Dedicated Thread for Subwoofer Knowldge -

[osix 10+ year member]

Adhesive

SOmething that had been overlook and unseen . alot of maker , would save cost on this . as alot of average adhesive would give the same during daily operation .

is the extra mile that you encounter problem . a common problem is the adhesive breaking down due to Heat . or after long hour of operation -

many term had been use to show off the kinda special adhesive

eg. Aero Space Glue , Dynamic bonding , super grade ,.

BUT some can be misleading . as the trick is to find the right adhesive on the right spot .and of cos choosing the right adhesive for the operation you want .

so SPL sub may need special adhesive which might give you better heat control .

In return there is not BEST sub only one that suit your use.

Good luck and feel free to correct me if i am wrong

 

[osix 10+ year member]

Anyone can touch on Topic on the Type of Magnet and choice and combo used on SUB

Usually Ferrite is used .

STRODIUM , DURIUM , ( there are alot more - )

Magnetic Separator - using the WET or DRY process

There come in alot of measurement .Which can range from 120mm - 220mm in diameter and larger depending on the use .

The thickness also range from 15mm - 30mm and also larger customer size .

Is common that maker use Double or more layer to stack up the magnet ,

In some design . as much as 14-28 smaller magnets is used .One example of multi magnet design would be FOCAL Utopia .

Every maker have their special design . Do keep in mind . Bigger magnet or More Magnet Does not = Better Sub . It really boil down to personal choice . Nowaday alot of Buyer will buy a Sub base on how large the Magnet is or how high the MAX Watt is rated . all this is commercial way to attach new buyer .

Someone once say one man cup of tea can be another man poison .

so while some find their speaker sound really good . another person might not .

so there is not BEST Sub out there . just what you like .

Feel free to correct me and point out my error or i you have any info please Add to this as it would help alot of user in future .

Thanks

 

[jimrhit 10+ year member]

Magnet Choices are usually either Ceramic or Neodymium.

Ceramic comes is a bunch of different grades, rated with a Y## to indicate the magnets quality.

A "bigger" magnet can be two things .. taller .. and wider. A taller magnet does little to add to the B-element of Bl, whereas a widening (diamter increase) add significantly. Manget stacking is usually used for mechanical clearances when it is deemed cheaper than machining/forging steel rebate or bumps.

Multiple magnet can be used to save money (when making an 11" magnet is difficult) or when it is more reliable (thin magnets are prone to cracking, so multiple pie pucks are used)

 

[Papermaker85 5,000+ posts]

where to start? first and foremost IMO the most important part of construction is the GLUES....... i have found quite a few good adhesive and coating companies.... if you really want to understand how a speaker works you need to break it into sections....

cones

surrounds

basket

spiders

former

voice coil

top-plate

permanent magnets

back plate/t-yoke

then maybe each individual topology

materials used for each as well as different designs used with each...

The voice coil must be separated from the former in order to provide the proper resistance.... otherwise it will energize the former itself... this material also affects thermal power handling... some companies use a metal former and coat it with a dielectric coating(of course ceramic)....this is a great way to separate the VC windings from the former and obtaining a high power handling..

spiders are a very important part of the driver as well... the current spiders are usual a cloth material soaked in resin..not much advancement there....

its best to pick a topic so it can be discussed specifically.... i think a good place to start would be the glues themselves...

 

[osix 10+ year member]

Anyone cna ttouch on topic of Xmax ?

 

[almond 10+ year member]

along the lines of xmax, maybe tc sounds could talk about what the lmt tech is and how it works.

 

[jimrhit 10+ year member]

I'm not TC Sounds, but LMS is simply a variable winding width voice coil. It adds more L as excursion increases to maintain a linear BL vs. X curve.

Xmax has typically been said to be the 70% of the static (rest) Bl number. This has been suggested to be changed by Klippel to 82% (the more realistic onset of distortion), but many feel that with bass frequencies, 70% is fine.

 

[squeak9798 5,000+ posts]

along the lines of xmax, maybe tc sounds could talk about what the lmt tech is and how it works.

http://www.soundsolutionsaudio.com/forum/index.php?showtopic=2748

http://forum.carstereos.org/difference-between-xbl-t56398.html