I found out I am out of M6 threaded inserts🙁 On the other hand, I had success mounting the stand on the horn using a dowel drilling jig for the first time🙂
I have not seen any of that - not that I was looking for it. When this is finished, I will try to look into it. At home listening levels, I heard nothing wrong. Any extra distortion could be masked though.
These are my results with open back and small baffle. The 300 Hz dip most probably comes from that. The difference is not great, but there is some. Especially around 475 Hz, that dip seems like cancellation from different path lengths to the hole. Also, there is more HF noise from the hole in the center. Even though the center hole brings the entry further from the throat, it should be still possible to crossover to the AMT. Hornresp confirms that, so I will use the center hole.
I tried drilling a smaller entry hole (5 cm2) and that is clearly making things worse. Now I need to drill the proper entry hole and tune the DSP. I still hope to avoid using smaller mids in this project.
Now it finally plays fine, with 2x12" bass section from another MEH below it. The entry hole is a bit further than optimal, I think I will just have to use smaller mids to get better integration. Also, the 8PE21, for some reason does not sound as good as in the larger horn before.
It is comparable to the EAW CB152 two way cinema speaker with a 90x90 CD horn and a 15" - I used a little bit of EQ to roughly match the FR and they work fine together as the left and right channels.
I am not very impressed, the AMT is difficult to mount and it seems it is not really suitable for this particular horn. I will pull out the other smaller one I built some time ago and try to set it up for the other channel.
I think I will return to traditional CD based 3 way construction with symmetrical driver placement.
It is comparable to the EAW CB152 two way cinema speaker with a 90x90 CD horn and a 15" - I used a little bit of EQ to roughly match the FR and they work fine together as the left and right channels.
I am not very impressed, the AMT is difficult to mount and it seems it is not really suitable for this particular horn. I will pull out the other smaller one I built some time ago and try to set it up for the other channel.
I think I will return to traditional CD based 3 way construction with symmetrical driver placement.
This is a picture of the test setup, the MEH is delayed a bit - not ideal, but it sort of works.
Now I am listening to some favorite tracks and it is definitely not bad, especially the efficiency is nice, the amp lights barely flash.
The "center channel" is not connected, but the illusion is that it is the only speaker playing is cool. I guess all the unconnected speakers make things worse as well.
I think got used to this after a while and now I started liking the AMT again🙂
It also matters where I listen (as expected). Closer than now is better.
The thing I do not like that much - and that was the experience with the long planars I tried - is the narrow vertical directivity.
Now I am listening to some favorite tracks and it is definitely not bad, especially the efficiency is nice, the amp lights barely flash.
The "center channel" is not connected, but the illusion is that it is the only speaker playing is cool. I guess all the unconnected speakers make things worse as well.
I think got used to this after a while and now I started liking the AMT again🙂
It also matters where I listen (as expected). Closer than now is better.
The thing I do not like that much - and that was the experience with the long planars I tried - is the narrow vertical directivity.