Underhung TC Nomz

[Ray21 10+ year member]

Underhung typically has a thicker top plate.

 

[psychoacoustics 10+ year member]

mmmm

 

[ciaonzo 5,000+ posts]

So based on this, underhung/overhung has nothing to do with the actual motor, but only the coil? I hear people all the time saying underhung motor. Not saying it's correct, but I was led to believe it was almost solely based on the motor as well.

It's a relationship between the two. Underhung describes a situation where the coil is decidedly shorter than the top plate. You can take a motor with a thick top plate and put a coil with a short wind width in it and it will behave in a very linear fashion. That is, stroke will increase in proportion to decreasing frequency (without enclosure influence). Take that same motor and stick a much longer coil in it and it will not only be considered overhung again, it will likely have a very high BL product. It's also very likely to have a very peaky parabolic BL curve due the number of windings in the gap decreasing almost as soon as the coil moves in either direction and will not behave as linearly as the short coil did in that same gap, or even a conventional overhung configuration with a long coil and short gap relationship.

 

[ciaonzo 5,000+ posts]

This overhung driver has a tall top plate but it also has a long coil. It's designed to have a high BL product rather than the linearity of a short top plate with that same coil.

 

[gckless 5,000+ posts]

It's a relationship between the two. Underhung describes a situation where the coil is decidedly shorter than the top plate. You can take a motor with a thick top plate and put a coil with a short wind width in it and it will behave in a very linear fashion. That is, stroke will increase in proportion to decreasing frequency (without enclosure influence). Take that same motor and stick a much longer coil in it and it will not only be considered overhung again, it will likely have a very high BL product. It's also very likely to have a very peaky parabolic BL curve due the number of windings in the gap decreasing almost as soon as the coil moves in either direction and will not behave as linearly as the short coil did in that same gap, or even a conventional overhung configuration with a long coil and short gap relationship.

This overhung driver has a tall top plate but it also has a long coil. It's designed to have a high BL product rather than the linearity of a short top plate with that same coil.

Ok, I think I got it. So, to put it basically, linearity is derived from the amount, or maybe consistency is a better word, of the coil being in the gap? As as soon as the gap sees free space (the top coil extending downward past the top of the gap, or the bottom of the coil extending upward past the bottom of the gap, where there is still coil to the other side of the gap and possibly past it) linearity will decrease? Maybe I explained that weird, but I think I have it laid out in my head.

And based on that, that means either a very long or very short coil, depending on motor and top plate, can be equally as linear, correct?

 

[ciaonzo 5,000+ posts]

Ok, I think I got it. So, to put it basically, linearity is derived from the amount, or maybe consistency is a better word, of the coil being in the gap? As as soon as the gap sees free space (the top coil extending downward past the top of the gap, or the bottom of the coil extending upward past the bottom of the gap, where there is still coil to the other side of the gap and possibly past it) linearity will decrease? Maybe I explained that weird, but I think I have it laid out in my head.
And based on that, that means either a very long or very short coil, depending on motor and top plate, can be equally as linear, correct?

Yep, I think you've got it.
To answer your second question, that's pretty much correct as long as we're strictly speaking about the motor (equals coil/magnet assembly). Soft parts will also influence the linearity depending on the intended purpose of the driver but that's a bit outside the scope of this conversation.

 

[gckless 5,000+ posts]

Yep, I think you've got it.
To answer your second question, that's pretty much correct as long as we're strictly speaking about the motor (equals coil/magnet assembly). Soft parts will also influence the linearity depending on the intended purpose of the driver but that's a bit outside the scope of this conversation.

Nice. Appreciate the tutoring bro.

 

[ciaonzo 5,000+ posts]

Nice. Appreciate the tutoring bro.

Aw, no worries. And please do your due diligence to read more scientific articles about motor topologies, I'm doing a lot of generalizing for the sake of easier typing, lol. There are many many aspects to motors. For instance, we haven't even touched on the flux gap width. Another huge game changer!
This article does a small bit of explaining some things that weren't discussed here.

AE Speakers --- Superb Quality, Unforgettable Performance, Definitely.

 

[ciaonzo 5,000+ posts]

Jacob laid down some nice explanations and accompanying graphs depicting BL curves, in this thread.

I need Bl/Bl Curve Explained - General Audio - Cant find a category for your question? Ask here. - SMD Forum

 

[ciaonzo 5,000+ posts]

I'll leave it alone after this - some very technical talk between some of the star designers of the lowest distortion topologies on the planet, LMS and XBL^2.

Any 21’s on the horizon with XBL^X?

 

[sundownz Pro Seller]

I'll leave it alone after this - some very technical talk between some of the star designers of the lowest distortion topologies on the planet, LMS and XBL^2.
Any 21’s on the horizon with XBL^X?

Always a fun time to read Dan's posts //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif Printed out all of them that I could in college.

 

[ciaonzo 5,000+ posts]

Always a fun time to read Dan's posts //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif Printed out all of them that I could in college.

I would say that it payed off in spades, young man. Keep up the good work! //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[neo_styles 10+ year member]

Bringing this thread back to life for a few extra questions (thanks @gckless for reminding me this was here).

I'm planning out a build for when I have my reenlistment bonus handy. Vehicle will be an 00-02 Chevy Tahoe with a Zapco DSP-Z8 for processing. As for amplification on the sub stage, I'm considering either a Zed Minotaur II or Zapco Z-2KD (maaaaybe a 3KD), each of which will put out a clean 1.5k at 2 ohms. The overall goal is what most would consider SQL as in I'm looking for clean, accurate bass with a little oomph for when it's needed.

Now here's where the underhung question comes in hand. I've been bouncing back and forth between a couple underhung subs for this application and have about 6-7 cubes of space to play with (basically where the third row would be in a Tahoe plus a few extra inches into the cargo bay). I understand that you don't get a crud-ton of underhung subs expecting massive output and I'm not in the game to do hair tricks anyway, so consider that removed from my concerns as well. Anyway, here are two choices I've come up with so far:

1. A pair of 12" IA Flatlyne. Like how low Fs is on these and other T/S look impressive (guess I'm glad there's any T/S considering how hush hush IA is about their sub specs)
2. Have Murph from Tantric build me a HDD, but with an underhung coil. This brings power handling down to about 1K which would make it easier to drive on my amp choices.

Seeing as how I'm relatively new to the world of underhung subs, I'm just trying to get a feel for what sonic characteristics I should expect from most Daily Driver sub setups. In the past, I've run W3, W6, Infinity Ref/Kappa, ID10, and am currently on a DC Audio Level 2 10" in a slightly oversized box (makes it a smidge boomy, but I can handle it). I proposed this elsewhere, but am looking for a few guys' opinions on what to run without breaking the bank. Including the purchase of the Tahoe, I'm looking to spend no more than 10K.

As for music, I listed to just about everything, so want this sub stage to feel at home playing anything from Miles Davis to Mozart to Martin Solveig to Megadeth and everything in between.
@ciaonzo ; @sundownz ; @hispls ; @denim ; and @TaylorFade ; @SPLaudio ; looking for your opinions in particular.

 

[Slo_Ride 5,000+ posts]

tempest

 

[neo_styles 10+ year member]

tempest

Elaborate please?

*edit* never mind. Forgot about Adire. Just not sure how easy it's going to be to find one of those let alone a pair.