From the performance point of view, a 3 way should be better and I should definitely try that one day. I tend to like the "kick" from a separate midbass horn. I wonder if I can get that from a 3 way MEH as well - in some reasonable size and weight.
A very small update - with 3D printed back covers on the Faitals, the low crossover can be around 200 Hz on the low end, which is a good enough result for me. I actually forgot to save the measurements, but it seems that the back covers are extending the low end a bit. I had to pad down the DE500 some 5 dB and a bit of EQ to straighten the upper end FR, but for the first test, it sounds really good. I will have to optimize the EQ and crossover a bit. The next in line for a test is the AMT Synergy with only two 3FE22s, which will be set up as the other speaker for stereo.
So here are some measurements, again with a quick crossover at 930 Hz (LR4) and some PEQ using REW to calculate the filters. The second plot is with a paraflex kickbin, the dip at 140 Hz is from the room. I did not have spare time to listen, still need to set up the left side with the AMT Synergy. I am quite happy with the results so far.
I have also noticed this in simulation that the low end can be brought up a bit by the rear chamber been correctly sized. Results look good! I'm listening to to a very simlar speaker right now (3" driver unity horn). I cross from my unity horn at 500Hz to a 15" midbass and don't notice any localisation issues all the sound appears to come from the horn until very close to the speaker.
Second side is set up. As expected, the AMT horn is less efficient, around 2 - 3 dB. I still need to work on the crossovers and delays. Each sounds slightly differently, but mono recordings are perfectly in the middle. Still happy, bit also lots of work (and fun) ahead🙂
Attachments
Beyma 15 CM V2: https://www.beyma.com/speakers/Fich...akers-data-sheet-low-mid-frequency-15CMV2.pdf . Its a fine driver but mainly I'm using it as it was exceptionaly cheap (£36).
Well, I must say that the MEH is really something special.The DE500 is really lacking compared to the Heil AMT, but both the Runt-clone and AMT single flare horns have the "magic" sound to them. I will now begin slowly working on the largest MEH that I can build on my CNC (ca 80 x 80 cm workspace), single flare, Syn9 style. I bought today the very fine Beyma CP755Nd drivers, which will be the base for this.
I think this prototype has served its purpose. It will be soon dismantled and put to storage - as well as the second prototype based on AMT. But not before some more measurements, the weather is slowly getting better and one of the following weekends will be used for a large measurement session.
Hello, just curious if you plan on releasing any plans for your runt clone? I’m very interested in building my own
If you want, I can send you the F3D file and the components as STL objects. I do not have any other drawings. Be warned, the F360 file is pretty chaotic. PM me your email and I will send a zip via WeTransfer. It is just the horn, you would have to make your own box around it.
By the way, the large synergy horn is on hold due to other projects at the moment, I am not yet decided which unit to use for bass.
@Johannes619 No, you cannot until you have cleared the moderation approval process. However you may request, receive and reply to them.https://www.diyaudio.com/community/threads/new-members-can-not-send-private-messages.384831/latest
I decided to revisit this horn. Johannes619 had some great results with Fane Sovereign 8-225 and I have an unused pair of DAS M50 drivers at home. I can imagine these with bass reflex for home level listening - mounted on TV wall holders to be able to bring them further into the room. Time to cut some wood again🙂
I wonder if extending the secondary flare would be beneficial - at least for some more patern control. I wonder if it would be better to redesign to a single flare in the same external dimensions amd have the secondary flare removable - sort of Mini-SynTripP - decisions, decisions...