First? clone of Alpair 10.3 hybrid

[abf]

Hello my new friends.

I am reading here time by time for several years.
I just registered to present my build of Spassgeneral's hybrid design.

As I am a big fullranger fan I decided to try the Alpair 10.3 hybrid tml/horn.
In general the downside of single driver designs is the little membrane area which compromises the bass authority. Using bigger fullrange drivers beam in hights so it is always a compromise.
the two driver approach seems to be a good solution to me.

Instead of using bb ply I decided to do a double walled, sand filled enclosure of mdf.

 

[abf]

Front and side walls ill be of 10-6-10 mm thickness.
So in total 26mm with a 6mm sand inlay.
here the 6mm frames for the middle layer.

then laminating the 3 layers.
and finally inserting the quartz sand.

top, bottom and back will be simple 22mm mdf

 

[abf]

so the heavy part is done.
preparing the double walled parts was a time consuming work.
hope it is worth this effort.


glueing the parts to finally build the cabinet was easy.
only one none 90 degree cut. a little bit fiddling until the right angle is adjusted at the table saw.

 

[abf]

almost finished cabinets.
I will attache some bracing though
time to line the inner walls with felt.

 

[abf]

exactly routed cutouts for the drivers.
chamfered corners at the front.
you can see the three layers of the side walls.

 

[karl5150]

What's the plan for the final finish? Paint, laminate, or?

 

[abf]

Hi Karl,
I am going to use hammer finish paint.
I think this will give good results for an occasional painter and cover faults and small imperfections.


I wanted to implant some neodym magnets to fix some kind of cover.
Has anyone experience with these?
What would be the recommended size to hold a front cover of about half size of the front?

 

[plund]

ABF, Magnets to hold grills on... very good choice. I would use at least 8 imbedded in the grill and another 8 imbedded in the baffle. If you cover them with veneer or paint they will look nice and hold very well. You can experiment with the holding gap distance... the smaller the gap the stronger they will hold, depending on how powerful your neo magnets are. The last magnets I used were 7mm x 3 or 4mm.
Pete

 

[chrisb]

The little neo magnets I used to use were 1/4 x1/4”, imbedded into corners of 1/4 or 3/8” MDF frames. Carefully inset flush into front baffle, they were easy to cover with veneer, and depending on length of frames, one in each corner - total of 8 per enclosure - were quite enough.

 

[abf]

thank you both for your suggetions.
I ordered 8x8mm neodyms. Curious to see how strong these are

 

[chrisb]

Very strong - pay attention to polarity. I always cut the grille frames first and taped them to the baffle before drilling holes in both with brad point/forstner bit. Experiment on scraps to set depth in baffle approximately 1mm deeper than magnet, and add a drop of white wood glue just in case it’s a loose fit. Then use a block of wood to set the magnet flush with baffle.

 

[planet10]

...hybrid design….

Typically we call those WAW — Woofer assisted Wideband (encouraged over the old FAST term).

Hi abf,

Instead of using bb ply I decided to do a double walled, sand filled enclosure of mdf.

Must have made your back sad. And w a well designed BB box, maybe not better.

Does the A10.3 have its own subenclosure — i didn’t see one, and it is likely necessary.

Did you model the line? Looks vaguely simialr to FHXL with a shorter horn but the same kind of choke and mouth.

People are usually quite happy with the bass from A10.3 in FHXL.

What bass driver are you using.

Magnets are great for the grills. It is really neat how the grills snap into place as long as you get them close. I pestered Chris for about 2 years, once he tried it, nothing else ever again.

dave

 

[abf]

Hi Planet10.
No this is not waw design.

This is a double alpair 10.3 in a transmission line / horn design.

Recently member Spassgeneral introduced his design.

Look here:
Markaudio Alpair Hybrid

 

[planet10]

OK, that answers all my questions. Are you going to experiemnt with the different way sof wiring the driver?

dave

 

[abf]

I am wiring the same way as Spassgeneral did. So I can run the drivers in series or parallel.
My amp is a british Myryad MI120. A transistor amp with quite a lot of power.

 

[planet10]

What about rolling off the bottom driver to avoid comb filtering at high frequencies?

http://www.planet10-hifi.com/downloads/Dual-Driver-Wiring.pdf

dave

 

[abf]

Planet10,
The link does not work for me.
Can't download the pdf

 

[planet10]

I clik on it it works. You could try the usual fixes like clearing your browser cache or copying & pasting the URL.

dave

 

[abf]

Really strange,
Now the link works. Without doing anything on my side.

That is very interesting.
A very easy way to implement bafflestep correction with just one part.
The enclosure design seem to enforce bass so much that there might be no bafflestep correction needed. Spassgenerals sims look very promising.
I like the idea to have no parts in the signal path.

Comb filtering might be an issue, though.
Which frequency will be affected in this design?
How strong is this effect?
And how will this be recognized hearing music?

 

[Spassgeneral]

Hi abf!
Nice to see a build of my design. I'm sure you will not be disappointed.
You put much effort into the enclosures. Must have some weight
The enclosures look really good.
The cut outs look perfect.
I think this is the most difficult part. The alpair's frames do not allow to large holes.
I did not have a router to get those perfect results.

Felt is about 10mm?
When the drivers are run in you can experiment with some light wadding to tune the sound exactly to your taste.

Thebspeakers do not need a baffle step correction.
I run them without any filtering.

I am still deeply impressed by the sound feeded by an ASR emitter.