivers are connected in series, the voltage is divided between them so any EQ would be divided between the drivers. This is why Bose was allowed to get away with such a rigorous EQ.
The man may be hearing the effects of full-range IMD. But, with the 901s it seems that this is less apparent than with other full-rangers.
It takes a lot of juice and the right type of music to reach bottoming levels, but less juice to reach all-out IMD.
The foam surrounds are not just subject to visual inspecton. They might look alright, but poke them a little and they may tear.
If you think the foam surrounds are the problem, here is the link to get the repair kit from Parts Express, $40, :
http://www.partsexpress.com/webpage.cfm?webpage_id=3&SO=2&&DID=7&CATID=49&ObjectGroup_ID=373
Rotted surrounds can indeed cause voice coil rub, since the cone/voice coil assembly is suspended by the spider and surround. Lose one and voice coil rubs against the interior pole piece.
If the cabinets are in good shape and you like the Bose, and you are convinced it is the surrounds, then you should refoam the speakers. If nothing else, you might have something valuable for resale, should you decide that better speakers are out there.
PS: If you are refinishing the cabinet, do not use steel wool if the speakers are mounted in the cabinet. The magnet draws the airborne steel particles toward it, and the voice coil gap can get ruined.
If you think the foam surrounds are the problem, here is the link to get the repair kit from Parts Express, $40, :
http://www.partsexpress.com/webpage.cfm?webpage_id=3&SO=2&&DID=7&CATID=49&ObjectGroup_ID=373
Rotted surrounds can indeed cause voice coil rub, since the cone/voice coil assembly is suspended by the spider and surround. Lose one and voice coil rubs against the interior pole piece.
If the cabinets are in good shape and you like the Bose, and you are convinced it is the surrounds, then you should refoam the speakers. If nothing else, you might have something valuable for resale, should you decide that better speakers are out there.
PS: If you are refinishing the cabinet, do not use steel wool if the speakers are mounted in the cabinet. The magnet draws the airborne steel particles toward it, and the voice coil gap can get ruined.
To the Bose Haters: I'll get these fixed and if I don't like them, I'll sell them. Someday (hopefully in the not-too-distant future) when I can afford to purchase my own system, I'll look into other stuff and decide then if Bose is all it's cracked up to be or not. Untill then, it's either fixing the 901's or using that money on a boombox or cheapo computer sub+satellite system, which I think everyone can agree will not sound as good as the Bose 901's.* Alas, that is the budget I'm working on in the here and now.
Quick question: how long does this kind of job take? Keep in mind I've never cracked these speakers open before, much less done a refoam job on them.
Thanks for all the input.
-Mark
*actually, if anyone disagrees with that statement, speak up!
Quick question: how long does this kind of job take? Keep in mind I've never cracked these speakers open before, much less done a refoam job on them.
Thanks for all the input.
-Mark
*actually, if anyone disagrees with that statement, speak up!
Whether the drivers are in series, parallel, or some combination of the two makes absolutely no difference as to bottoming.
Actually, I've heard some computer sub/sat systems that I'd consider superior to Bose 901s. The caveat is that I wasn't paying attention to the make and model. Sorry. The Bose will probably play louder than a computer system. Whether that's important to you is up to you. I know there was a time when volume was a lot more important to me than it is now. If I had to, I could live with a system that was limited in volume but gave me the quality I wanted.
Life is full of choices. Sometimes they're no-brainers. This one isn't that clear-cut. The 901s are, shall we say, limited. If they were the ultimate speaker, it would indeed be a no-brainer: Fix 'em and be happy. Sadly, they aren't on that level. That puts the burden on you. It's your dollar, and you'll have to decide how best to spend it.
I know it's a jolt to read that Bose is not all that great. I remember having a Panasonic all in one system back in the eary seventies. I thought I was something! The reality was that it was barely on the mid-fi scale, probably more low-fi. That was a bitter pill to swallow. Things have gotten better since, though.
