I have built an Tabaq-like MLTL with Dayton PS95-8. The internal box volume is ~9.5 L, current port length 80mm, diameter 36mm. It is simple round port, the speaker box is shelf type and used as a shelf type, so no bass augmentation from the floor is needed/used.
I want to remake the box and due to the specific folding, I cannot use 80mm length port, so I need something shorter, also I cannot use the variable length tubes I like so much. According to http://www.p10hifi.net/FAL/downloads/ChangingPortSize.pdf I recalculated, that if I chose port length ~71mm, its diameter will be 32mm.
The Sd of the PS95 is 28.3cm2, the original port cross section is ~10.2cm2, so a bit more than 1/3, ~35% Sd. The new port cross section is ~8cm2, which is right between 1/3 and 1/4, ~28% Sd of the driver.
Listening levels are smth from "personal" to "movie" but far from"party". With the original 36mm diameter vent I hear no sound artifacts because of port turbulence. It just sounds OK for me. If the sound level is bigger, it feels that the driver is approaching its limits faster than the port.
The question: will the same internal volume (and MLTL line length) box with the new smaller port be OK or the port is simply too small?
Thank you.
I want to remake the box and due to the specific folding, I cannot use 80mm length port, so I need something shorter, also I cannot use the variable length tubes I like so much. According to http://www.p10hifi.net/FAL/downloads/ChangingPortSize.pdf I recalculated, that if I chose port length ~71mm, its diameter will be 32mm.
The Sd of the PS95 is 28.3cm2, the original port cross section is ~10.2cm2, so a bit more than 1/3, ~35% Sd. The new port cross section is ~8cm2, which is right between 1/3 and 1/4, ~28% Sd of the driver.
Listening levels are smth from "personal" to "movie" but far from"party". With the original 36mm diameter vent I hear no sound artifacts because of port turbulence. It just sounds OK for me. If the sound level is bigger, it feels that the driver is approaching its limits faster than the port.
The question: will the same internal volume (and MLTL line length) box with the new smaller port be OK or the port is simply too small?
Thank you.
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Low power drivers generally only need Sd/4 IME, so you're probably fine, but if you can hear some, then 'critically' damp it.
Click test: Click Test | GM210 | Flickr
GM
Click test: Click Test | GM210 | Flickr
GM
Hello,
Neat little program for playing with port area. Your speaker may be a bit small for it, but you may be able to bet a better idea of an appropriate size.
Flare-it - Free Speaker Design Software
Regards,
Greg
Neat little program for playing with port area. Your speaker may be a bit small for it, but you may be able to bet a better idea of an appropriate size.
Flare-it - Free Speaker Design Software
Regards,
Greg
I don't have measuring gear to understand what W from amp at specific SPL I am using at some specific moment... If I knew that - yes, I could compare. In normal listening conditions and with this damping I barely go more than 2W, with the port velocity far less than 10% of speed of sound, but who knows. Also with the current 36mm port the same speaker sounds not boomy at all and the port noises are far lower than many of the speakers I heard.