custom bottom plate, give me your thoughts.

[SPLaudio 5,000+ posts]

with that much venting in the gap ur loosing ALOT of BL. limit it to 4-6 smaller holes. put in a pole plug and a fairaday ring...

 

[tc3k101 5,000+ posts]

with that much venting in the gap ur loosing ALOT of BL. limit it to 4-6 smaller holes. put in a pole plug and a fairaday ring...

Yep, loss of bl product, you will also raise Qes which will raise Qts or so I read.

 

[kmanian 5,000+ posts]

Yep, loss of bl product, you will also raise Qes which will raise Qts or so I read.

Just learning here, please enlighten me further

 

[T3mpest 10+ year member]

umm if you dont' get basic speaker topology and it's effects you probably shouldn't be building woofers.... BL and Qes are inversely proportional

Qes= (2pi*fs*mms*re)/(BL^2)

If the BL goes up your Qes goe down as your dividing by a bigger number. In real world terms more Bl means at FS your getting a more overly dampened system, at least in the way the parameter is derived. More BL, more control, less oscillation.. QES and QTS are directly proportional. Anyway, if this is something your intested in a few physics classes and some online research starting with what the T/S parameters are good for would be a better use of time than trying to build a backplate.

Anyway you could always use a tight gap to gain back BL, faraday rings are also a good idea. They lower Le as well as minimize it's variation over the stroke of the woofer. This would also allow for a longer coil while still keeping le in check. A longer coil will raise your mms while lowering your fs, which will counterbalance it's effect on qts, at least to a point...

Anyway with a 4" coil I'd defintly want faraday rings. IIRC when TSS was testing the TSNS the biggest issue they had at high power levels was shorting wires due to arcing from stray flux or something to that extent. Faraday rings keep the flux where you want it and this wouldn't occur. I believe the new nightshades use faraday rings and they are mostly an SPL woofer, but it does help scores. It's also good for sq, but really anything that keeps the woofer's t/s parameters linear over it's entire stroke is a good thing for SQ and SPL alike.

 

[SPLaudio 5,000+ posts]

kmanian there is alot of people in the biz here that know there stuff about woofer design such as ^. there is also a few co owners here that are are VERY knowledgeable. asking questions they have always been coo with me...

 

[kmanian 5,000+ posts]

umm if you dont' get basic speaker topology and it's effects you probably shouldn't be building woofers.... BL and Qes are inversely proportional
Qes= (2pi*fs*mms*re)/(BL^2)

If the BL goes up your Qes goe down as your dividing by a bigger number. In real world terms more Bl means at FS your getting a more overly dampened system, at least in the way the parameter is derived. More BL, more control, less oscillation.. QES and QTS are directly proportional. Anyway, if this is something your intested in a few physics classes and some online research starting with what the T/S parameters are good for would be a better use of time than trying to build a backplate.

Anyway you could always use a tight gap to gain back BL, faraday rings are also a good idea. They lower Le as well as minimize it's variation over the stroke of the woofer. This would also allow for a longer coil while still keeping le in check. A longer coil will raise your mms while lowering your fs, which will counterbalance it's effect on qts, at least to a point...

Anyway with a 4" coil I'd defintly want faraday rings. IIRC when TSS was testing the TSNS the biggest issue they had at high power levels was shorting wires due to arcing from stray flux or something to that extent. Faraday rings keep the flux where you want it and this wouldn't occur. I believe the new nightshades use faraday rings and they are mostly an SPL woofer, but it does help scores. It's also good for sq, but really anything that keeps the woofer's t/s parameters linear over it's entire stroke is a good thing for SQ and SPL alike.

kmanian there is alot of people in the biz here that know there stuff about woofer design such as ^. there is also a few co owners here that are are VERY knowledgeable. asking questions they have always been coo with me...

Hey, thanks for taking the time, I completely understand the lack of knowledge on my part, just have never been one to wait, If I decide to do something I jump in, and find the answers as I go. I guess it is the whole ADD thing. I typically am the guy that knows a little about a lot of things, a lot about a little, but I do know how to get people to fill in the blanks and finding the right resources is huge. Hell you just took 2 month of classes and summed it into 100 words. I will say that I am obviously in over my head, and will be searching out individuals that can fill in the very large gaps, and hopefully I can get my origional thoughts through and beat some of the convention. But if not, I will have atleast learned something.

Thanks again