port help

[highfigh]

...but the sealed will have greater output at 20kHz.

Huh? 20K?

 

[TLS Guy]

Huh? 20K?

Sorry, it was late. Obviously 20 Hz.

 

[ramiro77]

Sorry, it was late. Obviously 20 Hz.

In a vented box, they have an f3 of about 45Hz. But in a sealed box, the F3 is 80hz. Also worth mentioning that in a sealed box, the F10 is 45hz. Ie, achieves the same bass that F3 vented box, but below 7dB. Really do not see how they could make good bass in a sealed... Perhaps I missing something...

 

[TLS Guy]

In a vented box, they have an f3 of about 45Hz. But in a sealed box, the F3 is 80hz. Also worth mentioning that in a sealed box, the F10 is 45hz. Ie, achieves the same bass that F3 vented box, but below 7dB. Really do not see how they could make good bass in a sealed... Perhaps I missing something...

From the point where the lines cross, the sealed rolls off second order 12 db per octave, but the vented rolls off fourth order, 24 db per octave. So yes, the sealed version has more low bass but a higher F3, but the slopes are different.

 

[ramiro77]

Thanks for the info! I will try to then use them in a sealed box. I'll build an enclosure of about 10 or 11 liters, so that once I place the reinforcements, stay with a volume of 8 liters, which is required for the 875 in sealed. On the other hand, what kind of padding do you recommend for a sealed box?

 

[TLS Guy]

Thanks for the info! I will try to then use them in a sealed box. I'll build an enclosure of about 10 or 11 liters, so that once I place the reinforcements, stay with a volume of 8 liters, which is required for the 875 in sealed. On the other hand, what kind of padding do you recommend for a sealed box?

Ideally mineral wool behind the driver. Then the cavity should be completely filled with Polyfill, or equivalent. There should be no compression of the fill, but it must fill the space.

 

[ramiro77]

Excellent. I can get both wool and polyfill where I am. I'll try your suggestions. Although I must admit I'm a bit hesitant about the amount of bass they can deliver in a sealed box. But trying nothing is lost . Thank you very much again for your help!