1st time trying a series tuned 6th

[shredder2 40]

I've done plenty of ported, a fair amount of 4th's and some parallel 6th adjustments/re-tunes, but this will be my 1st attempt at a series tuned 6th. I really need all the help I can get as I really don't want to waste all my time doing this... and I hate to waste material. I got material sitting in the garage, and since I'm changing setups like socks it seems lately I might as well try one of these next.

I'm curious since the in^ft3 on the lower tuned chamber is fairly high if anyone sees any issues? I went with that much port trying to keep the ratio lower, velocities lower... etc

The higher tuned chamber I went with a bit extra port to keep velocities really low and kept it away from the inner port and driver, is that enough area in anyone's opinion? 

The Sa-15v3d4 will be at 2 ohm nominal on a 1 ohm stable 3K amp (2125 watts rated) so rise and stock electrical (for now) will keep the power down... I'm figuring a bit over 1000 watts best case.

Anyone see any other concerns?.. tuning issues?.. anything at all?

Tyvm for any help or criticism in advance

 

Edited January 29 by shredder2

[Triticum Agricolam 2334]

What are the length of your ports?  If you give me that info I can put it in HornResp and see how it looks. 

[shredder2 40]

Around 39" on the 33hz 3.5ft3 net tuned chamber and 12" for the 58hz 4ft3 net side. 

Edited January 29 by shredder2

[shredder2 40]

46 minutes ago, Triticum Agricolam said:

What are the length of your ports?  If you give me that info I can put it in HornResp and see how it looks. 

Tyvm for the help. The lengths are above ^^^^... any obvious other concerns? 

[Triticum Agricolam 2334]

17 hours ago, shredder2 said:

Tyvm for the help. The lengths are above ^^^^... any obvious other concerns? 

So the thing with series-tuned 6th order boxes is the regular tuning formulas that are used for ported boxes don't work right.  The tunings of the two chambers interact with each other and it will make your rear chamber tuned lower than intended and the front chamber tuned higher.  In your case this is resulting in your rear chamber being tuned to about 35 Hz and the front chamber is tuned to around 60 Hz.  Its not the end of the world though and I think you could build the box exactly how you have it and it will be fine.  Your simulated frequency response in HornResp looks really good.  

[shredder2 40]

1 hour ago, Triticum Agricolam said:

So the thing with series-tuned 6th order boxes is the regular tuning formulas that are used for ported boxes don't work right.  The tunings of the two chambers interact with each other and it will make your rear chamber tuned lower than intended and the front chamber tuned higher.  In your case this is resulting in your rear chamber being tuned to about 35 Hz and the front chamber is tuned to around 60 Hz.  Its not the end of the world though and I think you could build the box exactly how you have it and it will be fine.  Your simulated frequency response in HornResp looks really good.  

I know Winisd is not exactly the perfect tool for this design but I thought (and hoped) I was close.

Once again... thank you for taking the time to model it in Hornsrep, I tried that program on multiple occasions over the years and it still is so far over my head I can't see the bottom.

If you say it looks ok, great... the lowering and small raising of the tune is exactly (ha-ha) what my models indicated.

Any other glaring concerns that should be addressed?

I'll cut some material now... pics or it didn't happen I know

Thank you

[Triticum Agricolam 2334]

2 hours ago, shredder2 said:

I know Winisd is not exactly the perfect tool for this design but I thought (and hoped) I was close.

Once again... thank you for taking the time to model it in Hornsrep, I tried that program on multiple occasions over the years and it still is so far over my head I can't see the bottom.

If you say it looks ok, great... the lowering and small raising of the tune is exactly (ha-ha) what my models indicated.

Any other glaring concerns that should be addressed?

I'll cut some material now... pics or it didn't happen I know

Thank you

I don't see anything that sticks out as being wrong with what you have planned.  Build it and let us know how it works out!

[shredder2 40]

On 1/29/2019 at 10:18 PM, Triticum Agricolam said:

Build it and let us know how it works out!

Not done yet but comin' along. This thing is HEAVY for a single 15... as often as I seem to change setups it would be insane to buy Birch... so once again Mdf is what I used.

Jeez... look at it next to 5.77ft3 net with 108in2 of port... it's a big enclosure for sure 13ft3 externally

Like I said... getting close but considering methods to attach the top panel as one piece and make it removable without tearing the top panel up... All bottom parts are fastened with brads and glue but the top will be screws  obviously if it's removable. I've got a few Ideas but does anyone possibly know a quick and painless method?

Still got a couple of 45's left in the lower chamber and port bend and I think I'll add some small bracing in the port along both sides to stiffen up those large panels but It's looking pretty good Imo... hope it sounds great too .

Once again, thank you for checking the response in Hornsrep... I can't hardly wait to hear this thing. It is my 1st attempt at a series 6th so I was unsure the tendencies I was seeing when modeling would actually occur.

[k58.cross 31]

I know nothing about 6th orders, but this looks really interesting! Don't think I could fit a 6th in my compact car though lol.

[shredder2 40]

Done... serious pita building this thing

146 lb with driver... I'm reserving a hospital room now for when I throw out my back... 

I made the top removable so I can access the sub, possibly add windows on top, and add interior paint later... maybe some lighting inside too?

But for now I'm focused on hearing the thing. I'll finish out and paint it later

pics came out wierd... wow

Edited February 1 by shredder2