HELIOS Speaker Kit

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.

@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 ?

Jeff Bagby was one of the most talented speaker designers to ever hit the DIY community.  All of his designs have been carefully thought out and perform very well--both by ear and by measurements.

To say that "he has no idea what he is talking about which means he has no idea how to design a loudspeaker" is shameful and uninformed.  

Mijostyn you are beginning to sound a bit rude and boring.  Would it make you feel special to tell me my lunch doesn't taste good, hahaha!!!

We are saying the speakers sound great, and you are saying they are croaking, yet you have not heard them.

The designer had extensive experience designing speakers and provided the designs at no charge.  He wrote that the distortion on these was so low it was difficult to measure at normal volumes.  In fact, the lowest he has ever measured.  He said this speaker design may have been the best he ever built.

The manufacturer, SB Acoustics, asked him to make this design for an audio show and it received a lot of positive feedback.  One of the reasons I purchased the kit - all the comments I read from people who heard the speaker, not one said it was "ok", "not too bad", but every comment used words like "amazing" and "best ".

@boostedis Wrong strategy. The ONLY way a small woofer has of making more bass is by increasing it's excursions. Price has nothing to do with it. Longer excursions create more distortion, much more distortion in the most sensitive part of the midrange. Read up on Doppler distortion. Systems set up like you suggest are only good at very low levels, turn them up and they become painful to listen to. If Jeff handed you that line of garbage I suggest you sell them, he has no idea what he is talking about which means he has no idea how to design a loudspeaker. 

If you want to clean things up and add some headroom you get a digital two way crossover and cross over to your subwoofers at 100 Hz. If you only have one buy another. There is no other way to make a small loudspeaker sing at high volumes. Right now you are croaking.

@mijostyn You are correct that the Helios crosses the woofer higher and the tweeter lower to overcome the usual challenge of a 2 way design using a larger woofer for bass extension at the expense of linearity. With that said, Jeff Bagby has managed to overcome that challenge with careful use of the PR to control woofer excursion while also adding a little to the low bass response which with my setup, the sub comes in at 40hz and is barely noticeable because the Helios digs quite deep before needing help! Jeff said he tested them to 113db and the distortion was so low that it boarded on immeasurable! That is why you use a $500 tweeter and $400 bass driver. 

@rop45 Glad to hear your Helios kit is living up to the hype!! It’s always refreshing and reassuring to know that I wasn’t crazy when I fired mine up and realized they were better than some $10K commercial speaker designs I have heard recently. Keep us posted on the final build. I used either a 19” or a 21” Pangea Audio stand for mine and it definitely smooths out the tweeter response and widens the soundstage. Vocals should be centered just above the tops of the speakers which a very spooky affect that gives the impression of a singer elevated on a stage with you in the first or second row! Truly magical!

And ONE DAY after the Pine boxes are functioning, I get the call, BIRCH material is ready for PICK UP!!   😆

Helios test run:  (Pine boxes in previous post)

I knew my boxes weren't perfect but I couldn't wait for my birch to arrive.

I figured at least test if the pre-assembled crossovers and speaker drivers were working without any problems.  Maybe get an idea what the Helios sound like albeit in an inferior box.

Everything worked great. Meniscus Audio did a Great Job with the crossovers, with answering questions, with getting me Satori OEM magnetic grills at the last minute, helped me out whenever I needed anything.

Initial impressions - Bass is Enormous, tweeters are a bit rolled off.

But have to keep in mind, with my triangle boxes directly on the floor, center of tweeters were only 15" off the floor.  They did have 30 degrees backward tilt.  The tilt helped to get the sound up higher, but at the same time it's probably voiding all the intentions of the crossover designer.

The bass is probably being reinforced by being too close to the floor.  Once again, contrary to the designers intention.   Bass was also a little bit too boomy for my liking?  I figure the thin pine boxes with no damping were guilty here.

After some time listening I can say that even my poor execution of this speaker kit sounds great!  Bass is approaching the performance of my (2) Focal 12" woofers.  With no actual data, I am thinking everything the 12"ers could do at 25hz, the Helios can do at 30hz.  Moving up to mid-bass, the Helios is even more Grippy than my old Dynaudios.  So when you consider all of the lower end, under normal operation, the Helios is equal to my home built 6 cubic feet Focal/Dynaudio monsters.  

