OK - a little humor (?) there - but I now seem to have a dilemma. I was dusting and furniture-polishing the B&W 705s yesterday, and happened to shine a flashlight into the ports - just to check any possible dust layer. Instead of dust I saw that one port was open and I could see the crossover panel on the back side. The other port was blocked by the white "stuffing" in the speaker enclosure. Now the "clean" port was on the speaker I'd worked on and replaced the crossover. The other speaker had the port-blocking stuffing. Hmm. . .not good, said I. Now - question for you who are much better informed than I. Should the ports be blocked by stuffing? And just how much stuffing should there be in a ported enclosure? I've e-mailed B&W, but no reply yet. I've read that too much stuffing will kill bass response, and, indeed, the speaker with the "stuffed port" has much less bass response than the other one. Some help -information-suggestions, please? Respectfully. . .LarryR
"I've read that too much stuffing will kill bass response, and, indeed, the speaker with the "stuffed port" has much less bass response than the other one."
Well, let's think about this. Are the two speakers in the same position in the room? Is one speaker on the side of the orchestra where bass instruments typically reside? How did you determine this "fact", Larry? How often do you dust the inside of your ports?
I determined this fact by siting the two speakers out in front of the gear cabinet - about three feet apart. Then I switched out the cables L-R so that I could hear strings(hi) and cellos/brass(lo) through the speakers, one at a time. In each case the R-hand speaker (with the stuffing that had apparently fallen down so that it blocked the port) had much less bass response. BTW - B&W says that there should be NO stuffing visible when looking into the port - so I guess I have to go in and put the stuff back up inside the cabinet, where it apparently once was. SIGH Respectfully. . .LarryR
Forgot to add: B&W reminded me that these speakers are sold with foam "port plugs" that can be inserted to reduce bass levels. I guess the stuffing is doing the same thing.
In general where the stuffing resides in a vented speaker is not critical. However, some designers do have a scheme for how the stuffing is distributed to minimize turbulence and port noise. Depending on the density of the material shoved up against or into the port you can go from an aperiodic loading similar to that used in the original Dynaco A-25's or all the way to a sealed enclosure. Either of those loading schemes would alter the resonant frequency of the system. I thought I reminded you back on another thread not to change the distribution of the stuffing.
Message received, Jan - but if you read my posting a bit closer you'll find that the "offending" speaker is the one which I did NOT dig into or change internally at all. The one in which I changed out the crossover does not show the stuffing in the port opening - a condition that B&W says is normal, and that I should not see it when looking into the port. Respectfully. . .larryR
I don't have much to add, only that on my old Tannoy F2 I saw stuffing in both ports. I wasn't expecting that and was concerned for a bit. But the speakers sounded great so I forgot about it.
Larry, is it possible that the offending speaker is actually the speaker that sounds the way B&W intended it to? Specifically because of the stuffing in the port? And that the one you fixed should have the same stuffing distribution, but in fixing it you altered that distribution? Stuffing may well reduce bass, perhaps by design, so that there isn't too much bass. My F2 were definitely not bass lite, despite the stuffing they had in the ports.
The stuffing is fairly low density and shouldn't interfere with anything. Unless, of course, you packed and 'compressed' it when working on the internals. Is the stuffing crammed into the port or is it light and fluffy?
OK, ev-body. For the third time, please. The speaker with the visible packing is the one which I did NOT open up. I replaced only the tweeter, which is in a separate, external, housing. B&W says I should NOT see any packing - so obviously it has become dislodged from wherever it was before. The packing material is very dense - like dacron fiber fill, but I'm not sure what it is - not fiberglass, for sure. I guess the only thing to do is to open the cabinet and try to replace the packing similar to the fitting I did with the other speaker when I replaced the crossover. We'll see. . . Respectfully. . .LarryR
Next time buy sealed speakers? Or speakers with an external crossover. I think the problem here, to the extent that there IS a problem is that the speakers are not perfect, Larry is persistent and quite detail oriented. Add in good hearing and a touch of 'I want it to be right' and you have a project. Once fixed, I expect 'em to go for a while without needing attention.
Once fixed...they appear to need fixed again. That's the problem Leo. Not a problem if you don't mind...big problem if you do. I've owned a number of speakers for years and never had the number of issues Larry has with his. However, once you replace the drivers, crossovers and restuff 'em I guess there ain't much more to do...lol!
