Back in 2010 i hired Bob Brines to help me with simulation of a MLTL. Many enthusiast in Norway made this construction back then.
This winter (2024-25) I got help from Seas to simulate and measure in the anechoic chamber. IMO their correction filter is very very good.
Here is the driver unit:
https://www.seas.no/index.php?optio...a22rcz&catid=53:prestige-fullrange&Itemid=466
PS! This is only for private use, not commercial!
This winter (2024-25) I got help from Seas to simulate and measure in the anechoic chamber. IMO their correction filter is very very good.
Here is the driver unit:
https://www.seas.no/index.php?optio...a22rcz&catid=53:prestige-fullrange&Itemid=466
PS! This is only for private use, not commercial!
Last edited:
Bob Brines original receipe:
Note that this simulation assumes that the driver output is flat above the low frequency roll-off and the FR22 is not at all flat.
You will have to apply the step filter shown in the applications note to flatten out the top end.
Here are your plans. The drawing and external dimensions are predicated on 18mm material, preferable Baltic birch, but at your option. The top and front baffle are doubled. Alternately you could use 24mm material here. However if you deviate from 18mm material, you will have to adjust the outside dimensions of the cabinet. I have provided the interior dimensions in blue.
I have not drawn in any bracing. At the least, I would suggest window braces on either side of the driver and one or two below the driver. Here: http://brinesacoustics.com/Pages/Articles/Cabinet_Construction/Construction.html in my standard construction procedure. Considering the unsupported depth of the cabinet, you might consider 50x18mm strips glued diagonally across the side panels
I prefer to line my speakers with 15mm high density fiberglass. If need be I stuff them with polyfill. There are many different options, but this is mine.
Note that this simulation assumes that the driver output is flat above the low frequency roll-off and the FR22 is not at all flat.
You will have to apply the step filter shown in the applications note to flatten out the top end.
Here are your plans. The drawing and external dimensions are predicated on 18mm material, preferable Baltic birch, but at your option. The top and front baffle are doubled. Alternately you could use 24mm material here. However if you deviate from 18mm material, you will have to adjust the outside dimensions of the cabinet. I have provided the interior dimensions in blue.
I have not drawn in any bracing. At the least, I would suggest window braces on either side of the driver and one or two below the driver. Here: http://brinesacoustics.com/Pages/Articles/Cabinet_Construction/Construction.html in my standard construction procedure. Considering the unsupported depth of the cabinet, you might consider 50x18mm strips glued diagonally across the side panels
I prefer to line my speakers with 15mm high density fiberglass. If need be I stuff them with polyfill. There are many different options, but this is mine.
Last edited:
2025: enclosures made by a Norwegian furniture carpenter. We made some modifications of the footprint, NOT the vertical dimensions who are necessary to get the right quarterwave effect:
And the «perfect» IMHO correction circuit from Håvard Sollien at Seas:
(Yes, it wasn’t soldered yet 🙂 )
(Yes, it wasn’t soldered yet 🙂 )
The most important here is to go for a low dcr coil. A ordinary resistor and PP cap is enough IMO but with such simple ciricut it is not that expensive to experiment. Have fun 🤩
A kind of but more a loooong bump due to the capacitor shunt after the resistor.
But it is several traditional baffle step filter out there. F ex this I have used since 2010. It sounds also good.
https://www.hifisentralen.no/forumet/threads/seas-fa22rcz-fulltoner-i-mltl.51998/page-4#post-2169565
The beauty with no crossover and only one loudspeaker driver is that the correction filter is easy for newbies to work with 🙂