First, a little history... About 20 years ago I purchased a set of Def Tech speakers (BP-6B front, BP1.2x surrounds, ProCinema C2 center, ProSub 1000). I have really enjoyed these speakers which I powered with Pioneer Elite receivers (several models over the years). However, I recently switched to a Marantz SR7015 which gave me a couple more channel possibilities to create an Atmos setup. What I really wanted to do was to had some height speakers to the tops of my BP6s, but the speakers were so old that Def Tech doesn't make an add on module for them and I was unable to find a commercial speaker that I liked that would fit on the top since they have a rather small footprint.
So, I had and idea... I am pretty handy in the workshop so I knew building a speaker box would be a no brainer, but I wondered if anyone made a speaker kit with electronics. After a two second internet search I found the DIY speaker community and fell down the rabbit hole! I started looking for a kit I could modify and I eventually settled on the Continuum II by Jeff Bagby. I knew that the box I would need to build would be smaller than Jeff's box, but looking at the specs of the AC130-F1 included in the kit, I figured it would work with a little loss of bass response. This didn't bother me since the intended use was an Atmos height module and frequencies lower than 100hz would not be ideal anyway. So, I decided to jump in and bought the kit. Here goes...
I used MDF for the construction of the box. I have a love/hate relationship with that stuff. Shapes well, but makes a huge mess. The box needed to match the dimensions of the top of the BP6 speakers which was 7x11 inches. I didn't want it to be too tall, but the Dolby patent suggests that they should be above listening height but not higher then half the height of the room. Go figure. Anyway I settled around 10 inches high. In hindsight I probably should have gone one more inch to add some more volume to the box, but oh well. The Dolby patent also suggests an incline angle of 20 degrees, but I saw on several forums that people would get better results when they increased the angle of their Atmos enabled speakers, so I chose 22.5 degrees. This also seemed to fit better with the geometry of my room. Plus the extra couple of degrees would also help if I changed my mind and mounted these on the wall.
Since I wanted these to be a sealed box (just like the Continuum) I decided to add a bit of a rabbet/rebate to help with sealing the corners. I also cut the top angle at 15 degrees to help encourage the signal to shoot up toward the ceiling instead of going forward. And, yes, the tweeter is mounted in front. This will also help if I change my mind and make this a wall height speaker putting the woofer closer to the ceiling.
Did I mention that I have a love/hate relationship with MDF? Well, I coated the whole thing with epoxy resin (alcohol thinned) to seal the whole thing before painting. This will also help hold the screws better when mounting the drivers. After some primer and some gloss piano black it should match the BP6s quite well.
Since this was such a small box the only option I had was to mount the crossover on the bottom baffle under the tweeter. I got a kick out of testing the speakers. It's always a thrill when a project comes together. For those who have gotten to this point and are curious, that is a picture of my daughter throwing the world's worst tantrum at her grandmother's house in her nice Sunday dress. It was so over the top I just had to snap a picture. She is 27 years old now and is still embarrassed.
And here is the final product! It attaches to the top of the BP6s like it was made for it. Oh, wait... It was! I ran the speakers as my main front channels for a day or two and when coupled with my ProSub 1000 they sound wonderful! I can only imagine what they would sound like in a proper sized box. They are a little harder to drive than my BP6 but I was expecting that since they are in a small box and the sensitivity of the drivers is a bit lower. I calculated that they would probably drop off around 95hz or so, and sure enough the Audyssey room correction software set their crossover at 100 and boosted their level 5db
All in all I was happy with my first build. I learned so much about box construction, crossover design, driver specs, etc. And I have so much more to learn.
Thanks for listening! Until next time...
Jason
So, I had and idea... I am pretty handy in the workshop so I knew building a speaker box would be a no brainer, but I wondered if anyone made a speaker kit with electronics. After a two second internet search I found the DIY speaker community and fell down the rabbit hole! I started looking for a kit I could modify and I eventually settled on the Continuum II by Jeff Bagby. I knew that the box I would need to build would be smaller than Jeff's box, but looking at the specs of the AC130-F1 included in the kit, I figured it would work with a little loss of bass response. This didn't bother me since the intended use was an Atmos height module and frequencies lower than 100hz would not be ideal anyway. So, I decided to jump in and bought the kit. Here goes...
I used MDF for the construction of the box. I have a love/hate relationship with that stuff. Shapes well, but makes a huge mess. The box needed to match the dimensions of the top of the BP6 speakers which was 7x11 inches. I didn't want it to be too tall, but the Dolby patent suggests that they should be above listening height but not higher then half the height of the room. Go figure. Anyway I settled around 10 inches high. In hindsight I probably should have gone one more inch to add some more volume to the box, but oh well. The Dolby patent also suggests an incline angle of 20 degrees, but I saw on several forums that people would get better results when they increased the angle of their Atmos enabled speakers, so I chose 22.5 degrees. This also seemed to fit better with the geometry of my room. Plus the extra couple of degrees would also help if I changed my mind and mounted these on the wall.
Since I wanted these to be a sealed box (just like the Continuum) I decided to add a bit of a rabbet/rebate to help with sealing the corners. I also cut the top angle at 15 degrees to help encourage the signal to shoot up toward the ceiling instead of going forward. And, yes, the tweeter is mounted in front. This will also help if I change my mind and make this a wall height speaker putting the woofer closer to the ceiling.
Did I mention that I have a love/hate relationship with MDF? Well, I coated the whole thing with epoxy resin (alcohol thinned) to seal the whole thing before painting. This will also help hold the screws better when mounting the drivers. After some primer and some gloss piano black it should match the BP6s quite well.
Since this was such a small box the only option I had was to mount the crossover on the bottom baffle under the tweeter. I got a kick out of testing the speakers. It's always a thrill when a project comes together. For those who have gotten to this point and are curious, that is a picture of my daughter throwing the world's worst tantrum at her grandmother's house in her nice Sunday dress. It was so over the top I just had to snap a picture. She is 27 years old now and is still embarrassed.
And here is the final product! It attaches to the top of the BP6s like it was made for it. Oh, wait... It was! I ran the speakers as my main front channels for a day or two and when coupled with my ProSub 1000 they sound wonderful! I can only imagine what they would sound like in a proper sized box. They are a little harder to drive than my BP6 but I was expecting that since they are in a small box and the sensitivity of the drivers is a bit lower. I calculated that they would probably drop off around 95hz or so, and sure enough the Audyssey room correction software set their crossover at 100 and boosted their level 5db
All in all I was happy with my first build. I learned so much about box construction, crossover design, driver specs, etc. And I have so much more to learn.
Thanks for listening! Until next time...
Jason