I really wanted to try the new MD60N-6 dome mid from SB Acoustics. I was looking at it for a while and I hoped it will have a discount at some point but no such luck. I then decided to buy it and build a pair of tower speakers. For the low end I chose the MW19P-8 woofer as it had great reviews and the spec sheet is really good. I wanted to do a project with this woofer for may years as well. I had a pretty difficult time choosing the tweeter for this project. The Satori TW29RN-B-8 Ring Dome Tweeter was an obvious option but I read an article about one of the best tweeters around, money no object, (at least that is what the reviewers were saying). It's the Bliesma T25B-6, a beryllium dome tweeter that was around 5-600EUR a pair!!! So really good price for a beryllium tweeter. Unfortunately this was exactly around the time when Bliesma announced that their beryllium diaphragm supplier will no longer be able to supply them with the parts. That meant that the T25B-6 was nowhere in sight. I then decided to go ahead and buy the T25S-6, a silk dome tweeter that was identical in size t the beryllium one and it also had great reviews.
I did a lot of simulations for the crossover filter and I ended up using 600Hz and 3kHz as crossover frequencies. The filter itself is a LR2 topology and it is rather straight forward. This is what the filter was looking like after I simulated it based on datasheet specs:
After I received the drivers and I was able to put the enclosures together, I measured each driver on the final baffle and then I used that frequency response to adjust the filter. I also measured the distance between the acoustical centers of the tweeter and the mid dome using the microphone at 1m distance. As the mid driver is a dome, the acoustical center was only 1mm away from the tweeter's acoustical center and I did not have to spend to much time trying to time align the two drivers.
I proceeded to build a mock-up of the filters and I did many, many measurements. All of these were performed in my living-room as I do not have a dedicated workshop for this. The room itself has acoustic treatment but I still have a room mode at ~200Hz and another one at ~500Hz. So the dips at these frequencies are due to the room modes.
After some tweaking, I ended up with the frequency response seen below:
This is measured at 1m on the tweeter axis. I'm pretty happy with the result. Sound wise, I was surprised to hear how much detail the tweeter and the mid dome were able to send my way. So much so that I had the impression the tweeter was a bit too high level wise. I tried attenuating it a bit more but I did not like it that way. In the end I left it as it was and it will be this way for a few weeks/months. I made the enclosure in such a way that the filter can be easily accessed by setting the speaker on one side. The filters are on the bottom of the enclosure. This means that I will definitely tweak them in the future.
Distortion wise, the measurement looks really nice. I was expecting low distortion from all three drivers and I was not disappointed.
I also used my DATS v3 to measure the impedance of the final speaker and there were no surprises here either.
The enclosures are ported and tuned to ~37Hz. I used three horizontal internal braces. I've put felt on the internal walls and acoustic damping material (the white fluffy stuff).
I'm very happy how these speakers measure and how they sound. I will most probably paint the enclosures black at some point, but for now I'll just listen to them for a while.
For measuring the speakers I used an UMIK-1 microphone and for simulating the filter I used LinearX Crossover Shop and VituixCAD.
I did a lot of simulations for the crossover filter and I ended up using 600Hz and 3kHz as crossover frequencies. The filter itself is a LR2 topology and it is rather straight forward. This is what the filter was looking like after I simulated it based on datasheet specs:
After I received the drivers and I was able to put the enclosures together, I measured each driver on the final baffle and then I used that frequency response to adjust the filter. I also measured the distance between the acoustical centers of the tweeter and the mid dome using the microphone at 1m distance. As the mid driver is a dome, the acoustical center was only 1mm away from the tweeter's acoustical center and I did not have to spend to much time trying to time align the two drivers.
I proceeded to build a mock-up of the filters and I did many, many measurements. All of these were performed in my living-room as I do not have a dedicated workshop for this. The room itself has acoustic treatment but I still have a room mode at ~200Hz and another one at ~500Hz. So the dips at these frequencies are due to the room modes.
After some tweaking, I ended up with the frequency response seen below:
Distortion wise, the measurement looks really nice. I was expecting low distortion from all three drivers and I was not disappointed.
I also used my DATS v3 to measure the impedance of the final speaker and there were no surprises here either.
The enclosures are ported and tuned to ~37Hz. I used three horizontal internal braces. I've put felt on the internal walls and acoustic damping material (the white fluffy stuff).
I'm very happy how these speakers measure and how they sound. I will most probably paint the enclosures black at some point, but for now I'll just listen to them for a while.
For measuring the speakers I used an UMIK-1 microphone and for simulating the filter I used LinearX Crossover Shop and VituixCAD.
. Hopefully I can find a place to rent that I can use as a workshop.
