Sensitivity Ratings

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oneinthepipe

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Re: Sensitivity Ratings
« Reply #80 on: 31 Jan 2009, 11:06 pm »
BRM:

Can you take a photo of a plastic-clayed speaker frame?  I will probably want to try this too, but being the chicken that I am, I would prefer to see what you did rather than stick plastic-clay in the wrong places.    

I hope that this wouldn't be an imposition.   :D

BTW, Jim, does this only void the warranty if we tell you about it?    :nono:

Big Red Machine

Re: Sensitivity Ratings
« Reply #81 on: 31 Jan 2009, 11:34 pm »
You can't put too much on for a couple reasons:  need to clear the hole on the way back into the cabinet, can't glob it on the rear spider.  Although that metal ring around the spider was tempting to try.






DMurphy

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Re: Sensitivity Ratings
« Reply #82 on: 1 Feb 2009, 01:49 am »
Hi    Glad I'm not the only one playing with clay.  Just to make sure you're following good practice--did you and your 12-year-old compare the speakers before the mod?  And do you have a mono switch?  You obviously can't tell too much if you're listening to different channels of stereo recording.  I'll put a stop to this clay thing, I will.   Crossovers are the only things that matter.   :nono:

drab

Re: Sensitivity Ratings
« Reply #83 on: 1 Feb 2009, 01:55 am »
You should only use grey clay, everyone knows that green will "color" the sound.  :wink:

oneinthepipe

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Re: Sensitivity Ratings
« Reply #84 on: 1 Feb 2009, 03:15 am »
BRM:

Thank you for the photos.

Just on those parts of the frame?   

Hmm, I might be able to do that. How many pounds of clay is needed for (4) drivers? 


Big Red Machine

Re: Sensitivity Ratings
« Reply #85 on: 1 Feb 2009, 01:53 pm »
1/2 pound - 2 butter sticks worth

I think the woofers are worth trying, although very difficult to take out and manhandle.

HerculePirate

Re: Sensitivity Ratings
« Reply #86 on: 1 Feb 2009, 03:16 pm »
BIG RED

Sent you a PM and a email...
please chk and respond....THanks a lot

HP

R Swerdlow

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Re: Sensitivity Ratings
« Reply #87 on: 1 Feb 2009, 07:34 pm »
Big Red

Thanks for the photos… and they shall be known by one and all as the Salk GumbyTowers.


grenamc

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Re: Sensitivity Ratings
« Reply #88 on: 1 Feb 2009, 08:54 pm »
Now the whole time I'm wrapping green clay around this midrange frame I'm thinking this is the sickest joke Frank has ever played on us.  Who is gullible enough to try this, photograph it, and then tell about it!! Oh the shame!  Oh the horror!!

DAMNED IF THERE WASN"T A DIFFERENCE _ IMMEDIATELY!!


Luckily I had my 12 year old with me (he was bored and has been shadowing me - trying to irk me into giving him his Xbox controllers - it worked).  He heard it as well.

I put clay on one speaker and then we ran the balance back and forth side to side to see if we heard anything.  Sure enough, the clay speaker wasn't as bright as the other.  So is bright bad or good?  Is quieter bad or good?  I wasn't sure.  I put him in the sweetspot and he said it was brighter (non-clayed speaker).

So okay, I'll modify the left one now.  Yep, it quieted down as well (less bright).  It might be that the brightness was actually some sibilance now tamed.

So now I'm doing some listening to see if I actually like the "new" sound.

Jury's still out.  But there is an impact.  Damn Frank! :bowdown:

Hmm, this fascinates me. Especially the part where your HT3s became a bit warmer/less bright. Possibly more neutral?  I look forward to more impressions and information.

-Michael

funkmonkey

Re: Sensitivity Ratings
« Reply #89 on: 1 Feb 2009, 09:50 pm »
Here's a question along the lines of the clay pack (I think)...   :scratch: Has anybody tried supporting the magnet side of the speaker, thereby removing stress on the basket (or spider, not sure of the difference between those two parts or if they are indeed the same).  Could be a vertical steel element that the magnet sticks to, or a more mechanical connection attached from behind, solidifying the connection of driver to cabinet.  In a perfect world only the cone itself (and voice coil) should be moving or vibrating, right?  Or is there a desirable effect from letting the speakers "hang" on the front baffle (other than ease of attachment)?

I am no speaker designer (yet  :wink: ), but I am trying to learn and understand as I go...  So, I apologize if my idea seems silly.

Cheers.

DMurphy

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Re: Sensitivity Ratings
« Reply #90 on: 2 Feb 2009, 02:37 pm »
I remember an article about bracing the magnet with a rod support to the rear of the cabinet.  Of course, that will transmit vibrations to the cabinet, so the trick would be to damp those out at the rear connection.  I suspect we'll give all of this a look see when we get a little further along on the HT4. 

carusoracer

Re: Sensitivity Ratings
« Reply #91 on: 2 Feb 2009, 02:50 pm »
You can't put too much on for a couple reasons:  need to clear the hole on the way back into the cabinet, can't glob it on the rear spider.  Although that metal ring around the spider was tempting to try.







Pics did not come through? I will try the link...

WGH

Re: Sensitivity Ratings
« Reply #92 on: 2 Feb 2009, 03:31 pm »
I remember an article about bracing the magnet with a rod support to the rear of the cabinet.  Of course, that will transmit vibrations to the cabinet, so the trick would be to damp those out at the rear connection.  I suspect we'll give all of this a look see when we get a little further along on the HT4. 

