There's no one answer to that. Leaving personal preference aside, it depends on your amplifier output impedance and / or any series R in the circuit; for instance when the P11 came out I did a handful of boxes including some relatively large ones not dissimilar in size to this, assuming high output Z amps. It also depends on your intended positioning & expectations. I'd probably be inclined, if you're simply lagging the box walls (avoid the usual egg-crate acoustic foam if at all possible) I'd tune to 42Hz & keep them reasonably near a wall. That should give quite a nice, extended LF output once room gain &c. is factored in. However, most straightforward / DIY approach of all is either to use a duct with an adjustable length, or simply tune to the lower frequency & shorten the duct as appropriate if you so wish.
Thanks for the quick response. If the solide state amplifier has high damping factor, is still Fb= 42Hz your reccomendation?
Also do you think a zobel network would be useful?
I'm using 8mm wool felt to cover 40-50% of internal area. I'm planning to test adding some extra foils of polyfill as well..
Ok test ist going on well... 
I tuned with a paper tube at about 42Hz (which was better than 38Hz) cutting away about 7 cm, but i had to extra fill the box with a single foil of 1 inch of polyfill (in addition to the existing wool felt) to get a clean and flat_to_the_ear response. The damping lowered down the Fb to about 39Hz. Probably I will not move from this.
I'm testing also a slight zobel network in parallel which made voices slight more focused and warm (1uF + 8~10 ohm).
Testing and tuning is really time consuming...
I tuned with a paper tube at about 42Hz (which was better than 38Hz) cutting away about 7 cm, but i had to extra fill the box with a single foil of 1 inch of polyfill (in addition to the existing wool felt) to get a clean and flat_to_the_ear response. The damping lowered down the Fb to about 39Hz. Probably I will not move from this.
I'm testing also a slight zobel network in parallel which made voices slight more focused and warm (1uF + 8~10 ohm).
Testing and tuning is really time consuming...
finished!
Hello, just finished the loudspeakers...Tuned at 39Hz with internal stuffing.
Bass is extremely deep and clean, terrific for such a small speaker!
Very extensive response, in the highs too, which are sweet, smooth and gentle, but mid is not forward at all and become poor for speaker off axis response, so you need to turn the speakers in front to you to reproduce voices correctly and live.
Definitively a good low-distortion speakers but cabinet positioning, tube tuning, internal stuffing and selecting the right source is critical and time consuming. Not an easy speaker: you need to spend hours (trial and error) to get the right alignments.
Hello, just finished the loudspeakers...Tuned at 39Hz with internal stuffing.
Bass is extremely deep and clean, terrific for such a small speaker!
Very extensive response, in the highs too, which are sweet, smooth and gentle, but mid is not forward at all and become poor for speaker off axis response, so you need to turn the speakers in front to you to reproduce voices correctly and live.
Definitively a good low-distortion speakers but cabinet positioning, tube tuning, internal stuffing and selecting the right source is critical and time consuming. Not an easy speaker: you need to spend hours (trial and error) to get the right alignments.
Attachments
As I told you, Pluvia 11 are very good, low distortion speakers but very sensitive to box contruction and stuffing (damping). They have excellent and clean bass, but the risk is to have Mids which result too much "veiled".
After weeks of several tempts I found the solution and the mistakes I was doing: don't stuff too much around the box on the sides with polyfill, but stuff in the right position, which is just in the middle of the box where air velocity is max.
Here you can read some interesting readings:
Damping Treatments
and
How to remove internal standing waves from speaker cabinets?
In the pic the two solutions I found for my box, both are working very well, but the first has the best trade-off, thus was what I adopted!.
Now I have excellent deep Bass and excellent clear Mids!
After weeks of several tempts I found the solution and the mistakes I was doing: don't stuff too much around the box on the sides with polyfill, but stuff in the right position, which is just in the middle of the box where air velocity is max.
Here you can read some interesting readings:
Damping Treatments
and
How to remove internal standing waves from speaker cabinets?
In the pic the two solutions I found for my box, both are working very well, but the first has the best trade-off, thus was what I adopted!.
Now I have excellent deep Bass and excellent clear Mids!
Attachments
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.