Help modeling and setting up midbass

[j-roadtatts 1,129]

This topic is to discuss test box alignments and tuning for a 6.5"-7" midbass.  I am planning on testing quite a few mids in different alignments.

MY GOAL IS TO achieve tight accurate dynamic midbass down to 63Hz, with overhead in the output. I am after a very open natural crystal clear sound. I am NOT after punchy colored thick sluggish midbass. 

 My current set up is the Seas U18 in an IB (deadened doors). They are crossed @63hz 24db slope presently. I am running two 15" Icons sealed, crossed @50hz 24db slope. The U in its current alignment handles these frequencys, but  has what I believe to be cone edge resonance once at reference level. Plus has no overhead left for dynamic peaks. They are only on about half power currently... but will be fed full, if not double once dialed. I know this will help with the dynamics, but is not the topic at hand. Also worth noting is I will be adding an H701 DSP before testing, for greater control of the fr.

 I understand a heavy and/or ridged cone and and stiff surround will control cone edge resonance, so a few choices are in that direction. Otherwise these are all picked for large voice coil,  high xmax, and high suspension compliance. Also must play high enough accurately to reach the tweeter.

Mids picked so far:

Evil

Seas U18

Seas CA18

Seas ER

Scan speak 18W 

Dayton rs180

 The test boxes being considered:

IB/deadened door

sealed for a .5 Q

sealed for a .7 Q

ported tuned to 50Hz

ported tuned to 63Hz 

 I understand the effect the ported box has on cone excursion vs output. I understand the trade off of the ported box is either gain efficiency or drop the fs. 

 I see that tuned to 50Hz gives the reach and 63Hz output. 

Here is modeling of the 18W

black 63Hz

red 50Hz

green .762 qtc 

blue .505 qtc

First few questions. Am I approaching this correctly?  How does cabin gain play into this? Should I my model in Leap? Or is it something I can eq out? Am I overlooking anything? 

 Any other input on the topic appreciated and thank you in advance.

[///M5 2,833]

I want to see the bastard ported installed, lol.

The difficulty with what you are doing is that it is midbass focused and not overall output.  There is no replacing your ears.

That being said, a ported enclosure will always win in that department but is not so easy to implement.  Before testing anything I would be sure to really nail down the extreme measures you are willing to take or not and only model what you can/will do.  

As a quick reference the Scan's I volunteered to send you along with the CA's have bucking magnets for HT with old school tv's so they need a larger enclosure to compensate.

[j-roadtatts 1,129]

3 hours ago, ///M5 said:

I want to see the bastard ported installed, lol.

The difficulty with what you are doing is that it is midbass focused and not overall output.  There is no replacing your ears.

That being said, a ported enclosure will always win in that department but is not so easy to implement.  Before testing anything I would be sure to really nail down the extreme measures you are willing to take or not and only model what you can/will do.  

As a quick reference the Scan's I volunteered to send you along with the CA's have bucking magnets for HT with old school tv's so they need a larger enclosure to compensate.

Was in there for contrast... a low performer lol

A .7 cu (20L) enclosure is doable, if it nails down the sound I'm after. Would be a very flat rectangle shape, definitely not a golden ratio. I will be jazzed if I can separate the instruments in that region with the eq on h701 and just roll in the IB door. But must test ported since I'm already there, just to make sure.

I assume port resonance would be the number to keep an eye on when modeling the port? 

The Scan definitely requires the most volume of all drivers modeled, so it either works in the test alignment or it doesn't. 

 

[altoncustomtech 773]

I truly enjoy the ported enclosures I built for the Bravox woofers in the 3 way components I installed in my Traverse. They only need a sub for tracks with lots of emphasis <=45hz. That’s with a .5cuft enclosure tuned to 65hz. 

Youre really gonna love this testing, it’s a blast!!

Just for reference this is how big the .5cuft enclosures ended up.

 

[altoncustomtech 773]

After the epic midbass build its probably tough to find anything that can scratch that itch quite the same way, lol. 

[Tirefryr 1,742]

What's the matter?  Ten inchers scare you now?

[j-roadtatts 1,129]

Would love to master a 7" and tweeter setup one time. Off the record, I will probably do a 3-way with a 10" next. Lol

first system ever was a set of pioneer towers in the back seat on stock hu power. That thing wailed and was crystal clear. So my goal has always been work my way up to that... only built in, with better staging. After this round I will have the knowledge and confidence to pull it off.