The tweeters have done nothing wrong so far.  They are not too bright.  I am making the reasonable assumption that when I get them into the as-designed box, and as-designed elevation they will only sound better and better.

As they sit right now, they can sound like musicians are actually in the room.  They are outperforming or at least matching anything I have ever had.  I am expecting after I control the bass just a little bit with heavier boxes and damping material, I will have more to say about the tweeters shining through...

Helios in the House!  Speaker kit arrived but I was still waiting for my Baltic birch, so I decided to build "test" boxes.  Found scrap pallet with 7/8" thick plywood from Italy! 30"x75" one sheet.  Dreamed up an equilateral triangle shape for the cabinets.  Made (4) triangles, approx 24" on each side.  These are side panels for cabinets.  One of these on each cabinet has the PR centered in it.  Next, spent $38 for (2) 1"x12"x72" pine boards - paint grade - multiple pcs joined together.  Outside dimensions were true, actual thickness 11/16".  Cut the boards into (6) pcs @ 21"5/8 overall length, both ends mitered at 60 degrees, so reducing the length of the side that faces to inside of cabinet to maybe 20"?  I can't remember.  I know the volume is exactly 1.2 cu ft so that would be a way to verify everything.  Alternating butt joints allows 3 pine boards to make front baffle, back & bottom in a perfect triangle.   Chose to buy a $200 pin nailer (and glue) rather than an elaborate system of clamps, ha!  Hey! I will use it again sometime?!  So the pine boards make the triangle, the 7/8 ply is glued on each side.  The plywood then trimmed to fit, and later rounded over.  PR recessed 3/8" into the 7/8" plywood.  Tweeters recessed 3/16 (+) into the 11/16 pine front baffle.  Woofer is NOT recessed, I was thinking 7/16" recess into 11/16 was cutting out too much.  Have to screw the woofer down to SOMETHING.  Dimensions down from top of cabinet match Meniscus drawing.  My cabinet width is about 2 inches wider, but it is what it is.  Two 5/16" holes drilled for the "Big Posts" on the back.  Jasper Jig for Router was amazing.  When you have to change back and forth to several different diameters and have confidence they will be accurate, worked great.  My last cut for through hole on tweeter was not possible because my router base interfered with Jasper holes.  That could be due to me using a router with no Plunge functionality?  Finished with jigsaw.  So the moral of the story - I love my test boxes even though I understand 11/16" pine board with no bracing and no damping material is the WORST possible material to choose for a speaker baffle!!  Just remembered I did add small piece of oak 3/4x2x12 between woofer and tweeter cutouts, but not much bracing.  Next post will be sound evaluation...

@milostyn

In general, you are correct, but I am hoping there is MAGIC in this design that defies rational explanation!  :).  Designer has stated the distortion is so low on this speaker that he could barely measure it - like he has never seen before.  Also, that it is likely best speaker he has designed over 20+ years.  Thank you for the well wishes!

@rop45 , it is not just bass! Reproducing bass requires a woofer to take long excursions. The smaller the woofer to longer the excursion. The Helios is a two way speaker with a woofer that is running higher and a tweeter running lower to get to the single cross over point. The woofer is really a mid woofer. The long Bass excursions cause Doppler distortion of everything else the woofer is reproducing. If you do not know what Doppler distortion is google it. Transferring the lowest frequencies to another driver gets rid of the distortion entirely and increases the headroom of the system. For full range and two way speakers the improvement is quite dramatic. Less so for 3 way systems. 

Have fun building them and good luck with the project.

Trigger pulled !  Money is where my mouth is !  Helios kit on order !  

@mijostyn 

I agree with you, but I don't have to match the bass output of the old ones.

if the Helios is better, or as good as my originals in 3 or 4 important categories, falls a bit short in the bass, but is still impressive for it's size, I will consider that a total success.  I just returned some REL subwoofers that sounded really great.  I am enjoying the open floor space.  :)

@rop45, the Helios drivers are very good ones but even with a passive radiator that little woofer is never going to be a match for a 12" Focal driver. What I would do is build the speaker without the passive radiator (which will take redesigning the box) and cross over to  subwoofers  at about 100 Hz. 

