Screech
Assisted full-range speaker (FAST)


SYNOPSIS

Design:
- Assisted full-range
- Cross at 200-300Hz

Goals:
- Look cool
- Sound good
- Affordable
- Not HUGE
- Simple: Single amp, passive XO


What I want to get out of this project:
- Get back into building stuff
- Start designing filters using Arta
- Have fun building, learning and listening

 


LOG

16-09-2017

Yeah, so... My first DIY project since forever. Needing to start over and rebuild my system I have made a goal to build some stuff just for the fun aspect. "It looks cool" trumps "This is the best sounding" as the initial criteria, not that I would mind if it sounds good. So along those lines I just really liked how some really cheap speakers looked and wanted to make a speaker out of it.

At first I ran into the Dayton Audio PS95 while looking for some speaker parts for my upcoming wood horn project, and at 25 each I just could not resist. A small 3.5" not-really-fullrange-but-close-enough driver, with my first thought being I would stick it on top of my bass cabinet, cross it at 300Hz and have my system up an running. So I quickly made a pair of 6 liter (yes, tiny) cabinets and hooked them up. Oh joy!   Wait, whut.... why doesn't it go louder? Euhm... let's check the specs, this can't be right, 85dB? I guess I have been spoiled in the past, as full-range has always been synonymous with high efficiency. Guess not!  My bass cabinets are around 100dB and would need to be bi-amped or L-padded into oblivion. Okay, so this will not be a placeholder for my main system, so let's make a fun dedicated speaker out of it anyway.

Looking around I let my eye fall on the HiVi Research M8A, an 8" inverted dome woofer with "titanium/aluminium" cone (yeah, I guess they vaporized a few microns of Ti on there somewhere, at 80 I don't think I will get a lot of Ti). Nice size, looks cool and WinISD says it will give me 30Hz in a 70 liter BR cabinet:  Hey, I'm sold.

So far I'm 210 down for a stereo set of PS95 and M8A speakers, add 30 of MDF plus some terminals and we're pretty much set to start building. To keep the speaker flexible in terms of changing out the PS95 later, and just looking cooler than the standard rectangular coffin, the speaker will have a rectangular coffin for the bass and a smaller cabinet glued on top for the "full range" unit. I'll add some pictures later so you will see what I am mumbling about. The bass section will be 68-70 liters, and the FR will have around 6 liters with the ability to shrink that down to 3 liters with an internal panel.

 

22-09-2017

Started building the bass cabinets and gathering all the needed tools, setting up the router and sawing table. Still have all my fingers, yay!   I went full retard and cut all the edges to 45, what could go wrong! Yeah... well... the angle is pretty much dead on, but all the long sides are slight trapezoids. When I put toghether all the panels it will make a nice box, but two sides will not have the tops lined up (slight angle leaving 4-5mm sticking out on one side) . Thank god for power tools.

 

30-09-2017

One cabinet is done to the point where it is closed and ready to be tested. Will finish the other one tomorrow; need to glue in the top and bottom plates and run a router over all the edges to give a slight rounded finish (looks pretty cool). I've ordered some parts to measure the speakers using Arta, which will allow me to start work on the filters (Z correction and XO) for both units. I still need to make the small FR cabinets, but will start testing using the first set of small cabinets I made earlier as they are the same volume (6L) and I will probably see what volume works out the best and make a new section for the speakers instead of making a "variable" volume setup.

 


 
 

Dayton PS95 for 300Hz and up

 


HiVi/Swan M8A for the low end

 


Jim de Kort