I braced the magnet to the rear wall on my old JBL L100's a long, long time ago with very positive results because even with a 12" woofer the JBL's did not pump out the bass like I thought it should and needed a lot of bracing to control cabinet resonances. The woofer brace made for a more controlled punchy sound. The cabinet back of the original cabinets was reinforced with another layer of 3/4" particleboard for a total back thickness of 1 1/2". The JBL's are in daily use in my shop if anyone cares to stop by for a listen. Tucson is very nice this time of year.

Here is a photo of a VSA speaker with modeling clay I did in August '07. Yes, it makes a positive improvement. The housing around the magnet also rang like a bell when tapped so I wrapped the housing with some left over VB-2 vibration damping material from Parts Express.



Wayne

TomW16

Re: Sensitivity Ratings
« Reply #93 on: 2 Feb 2009, 07:00 pm »
I don't remember the vendor's name but I purchased the steel plates through eBay.  They cut them to the dimensions you specify.  You would think that shipping would be prohibitively expensive, however, USPS has a flat rate for anything that can fit into their shipping box (~$9.00).  The postal delivery person said that we definitely got our money's worth noting the weight of the 2 steel slabs that were shipped.

Cheers,
Tom

Good heavens.  You look normal.  How did you get into this thread?

I can't be that normal, I put a steel plate in my speaker  :wink:

Quote
Quote
I designed my speakers cabinets with a 1 inch thick steel plate (~40 lbs) to go between the top cabinet (containing the midrange and tweeter) and the woofer cabinet.

That is a killer cabinet.  It looks almost as good as Jim's!

Bob

Thanks Bob.  I haven't seen Jim's cabinets in person but from the pictures and the rave reviews, I believe that Jim's cabinets are a notch above mine.   I'm not the most patient person so I went with automotive primer, paint and clear coat since you can put many coats on in a day.  Jim hand rubs his finishes out with curing time between.  The pictures of Jim's speakers look stunning and I understand that the pictures don't do them justice.

Cheers,
Tom

Where did you get the steel plates?  I've been thinking about this or just getting thick marble or granite plates cut and doing the same thing with my speakers.  I know where to get the granite but not steel.  That's a good idea!



Biscuit

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Re: Sensitivity Ratings
« Reply #94 on: 2 Feb 2009, 11:58 pm »
I don't remember the vendor's name but I purchased the steel plates through eBay.  They cut them to the dimensions you specify.  You would think that shipping would be prohibitively expensive, however, USPS has a flat rate for anything that can fit into their shipping box (~$9.00).  The postal delivery person said that we definitely got our money's worth noting the weight of the 2 steel slabs that were shipped.

Cheers,
Tom

Good heavens.  You look normal.  How did you get into this thread?

I can't be that normal, I put a steel plate in my speaker  :wink:

Quote
Quote
I designed my speakers cabinets with a 1 inch thick steel plate (~40 lbs) to go between the top cabinet (containing the midrange and tweeter) and the woofer cabinet.

That is a killer cabinet.  It looks almost as good as Jim's!

Bob

Thanks Bob.  I haven't seen Jim's cabinets in person but from the pictures and the rave reviews, I believe that Jim's cabinets are a notch above mine.   I'm not the most patient person so I went with automotive primer, paint and clear coat since you can put many coats on in a day.  Jim hand rubs his finishes out with curing time between.  The pictures of Jim's speakers look stunning and I understand that the pictures don't do them justice.

Cheers,
Tom

Where did you get the steel plates?  I've been thinking about this or just getting thick marble or granite plates cut and doing the same thing with my speakers.  I know where to get the granite but not steel.  That's a good idea!



Thanks Tom, I'll do a search for steel plates.  If you find the name of the vendor, I'd appreciate a head's up.  Thanks again!


avahifi

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Re: Sensitivity Ratings
« Reply #95 on: 7 Feb 2009, 01:24 am »
Dennis, I am curious as to the results you had with resistive damping of one of those Songtowers.

Regards,

Frank Van Alstine

DMurphy

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Re: Sensitivity Ratings
« Reply #96 on: 7 Feb 2009, 02:47 am »
Well, if I get my taxes done, and if the refund is sufficient to stave off serious depression, I'll perform the experiment this weekend. 

iFi Tyler

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Re: Sensitivity Ratings
« Reply #97 on: 9 Feb 2009, 03:15 pm »
Anyone have anymore to add on this subject?  I find where this thread is going as interesting.

KS

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Re: Sensitivity Ratings
« Reply #98 on: 9 Feb 2009, 03:48 pm »
Where did you get the steel plates?  I've been thinking about this or just getting thick marble or granite plates cut and doing the same thing with my speakers.  I know where to get the granite but not steel.  That's a good idea!
A small local steel fabricating or welding shop will probably do the job very reasonably.  Make a stiff paper or cardboard pattern for them to know exactly what you want if the shape is anything other than a rectangle.  Steel weighs 0.29 pounds per cubic inch--figure out ahead of time the surface area, thickness, and therefore weight you want.  Ask about ways they can cut the edges to make them as smooth as possible.  Plasma cutting is probably good.  You could have the edges machined very smooth at extra cost, maybe taking them to a small local machine shop, if that's you're desire.

Nuance

Re: Sensitivity Ratings
« Reply #99 on: 10 Feb 2009, 11:26 pm »
I've decided to leave my Salk speakers unmodded.  They are just too gorgeous to touch; not joking.  If I really feel I need to have this mod done, I'll send them back to Jim and pay him to do it.  It would give me peace of mind at the very least.  Until then I am off to listen to them "stock," and still loving every second of them!