Oh, Art, you don't know the half of it, my friend. Mer says I was put on this earth to be the brunt of every cosmic cruel joke. If I buy something, it will surely break. Last month I bought an ultra-violet sanitizing light for Mer. I put in the batteries, tested it, and handed it to her. An hour later it literally melted down and had to be sent back. The distributor said that "had never happened before." Last week I went out to buy a "whistling" tea kettle. Brought it home, set it on the stove. No whistle. Took it back. The clerk said "nobody's ever brought back that model." Got new Lexan hurricane panels for our condo windows yesterday. Unbreakable, right? This morning the sun hit the kitchen window and somehow expanded the panels in their mounting, and one of them shattered. Unbreakable? Six months after we bought our new Samsung LCD flat panel TV the plastic case around the screen suddenly split wide open. Got a new toaster the first of the year. It burned the first piece of toast and wouldn't shut off. The new Oppo 83SE DVD player that I got developed a dropout in the 7.1 cables. Would only play 2-channel. I sent it back, but the shop said there was "nothing wrong with it." They sent me a new one, which promptly developed some short circuit in the HDMI cable and blew the breaker in the TV set. Changed out the HDMI cables and all is -temporarily - OK. For today, anyway. Got a new FM radio for Mer's studio. It lasted a week. Mer is back with her old one. Are you seeing a pattern here? Heck, my problems with the B&Ws are just the icing on the cake of life. . . Saturday - when Mer is away teaching rich women how to make pretty glass art I'm going to do "surgery" on the B&Ws - check the stuffing very carefully - and try to get them filled in the same places, and with the same amount of white gunk. SIGH. Then I'm going to make a very large martini, sit down in the middle of the living room floor and mope. . .If the speakers don't sound "better" (sorry, Jan) after that I'll make a second martini. That should help. Sunday I'll be 74 - which is reason enough for depression down here in Swampville. . . . .S I G H Respectfully. . .LarryR
Lar, my wife says the same of me. However my luck has been much better since I started buying from my friends at Eugene HiFi. Still, my speakers were usually good. However you may remember I went through a number of speakers to finally get a good set of Wharfedale Diamonds. Stuff happens, Lar. I believe that you should feel free to repair your speakers or replace them without ridicule. There is no right or wrong, just whichever works for you. You (and Mer) are the captain of the ship, steer man steer!
Serially, I've not heard of a run like Larry's in a long time.
My wife is strictly lo-tech. The highest form of tool anyone in her entire family uses is the butter knife. But, nobody just LOOKS at stuff and has it break.
Leo,my friend - me thinks ye could be on to sumpin' here! Hmm. . . And then there is the little nagging problem: I have to keep Mer at least six feet away from the receiver if I'm listening to FM. If she walks by the set any closer than that - the FM channel changes, usually to just static. Really. . . As I say, Leo - ye might verily be getting close to the answer. GRIN And with respect. . .LarryR
Art - there IS no final solution - at least not a legal one! GRIN Yeah, Nuck, but I've found that those danged floors get lower and lower as the years go by! FLASH; Just finished SURGERY on the B&Ws - and what I found rather confounded me. I set them on a (padded) table, side by side, and then compared the "stuffing" and the methods used to fill the cabinets. The "white gunk," thanks to Mer, is batted dacron fiber, comes in rolls about an inch or so thick. To fill the cabinets B&W folds those bats over and over to fit the open spaces. I'd carefully followed the "pattern" I discovered when I opened the one to replace the crossover. That batting was just where I'd put it, with the bottom third of the cabinet open and the front-firing port plainly visible. But - but - the second speaker presented a different picture. First, there seemed to be less batting in the cabinet, so pulled out the dacron from both speakers and laid them side-to-side. Yep, the speaker I'd worked on had about 30% more batting. No wonder I had a tussle getting it all back in! OK - now I got down to the second layer of batting - the speakers, BTW, were lying face-down on the table. Now I found the source of the problem The batting that comes up against the woofer had for some reason come un-rolled on one side, allowing one end to seal off the port, and the other end to rest against the speaker cone! Aha! Took the batting out, re-folded and rolled it and stuffed it back where the internal cabinet bracing called for it to stay. It did. So far, anyway! Then I matched up the top-layer batting so that each speaker had the same amount, and stuffed that back into place. Tired. . . . Crossed my fingers and plugged everything in. . .voila! The sound was much more "even" coming from the speakers, and the "offending" speaker was putting out a lot more sound from the woofer. Obviously, that batting should NOT have come in contact with the cone! I have no idea how it unraveled. Well - everything is humming along in the living/listening room now, and yet it's too early for a celebratory martini. I think. . . Respectfully. . .LarryR
No, Jan - I have no way of knowing whether it was worked on before I bought it - used - from a chap up in New Jersey. He said they'd been used for less than a year, but otherwise he said nothing about any changes made to them. SIGH. I've always wondered, though. . . .given all the problems I've had. Respectfully. . .LarryR PS - long ago lost the chap's name/number, so couldn't contact him.
Which speaker had the correct amount of batting? That's one of the things DIY guys do last.....decide on how much stuffing. To 'assume' one speaker was untouched and therefore correct is a reach. But one IS original? Speakers now match?
Well, I "finally" got a callback from my very old audio-sales friend in Chicago. Dealt with him for many years, and introduced him to his third wife, which actually worked out very well! (whew!) Anyway - I quizzed him about the B&W, and he said that he'd try to get an answer to the "stuffing" questions I raised. Turns out he got to some mope at B&W who does know about such things, and, as he's been dealing with B&W for thirty years, my friend's call carried a bit of weight. He said the wadding should be "loosely packed," and not compacted. OK for one, not for the speaker I'd opened. And no, I had NOT added any stuffing! Didn't even know what it was at first. He gave me the factory numbers. As I'd carefully measured the batting in both speaker compartments, I knew which one was "off." Actually, the speaker I'd worked on was "off" by quite a bit. The smaller compartment had 5 inches too much, and the larger one had a whopping 16 inches too much batting! And it was packed in TIGHT. I had trimmed the batting in the second speaker back to match the speaker I had never opened - the one with the visible stuffing, which was the one within tolerance after all. So was this a break-down in quality control? I'll never know - but now both speakers have equal Dacron innards, and the sound is way, way more balanced. Respectfully. . .LarryR
Oh, yes - one more point. Y'all know that I've replaced both tweeters, so if you aren't very familiar with B&W 705s you might think I've had to open the cabinets. Not. The tweeters are mounted in their own, external, "pods," and replaced by opening the pods, not the cabinet itself. LR