Early 2015. 10″ tapped horn “subs” to go with my 2×6″ “top” cabinet, for bass guitar. Also used as bass speakers for house parties at the time. Currently gathering dust, not sure what I will do with these.
These are copies of THAM10 as designed by Anders Martinsson, except with Mivoc AWM104 drivers instead of B&C 10NW64. I don’t remember modifying anything besides the drivers. I went with these drivers because I think they were about a third the price, they have 9mm xmax and they were available in 4 ohm. They model okay down to 60Hz in a THAM10 enclosure – a little more peaky in the bass, but also less efficient outside of the horn response so less noise there and therefore a little easier to cross over. Hornresp modelled response and max SPL at Pmax&xmax with AWM104 (black) vs original 10NW64 design (grey):
They actually sound pretty good for bass guitar with just a THAM10 and the 2×6″ top cabinet, without any crossover. Weight is about 16kg each (10kg wood, 6kg driver). I powered them using a Behringer iNuke NU1000. Iirc, one of the cabs rattles a bit at full volume.
January 2015, text/instructions from back then too. I’m a little sad that I mounted the tweeter up top, and not in the middle as a “nose” with little teeth as drawn as an option in the cutsheet picture. Still, I love how it sounds for bass guitar. Still a great practice amp, only thing I changed since 2015 is put little wheels under it. Might one day make it active by putting a plate amp in the back.
For this 2×6″ top cab, I was mainly inspired by Arjank’s Piccolo8 horn reflex cab, since I really liked the clarity of bass lines on my small horn reflex bookshelf speakers. I was also inspired by greenboy’s cabs that have 6″ mids and a tweeter as a vital part of the sound. I was also inspired by Bill Fitzmaurice’s XF guitar cabs that mount two speakers in a cross-firing position and with a rear tilted baffle. I designed the cab using Hornresp. When I’d finished it, it was a bit peaky in the 100-300Hz region but after stuffing the driver volume it sounded a lot better.
At practice volume, the 2×6″ goes low enough on its own. Over ~40W, I needs a high pass filter >150Hz to keep from farting out (xmax) and I add one or two of the TH cabs.
— Wood — This design uses 12mm plywood. If you are REALLY careful, you can cut all but the tweeter baffle from a quarter sheet (1220x610x12mm). See the cut sheet in the Sketchup file. The entire driver enclosure is tilted backward 9 degrees compared to the horn port. The two 6″ drivers are crossed inward at 20 degrees each. NOTE: the two baffle pieces, the piece at the top of the baffle and the top part of the cab therefore have a few 9 or 20 degree cut angles that you should not overlook!
— Drivers — This design uses two Fane Sovereign 6-100 6″ drivers. The volume behind the drivers and the length of the horn are based on Hornresp simulations of the frequency response of the cab with these particular drivers in it. Using different drivers will have a very big impact on the frequency response of the cab; you will probably get a big thump around 150Hz and not much response in the frequencies below that. At the bottom of this file, you will find the Hornresp values that I used if you wish to try modelling different drivers. That said, the tweeter (Mivoc XGH 258 ALU) could be replaced by a different model or even omitted. If you go for a different model tweeter, you may need to change the crossover. My cab benefitted a lot from stuffing the volume behind the drivers with the insides of a pillow. You could also use actual BAF wadding or wool, and/or line the inside with felt. This will help dampen unwanted sound reflections.
— Crossover — The crossover that I used is a simple passive second order crossover around 2550Hz. The woofers have a combined impedance of 16 ohms around this frequency and the tweeter as well. I used a 3.9uF capacitor and a 1.0mH inductor for both the low pass and the high pass sieds. Make sure the capacitor is bipolar and the inductor is of reasonably low resistance. I am new to crossover design though so I’m sure there are better ways to go about it.
— Crossover switch — If you want to be able to switch between running the 6″ drivers full range, or adding the tweeter via the crossover, use a rotary switch. I’ve used a 4P3T rotary switch that in the third switch position adds an 8 ohm resistor in series with the tweeter. This pads the tweeter a bit, but it also changes the crossover point slightly so this is not the best way to pad the tweeter. I mounted the rotary switch in the horn mouth, where you can easily access it.
— Using the cab — If you use the cab on its own, note that it will fart out if you push more than approx. 40W into it. If you wish to get more output, you can add a high pass filter and cross over the lower frequencies to a different cab. That way, the cab can handle about 200W. I use a tapped horn cab crossed over to the 2×6″ cab around 175Hz. The TH design that I used (THAM10) is freely available on the website of Anders Martinsson, the designer, at http://www.martinsson.cc/
— A suitable amplifier — If you wish to make the cab into a combo, or just want to have a small amp for it, I recommend looking into the TPA3116D2 amplifier. You can order a board cheaply from China (<$20) and its output is perfect for this cab. If you use a 19V laptop power supply, it can push about 35W into the cab at below 0.1% distortion. With a 24V power supply you could get about 60W out of it. If you run in PBTL mode, it is 2 ohm stable and you could get up to 100W if you add another cab. You can set the gain at either 20, 26, 32 or 36 dB. With both pickups at 100% on my jazz bass, I found that the gain was enough to practice without a preamp, but I recommend setting the gain to 32 if you have a passive bass and will not be using a separate preamp. More on this amp at diyAudio here: http://www.diyaudio.com/wiki/TPA3116D2_Boards
— Hornresp input data — Ang 2.0 x Pi Eg 2.00 S1 70.00 S2 280.00 Con 47.00
Sd 139.20 Cms 8.00E-05 Mmd 23.94 Re 6.90 Bl 13.25 Rms 1.35 Le 1.15 Nd 2P
I think I built these in 2014. They’re a copy of the “Leuk & simpel hoorn reflex monitortje met FRS8” project by meiborg on zelfbouwaudio.nl forum. I first wanted to modify it into a triangular shape because of my room at the time, but decided against it because I didn’t have the woodworking tools or skills required.
They use a Visaton FRS8 full range driver, and a horn reflex port to bring the response down to about 100Hz. I like how they sound, I even built someone a second set as a gift.
