EV Sentry III Series II speaker cabinets

[jorb]

Hello,

I recently obtained a gutted pair of Series II speaker cabinets.
After measuring the Sentry III Series II cabinets and comparing them to the Sentry III Series I cabinets.
I notice the vents dimensions and the cubic footage between the two cabinets are different. Yet the SI & SII EV spec sheets claim identical acoustical output measurements. When I use this Port Length Calculator it calculates a different port length than what is in the EV Sentry III Series I & EV Sentry III Series II speaker cabinets.
Why Did EV change the ports / vents?
I believe the cabinets were tuned for 40 hz

Series I,
Vent dimensions
Top vent, 7" wide x 4 1/2" high x 10" deep
Lower vent, 7" wide x 6 1/4" high x 10" deep
cabinet volume
7.80 cubic feet

Series II,
Vent dimensions
Top vent, 7 7/8" wide x 4" high x 8 1/4" deep
Lower vent, 7 7/8" wide x 5" high x 8 1/4" deep
cabinet volume
7.03 cubic feet

Thanks,

 

[totem]

Visually the cabinets are slightly different, perhaps the internal dimensions are not actually the same hence making the ports vary between the I and II,s

Just a guess on my part.
I have the Sentry III mk I,s.

 

[jorb]

Visually the cabinets are slightly different, perhaps the internal dimensions are not actually the same hence making the ports vary between the I and II,s

Just a guess on my part.
I have the Sentry III mk I,s.

Do your Sentry III mk I,s match the below ports dimensions?
Port dimensions
Top vent, 7" wide x 4 1/2" high x 10" deep
Lower vent, 7" wide x 6 1/4" high x 10" deep

On the Sentry III mk I,s
The actual routed out 3/4 inch front face of the port openings (the above dimensions) are smaller than the internal port chambers by 1 1/2 inches on the right hand side of the top port and the right hand side of the lower port and by 1 1/2 inches on the bottom of the lower port.

Do your Sentry III mk I,s internal ports match the below ports dimensions?
Top vent, 8 1/2" wide x 4 1/2" high x 10" deep
Lower vent, 8 1/2" wide x 7 3/4" high x 10" deep

The Series II, internal ports dimensions are:

Top vent, 8 3/4" wide x 4" high x 8 1/4" deep
Lower vent, 8 3/4" wide x 5" high x 8 1/4" deep

The Series II lower port does not use the bottom cabinet board as part of the port chamber, The Sentry III mk I does. The bottom of the Series II lower port has it own board and the opening starts 2 3/8" from the top side of the bottom cabinet board.

I am wondering what port dimensions matter the front face port openings or internal port chamber dimensions when determining port length?

Thanks

 

[perchdog]

I doubt tis enough difference to make a huge impact, especially if you do not have the eq.

 

[jorb]

I doubt tis enough difference to make a huge impact, especially if you do not have the eq.

Do you have Sentry III's?
When calculating port size how accurate do you have to be?
I do not have the step down mode EQ but would like to use the cabinets in step down mode some day.

Thanks,

 

[perchdog]

Do you have Sentry III's?
When calculating port size how accurate do you have to be?
I do not have the step down mode EQ but would like to use the cabinets in step down mode some day.

Thanks,

Yes I do...

At first I was dissappointed in the bottom end performance, I went to bi-amp configuration and was able to get them more into the range I like. I have not run the stock cabs / woofs in quite some time, I run with JBL scoop cabinet and GPA 416 woofer currently. The mid-horn, x-over and tweet is very difficult to beat in my book, especially for the price. I will soon install all the bits and pieces back in to the Sentry cabs and run with some JBL 18" cinema subs.

 

[bobrown14]

I run a pair of MKIIs holly grail and I have the SEQ (free off epay with another piece of gear) lower port covered... it's all good. I'm a lucky bast'd ...2 franklins plus NOS woofers for another franklin, recap (really not needed but hey did it anyway) another franklin, off to audio nirvana. If you put these in a decent sized room with tube power and you will be too (nirvana). These speakers got me into audio DIY. Thanks to the Gods.

Call me lucky!

Cheers,
Bob