Zaph 5" nearfield

[Rick Craig]

Any nearfield tests available (up to 200hz) for the Zaph 5" in a sealed cabinet?

[jkrutke]

Hi Rick,

Well, digging through my measurements, I've got a high level nearfield response and impedance curve in a 4.43 liter box, which is what I used for the delta compliance Vas measurement, along with confirming my T/S numbers. I never posted that but I can if you'd like to see. It's only accurate up to maybe 600 Hz though.

[Rick Craig]

Hi Rick,

Well, digging through my measurements, I've got a high level nearfield response and impedance curve in a 4.43 liter box, which is what I used for the delta compliance Vas measurement, along with confirming my T/S numbers. I never posted that but I can if you'd like to see. It's only accurate up to maybe 600 Hz though.

Thanks - if you can post it that would be great. I have someone interested in a sealed design but I wasn't sure if the -3db point would meet their goal for the monitor.

[jkrutke]

Here's a near field (1/4" mic distance) with the mic about 1.5" in from the cone edge in a 4.43 liter box, a close up of the impedance in that box, and then a modeled curve in that box based on the measured T/S parameters.

F3 in sealed is around 100 Hz almost regardless of the box it's in. Not deep enough to use without a sub, IMHO.

[Rick Craig]

Here's a near field (1/4" mic distance) with the mic about 1.5" in from the cone edge in a 4.43 liter box, a close up of the impedance in that box, and then a modeled curve in that box based on the measured T/S parameters.

F3 in sealed is around 100 Hz almost regardless of the box it's in. Not deep enough to use without a sub, IMHO.

Thanks!

[polacchini]

Hi all,

I'm also interested in a ZA5.2 for nearfield listening, but in the ported config. I'm following Zaph's advice regarding enclosure size (mine's gonna be 7L), tuning (about 62Hz with the stock port) and reduced BSC crossover.
The only detail I'm not sure yet about is where to mount the port, on the front or back. Using the 7L cabinet drawing, I won't have enough baffle height to place the port there, so I'll probably go with the rear mounted port, or a rectangular custom port.
So... I know there are some trade offs, but they aren't that clear for me, as this is my first diy speaker building project. If I understood right , I'll lose some bass output around the tuning frequency with the port on the back for nearfield listening, won't I?

Any kind of help is much appreciated!

Cheers

[Mark K]

Hi all,

I'm also interested in a ZA5.2 for nearfield listening, but in the ported config. I'm following Zaph's advice regarding enclosure size (mine's gonna be 7L), tuning (about 62Hz with the stock port) and reduced BSC crossover.
The only detail I'm not sure yet about is where to mount the port, on the front or back. Using the 7L cabinet drawing, I won't have enough baffle height to place the port there, so I'll probably go with the rear mounted port, or a rectangular custom port.
So... I know there are some trade offs, but they aren't that clear for me, as this is my first diy speaker building project. If I understood right , I'll lose some bass output around the tuning frequency with the port on the back for nearfield listening, won't I?

Any kind of help is much appreciated!

Cheers

I think I modeled Zaph's driver in an ML TL using Martin King's software. Not sure what you used for your TL dimensions. Let me know if you're interested in the box dimensions.

mark

[DancesWithBeers]

He also mentioned that the port should be front-mounted for nearfield listening. How close will you be listening?

If there is not enough height for a round port, possibly you could do two smaller ports, or a slotted rectangular port on the bottom?

-DWB

[polacchini]

I think I modeled Zaph's driver in an ML TL using Martin King's software. Not sure what you used for your TL dimensions. Let me know if you're interested in the box dimensions.

mark

I'm using Zaph's 7L sealed dimensions (.25 cu ft, 10,5H x 6,5W x 7,5L internal), with the stock port (1,5in x 4in). I'll probably won't try to make changes to ready designs by myself as this is my first project, but any help from you experienced folks are more than welcome

He also mentioned that the port should be front-mounted for nearfield listening. How close will you be listening?

If there is not enough height for a round port, possibly you could do two smaller ports, or a slotted rectangular port on the bottom?

-DWB

That's gonna be about 3 feet (1m). I'm considering a slotted port on the bottom, but I'm not sure how to calculate it's length. The lenght I have thus far is a 23cm (9 in L x 6,5W x 0,75H) port, using a free web-based calculator. I've tried to input the K=2.23 (slotted port end correction ) on both WinISD and Unibox, but that didn't give me a reliable answer. When I have enough spare time, I'll try fiddling with the equations myself to get a definite answer for this.

Thank you all very much