Printable View
I have a GPA-rebuilt 604c which I find lacks bass, compared to 604-8K's, when mounted in a similar-sized and ported enclosure (actually that of Tannoy Arden's fitted originally to HPD-385's). The spider is quite a bit stiffer, ie the cone harder to move by hand pressure, compared to two un-reconed 604C's.
Is it necessary to break-in a recone, and if so how?
Thanks,
Jon Archibald
Hi Jon,
Yes a recone requires the same break-in as a new driver. Did you get a remag also? The break-in is best done in free air with a tone generator but failing that, you can mount them, wire them out of phase and face them toward one another while you play some bass heavy music for a day or so.
Thanks for the reply Cal.
GPA did the job so it was remagged for sure. I played it today as I was doing paper work in my office, with the loudness on and the bass boosted a little. Sounds pretty nice in the Tannoy Arden enclosures, about the same size as a 620 cab, and they bolt right in.
I did have to put the gaskets on the rear of the flange though, since I could only surface mount them.
The port is rectangular, about 16 inches across by 3 inches wide and ducted to about 6 inches in depth, making for more acoustic loading than I think a stock 604C calls for. The Tannoy HPD-385 15-inch dual concentric speaker has much springier, ie more compliant suspension so I would guess it needs different port dimensions. Please correct me anyone if my attempt at being technical has bombed!
Jonny A.
PS Cal, if wiring them out of phase do you mean face the two 604 drivers up real close, like even bolted together? Sounds like it would really get the cone excursion really swinging, in synch but opposite, if you get my meaning. Great idea.
Are you guys SERIOUS - mounting them face-to-face?
Come on... ???
I can see none of my speakers were properly broke in....
:snickerpup:
Mounting them face to face usually results in a lower SPL in the room. So you can run your annoying break-in tones longer, louder.
That's all.
Blankets work, too.
Good Grief!
I now have images of Charlie Brown in my head :)Quote:
Originally Posted by Todd W. White
I think break in for a driver is kind of silly. I can't see the surround or spider needing to wear in. If they do, it can't be much, and in order for it to be a true break in, it would have to break down and then plateau. Otherwise it would just be a steady degrading of the material and sound.
I've seen people test speakers and state that there was no break in period. I've never really paid too much attention if anybody has posted pre and post break-in graphs. If there is a difference, I still don't see any point in breaking the drivers in....... just listen to it. It's not like its going to go from finger nails on a chalk board to beautiful music. It's not going to be that kind of night and day difference.
Cone drivers break in, of that I am sure. Fs and Vas will change, and some other parameters. I've measured it, so have many folks I know. I can provide measurements, if you like.
You're right tho that they do kinda plateau. Once they get loosened up, then they don't change a lot after that. It's no big deal. The surround and the spider flex and get more supple, that's all.
I always thought you just mount them in your enclosure and run some tunes through them for a couple weeks :2thumbsup: Good To Go
No, not necessary, I'll take your word for it.Quote:
Originally Posted by Panomaniac
I just don't see the point, unless you're going to measure the driver and then design a box around those measurements. Then it would make sense to reach that plateau. However, I'd question any break in method that would allow the cone to move excessively. It seems to me that it would be possible to work the driver beyond the point normally reached during playback and end up with equally off numbers as a driver that hadn't been broken in. Please understand that I'm just speculating. I don't have intimate knowledge of the characteristics of the relevant materials.Quote:
You're right tho that they do kinda plateau. Once they get loosened up, then they don't change a lot after that. It's no big deal. The surround and the spider flex and get more supple, that's all.
IMO "panomaniac" is right.
Loudspeakers are electro-mechanical devices, and like any other mechanical device, they have a graph which shifts to a different value after few hours of initial use, which then continues with it for a longer steady period, and again changes that when they are ready to die. So breaking-in really does help in serious/professional cases. I personally always do a breaking-in thing with new drivers. Otherwise everything else suffers while designing something new.
There is also another side to it.....
The coil assembly also gets a kind of a heat/baking treatment which increases its life span, and also slightly raises its high-end power handling capacity. Most pro/studio users always benefit from this. Ofcourse many pro manufacturers always ( or rather should ) heat-treat the motor assembly prior to its assembly.
Regards
Aditya
That's exactly the reason to do it. As I see it (born out with tests), it only takes about 30 seconds at xMax to get ~as far as it's gonna go. It'll take that much to have the same effect the next time you use them, getting less with frequent use. Even old drivers are best measured after being fully flexed a bit.Quote:
Originally Posted by Audio_by_Goodwill
That's it? I understood it to be something people would set up and leave running for hours. Maybe that's just over exuberance on their part, although, you did specify xmax, so maybe they aren't pushing them that hard, and therefor taking longer.Quote:
Originally Posted by bfish
the way i understand it..the original 515, pre-b, took quite a bit of breaking in due to the spyder being very stiff at first, but once broken in a bit they are amazing
When I got my reconed 411-8A's back from GPA, I measured the TS parameters. They were not close to what Altec spec'd......so I set one on the bench and ran it with a 10 hz sinewave, about a 1/4" excursion for 2 days.
Re-measured...no difference.
I think driver break-in is bs. Sorry.
Ron
Actually you are the only person I know who has measured, run break-in, then measured again and found no difference.
Your procedure certainly seems right.
Strange....
The funny thing was, the TS paramaters measured closer to a 416 than the 411, so I designed the enclosures accordingly. I used them as sub woofers, vented. The orig 411 was meant to be a sealed box woofer. I went with 8 cubic feet with 6" round ports about 6" long. I tuned the boxes to 20hz. Worked great.
Mine were the first pair of 411 that GPA did, they may have different parts now.
Here is a photo of the subs with the duplexes.
http://www.hostboard.com/forums/hbmc...2010/03/18.jpg
Simple MDF, well braced.
BTW.....probably the best sound from Altecs I have ever made........
Ron
Dont forget the break in period for the monster speaker wire.... Keep it under 10 watts for the first half hour.
:coffeedrinker:
Here's what Klippel (the guys that make the test sytems mfrs & engineers use...) has to say;
http://www.klippel.de/download/bin%5...easurement.pdf
The meat is in the last 2-3 pages (complete w/graphs & charts). Note the reference to non-linearities due to compliance changes... when "broken in", the suspension actually becomes stiffer at travel extremes, but more compliant at lower excursions.
But it's just a brief change... at times on the order of seconds. Therefore, it's not a permanent thing like we normally think of as "break-in". I like to think of it more as "warming up".
Added;
For those that never push their woofs anywhere near Xmax, it's a non-issue. ;)
Ahhhhh..... So we only needed to break in our woofers!Quote:
Originally Posted by bfish
Quote:
Originally Posted by Nipper
Well, the topic is "Do recones need a break-in period". What else get's reconed? :confused:
To be fair, anything with a typical spider.
But...
I'm not saying anyone should breakin their woofers for listening purposes, only for measurement and design. Actually, since a suspension that has loosened up is generally less linear than one that hasn't, why would anyone do it at all...:D
Dont tell anyone but I had a set of Infinity speakers once and they had a designated midrange speaker. ;)Quote:
Originally Posted by bfish
Please dont take me to serious on this topic Bfish.... Just having fun. :D
Ron, I'm curious about what Bill is providing as a 411 recone substitute .Quote:
Originally Posted by RonSSS,RonSS
I realize your 411(s) were the first pair that Bill did ( now a few years ago ) .
Did you by chance keep a record of their TS parameters ( as measured back then ) ?
Specifically, I'm wondering if you measured BL, MMS and/or ( attempted to get an accurate ) VAS ?
thanks <> EarlK