HELIOS Speaker Kit

@gabrittain  what is your point to post this?  if you had to summarize in your own words what is your opinion of the doppler distortion articles, posts, opinions, actual audibility ?

Regarding the Beryllium tweeter, Beryllium is a highly efficient material that can be used for speaker diaphragms. Beryllium tweeters are known for their clarity and detail, but they can also be harsh-sounding vampire survivors if not integrated properly into the speaker.

I just today finished building the Textreme version of this speaker. I ordered the kit through Madisound (drivers/crossovers) and the birch flat packs from Speaker Hardware. 

This build was a challenge, primarily because the biscuit cuts of the supplied flat packs resulted in almost zero of the panels mating up flush. Some of the cuts were so bad I was tempted to request a refund and attempt the build myself despite being a novice wood worker. Alas, I am a busy man so I instead opted to sand the panels flush. The only way the flat packs differ from the SB drawings (aside from aforementioned cuts) is omission of the three small rectangular brace pieces. I didn’t want to omit those so made some out of some 1/2” void-less birch I had around. To damp the panels I used a total of 7 sheets of Soundcoat dampening (some Bitumen-like stuff) that can be bought from Parts Connexion. For the fill I used wool batting. Haven’t experimented with volume of batting yet. Thus far, just enough batting to cover the bottom and back sides of the cabs. On a side note, after using Weld Bond glue for this build, I will never again go back to using wood glues for projects where I am concerned about runs. 

So in short, these speakers sound incredible from about 80Hz (my guesstimate) on up. They easily compete with some of the </= $15K speakers I’ve heard from the commercial brands. The problem I’m having is a lack of bass below that 80Hz range. Perhaps it’s because I currently have the passive radiators facing inward toward each other? Maybe they need break-in too? What do you all think? I was really expecting more bass out of these.