Toss out a dollar figure that you'd be willing to spend. I'd be surprised if kelticwizard and some of the others couldn't suggest a few project speakers that would be worth at least looking at.
Grey
Actually, I've heard some computer sub/sat systems that I'd consider superior to Bose 901s. The caveat is that I wasn't paying attention to the make and model. Sorry. The Bose will probably play louder than a computer system. Whether that's important to you is up to you. I know there was a time when volume was a lot more important to me than it is now. If I had to, I could live with a system that was limited in volume but gave me the quality I wanted.
Life is full of choices. Sometimes they're no-brainers. This one isn't that clear-cut. The 901s are, shall we say, limited. If they were the ultimate speaker, it would indeed be a no-brainer: Fix 'em and be happy. Sadly, they aren't on that level. That puts the burden on you. It's your dollar, and you'll have to decide how best to spend it.
I know it's a jolt to read that Bose is not all that great. I remember having a Panasonic all in one system back in the eary seventies. I thought I was something! The reality was that it was barely on the mid-fi scale, probably more low-fi. That was a bitter pill to swallow. Things have gotten better since, though.
Toss out a dollar figure that you'd be willing to spend. I'd be surprised if kelticwizard and some of the others couldn't suggest a few project speakers that would be worth at least looking at.
Grey
Bill Fitzpatrick said:
Well, I'm from those days and we didn't put our speakers into corners unless they were tiny and needed the bass boost. 901s were easily the best speakers of their day because they spread the sound around, and gave you a sense of being enclosed in the music, as opposed to having it beamed at you. Time does march on and they are no longer the cutting edge, but that doesn't mean we should diss them. They were the `55 Chevies of speakers and we should respect them for that, instead of ripping them because the company later made huge profits from the AM series.
Bill Fitzpatrick said:
According to this replacement parts website, each Bose 901 4.5" driver is 1 ohm:
http://www.oaktreeent.com/Bose_Speaker_Parts.htm
(Scroll about halfway down the page).
Interesting, the fellow at this website claims only a 60% success rate with refoamed Bose drivers passing the frequency response test of the original. Hmmm.
The Bose 901 was never a competitive speaker for high fidelity use. Spraying sound around a room indiscriminately is not hi-fi (the paper Bose himself wrote on the effect was very badly flawed). Clearly some people fell for the effect, but it's not a reasonable way to recreate a recording. I believe the term party speaker was used above. That might be a better application, in that imaging isn't an issue, only volume.
Grey
Grey
I really don't see where it would be a particularly high volume speaker either, frankly.
There are nine 4.5" drivers that are supposed to have a surface area equal to that of a 12" driver. However, I haven't seen anyone argue that these 4.5" drivers have a throw anywhere near that of a 12" driver. Does anyone know of a 4.5" driver with an excursion of (+ or -) 0.25 in, or 6 mm? For that would be the linear excursion for a decent 12 incher in the seventies. Excursions have gone up since then.
The original 901's were sealed, so there was no excursion relief for the 4.5" drivers. Later models came out with some fancy name, but which I suspect gives no more excursion relief than the bass reflex. But most speakers today are reflex, so there is no advantage there.
Plus, I doubt the 4.5" speakers have the excursion of even the 70's 12 inchers.
So, where is this big volume capability coming from? If the speakers play loud enough for you, and they might, fine. But so will most 12 inchers on the market.
There are nine 4.5" drivers that are supposed to have a surface area equal to that of a 12" driver. However, I haven't seen anyone argue that these 4.5" drivers have a throw anywhere near that of a 12" driver. Does anyone know of a 4.5" driver with an excursion of (+ or -) 0.25 in, or 6 mm? For that would be the linear excursion for a decent 12 incher in the seventies. Excursions have gone up since then.
The original 901's were sealed, so there was no excursion relief for the 4.5" drivers. Later models came out with some fancy name, but which I suspect gives no more excursion relief than the bass reflex. But most speakers today are reflex, so there is no advantage there.