Speakers now are Thiel CS 2_2 and Maggie LRS, which I am sure will be displaced by the Helios.  Historically, up until a month ago, I had home-built monsters that I designed along with some help from Madisound for the crossover.  Dynaudio soft dome and (2) 17cm mids per side, (1) Focal 12" woofer.  Absolutely awesome sound, only downside is approx 6 cubic feet measured to outside of cabinet, truncated pyramid shape. Taking a word from Jeff Foxworthy,  I USED TO COULD lift them a lot easier than I can now!  Memories of these is what the Helios has to compete with!  If I can get them built correctly, I think they will be up to the task, at least they will check several of the boxes.   Thank you once again.

Your cabinet thickness on most sides should yield quite an inert structure. The No-Rez is probably the best material to use for the CDL layer. I wanted to experiment with the Polyurethane because it was easily sourced at local Box stores. I applied it to the outside of the inner panels by troweling to about 1mm thickness and then securing the outer box (1/2 solid panels). Don't skimp on the internal bracing side to side as well as tying the center brace to the top and bottom panels. 

1) Vocals are really the strong suit of this speaker. They sound very much like the singer is present for both male and female. They raised the perceived level in space of the singer to a higher point in the room as if you are seated and the singer is higher than you on a stage. Almost an eerie sensation because they are there in the room with you! There really is no weakness, but they are darker (because of the warmer midrange) than my Dali Helicon's. Make sure you give plenty of break-in time before you evaluate the sound as they will improve over several weeks of use!  

2) Outer cabinet is 11Wx19Hx15D so 1.5CF I was told to not count the bracing in your calculation. 

3) I purchased Pangea DS400 20" stands. Perfect for my seating position.

Good Luck. I think you will be quite happy. What speakers do you have now?

@boostedis ​​​​​​

Thanks so much for sharing!  

I have drawn myself a "flat pack" on AutoCAD and sent the DXF files to a professional cabinet maker who will cut it out of Baltic Birch plywood on his CNC router!  Have not ordered the drivers, but there is no going back now!

I did not see any of Javad's Facebook posts, but I am just working from the photograph.  The finished speaker with the edges of plywood visible everywhere.

As overkill is the theme, my box will be 1.5" thick on 4 sides, 1.4" thick on one side, and .71 inch on the last.  I wanted to preserve the narrow front baffle.  The thinner side has bracing on it and will have to do.  I guess I can add No-Rez to it during the build process.

I like your choice of box materials.  Mine was much less efficient, having to purchase 3 sheets of 5'x5' Baltic birch, but the good thing is there will be some left over to build matching stands!

Questions for you:

1.) How would you rate the vocals, does strong midbass interfere?

2.) What is your box volume?  I think I have 1.35 cubic feet before bracing and 1.2 cubic feet after bracing.

3.) What height do you have them set at? To center of tweeter.

Thanks again!

I forgot to mention that these are not at all efficient! Probably in the 83-85db range. I tried to power them with a 60wpc Tube Amp and that didn't go well at all! They didn't come alive until I hooked them up to my Mark Levinson 585 and now they sing. 

I just completed the Helios build this month. I went a little overboard with cabinet bracing (I went off scrip from Javad’s design but basically the same). I built basically a box within a box with 3/4" Baltic Birch inner box and bracing, and 1/2" solid wood outer box with a constrained layer damping material sandwich between the boxes. The goal was to create as inert an enclosure as possible. The results were quite good with the knuckle rap test showing the cabinet is as dead as any that I had knocked on (subjective impression) outside of a Magico (aluminum) or Alta Audio (Damp-hard, whatever that is!). I went with the highest spec components that were on offer at Meniscus which came to about $2200 and probably another $500 for the cabinet materials.

The sound after some break-in is exceptional! I have recently auditioned the new B&W 800D4 range (all of them) and I am struggling to say that the B&Ws are better! The Helios is not as bright as the B&Ws but with stronger mid-bass energy. The Beryllium dome is quite honest. If the source material is shimmery, then this tweeter will reveal that. If the source is laidback the presentation will be such. I would not go so far as to call them laidback, just true to the source material. Like any speaker then can be changed to suit by the Amplification of choice. The bass and mid-bass is the speaker strong suit especially for a standmount. They turned out to be easily good enough to replace my Dali Helicon 400s which are a quite good speaker. These speaker absolutely disappear in the room! The imaging is as good as the Magico A3s with a rocksolid center stage, with vocals placed slightly higher than I'm used to in my room and solidly behind the front wall. If imaging is your thing, you won't be disappointed! My bias is not based on the fact that I built them as I was really wanting them to not be as good as they ended up because I really wanted a commercial brand to be better, but that is not at all the case here....