Plus, I doubt the 4.5" speakers have the excursion of even the 70's 12 inchers.
So, where is this big volume capability coming from? If the speakers play loud enough for you, and they might, fine. But so will most 12 inchers on the market.
1. The 901s drivers are measured in series. I am an Electrical Engineering student and have been building speakers for 4 years, don't believe me-fine. I know what series looks like. I also again, have the 901s at disposal for proof.
2. I think Bose gave the 901s an "acousti matrix" enclosure or something rather. There was a port for each of four drivers in the rear and one port for the front loudspeaker. They were 'cantilevered' ports and produce very little turbulence.
3. They don't play that much louder than one channel of my proto type speaker right now. In a medium-sized and open room, I had one 901 playing to about 103-106dB. on 100W RMS. My prototype speaker will reach 103dB. but I have yet to reach 106ish. Oh, and my speaker isn't IMD'ing like the 901 and sounds 'xoverless'. Thank you series xovers!
4. The 901s are a fun speaker to listen to, but I think it is time for Bose to stop milking it and come up with something new. Dr. Bose has got have better ideas for reproducing lifelike sound by now...screw profit margins, build the industry another 901-like revolution. (same impact)
2. I think Bose gave the 901s an "acousti matrix" enclosure or something rather. There was a port for each of four drivers in the rear and one port for the front loudspeaker. They were 'cantilevered' ports and produce very little turbulence.
3. They don't play that much louder than one channel of my proto type speaker right now. In a medium-sized and open room, I had one 901 playing to about 103-106dB. on 100W RMS. My prototype speaker will reach 103dB. but I have yet to reach 106ish. Oh, and my speaker isn't IMD'ing like the 901 and sounds 'xoverless'. Thank you series xovers!
4. The 901s are a fun speaker to listen to, but I think it is time for Bose to stop milking it and come up with something new. Dr. Bose has got have better ideas for reproducing lifelike sound by now...screw profit margins, build the industry another 901-like revolution. (same impact)
Okay, so the Bose delivered more SPL into a room than an Open Baffle with two long throw 9 inch woofers on it, (the Illusion 804's), and one 6.5 open baffle midbass with tweeter-both Seas.
At least on 100 Watt input.
I'm a little surprised, although Open Baffles tend to be less sensitive than boxed speakers.
How wide was the Open Baffle with the Seas 6.5 incher on it?
Where are your crossover points? These may affect the sensitivity of the Open Baffle.
At least on 100 Watt input.
I'm a little surprised, although Open Baffles tend to be less sensitive than boxed speakers.
How wide was the Open Baffle with the Seas 6.5 incher on it?
Where are your crossover points? These may affect the sensitivity of the Open Baffle.
GRollins said:
Not a "reasonable way to recreate a recording?" Oof. Clearly some people don't get it. There's more than one way to judge a loudpeaker and enjoy its output. If you don't like it how a good quality dispersion speaker sounds, fine. I could care less. But, please, don't make blanket statements insulting people you don't know about things you know nothing about.
A good dispersion speaker setup properly provides a nice, full sound that I prefer over a narrow angle, thin sounding beamer. The dispersion comes with a cost, of course, but I've always been willing to sacrifice some soundstage and reproductive accuracy for the more life-like ambience that dispersion and diffusion can give you.
And furthermore . . .
Reproducing recorded music is something of a non sequitor. Can't be done with a loudspeaker, no matter how much you spend on your output devices. The dynamics just aren't there. The dispersion concept is just another attempt at compensating for that, much like reverb and four-channel. And that is simply something I prefer. If others don't prefer it, that's okay with me. I just wish they'd dismount from their high horses.
Reproducing recorded music is something of a non sequitor. Can't be done with a loudspeaker, no matter how much you spend on your output devices. The dynamics just aren't there. The dispersion concept is just another attempt at compensating for that, much like reverb and four-channel. And that is simply something I prefer. If others don't prefer it, that's okay with me. I just wish they'd dismount from their high horses.
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