My 19 build begins in earnest - H811b arrives....

**Coelacanth** · June 18th, 2015, 11:44 PM

The 811 I ordered arrived the day before yesterday - all the way from the U S of A to little old New Zealand....

It is in very good condition - but not for very much longer... Tonight I will split the horn into its two original castings and begin adding 'shape' to the outside of one of these castings, making it more 'copy-able' for my router-based wood copying machine.... I will hopefully end up with four 'sides' copied nearly exactly, which will then be stuck together to replicate the inside of an 811b, and look a little different on the outside.

I will also make some moulds out of the halves while the horn is apart.

My darling wife has been a bit against the idea of an audio project, but we sat last night and listened to the tiny speaker from my Samsung S5, pressed up to the throat of the 811 - ok, lets face it, it was pretty low-fi - but that horn magic was very real and present. Imagine what they can do with real drivers? I asked... Now she is eager to find out.....

**Altec Best** · June 19th, 2015, 12:01 AM

Originally Posted by Coelacanth

The 811 I ordered arrived the day before yesterday - all the way from the U S of A to little old New Zealand....

It is in very good condition - but not for very much longer... Tonight I will split the horn into its two original castings and begin adding 'shape' to the outside of one of these castings, making it more 'copy-able' for my router-based wood copying machine.... I will hopefully end up with four 'sides' copied nearly exactly, which will then be stuck together to replicate the inside of an 811b, and look a little different on the outside.

I will also make some moulds out of the halves while the horn is apart.

My darling wife has been a bit against the idea of an audio project, but we sat last night and listened to the tiny speaker from my Samsung S5, pressed up to the throat of the 811 - ok, lets face it, it was pretty low-fi - but that horn magic was very real and present. Imagine what they can do with real drivers? I asked... Now she is eager to find out.....

I give you an A+ for the ingenuity of getting the Mrs. hooked into your project... Hook,Line and Sinker !

GM · June 19th, 2015, 01:58 AM

So, is this the official DIY M19 speaker build and do you still plan to just basically replicate it or a MLTL instead per here?: Way OT.. an afternoon with some Klipsch's.....

GM

**Altec Best** · June 19th, 2015, 03:03 AM

Before you get started take a look at this Yahoo Group by Martin King !

Quarter Wavelength Loudspeaker Design

**Coelacanth** · June 19th, 2015, 03:24 AM

Hi GM, I am still open to the MLTL thing, in fact I would prefer to go that way. Just been waiting for your input.. not sure if you are getting my emails? Perhaps not. I will go the 19 duplicate route if the mltl option is beyond my ability to resolve.

**Coelacanth** · June 20th, 2015, 06:24 AM

Anyone ever seen an Altec 405.5a horn? Well, here you have it!

Note the grey-green area forward of the throat, no doubt caused by rogue abrasive soundwaves - I believe the previous owner may have owned solid state amplifiers and been a Celine Dion fan.

But seriously, I wonder what caused that? Its over the paint, rather than paint missing...

The horn came apart very easily - all welds only superficial - barely penetrating the casting, so as soon as I ground back the bead, the two sides virtually sprang apart. The only notable exception to that was on the mounting flange, where the weld had to be hacksawed.

The halves are entirely re-usable and undamaged other than light grinding marks - and I cannot see why I wont be able to weld them back together if needed.

For now I have my 'mothers' to copy in timber. Will keep you posted, if on the off-chance y'all can forgive me for maiming a sacred Altec horn. Its for the greater good. The Greater Good.

**oface1** · June 21st, 2015, 03:00 PM

I am going to enjoy this post! Keep the updates coming!

GM · June 26th, 2015, 10:52 PM

Originally Posted by Coelacanth

Hi GM, I am still open to the MLTL thing, in fact I would prefer to go that way. Just been waiting for your input.. not sure if you are getting my emails? Perhaps not. I will go the 19 duplicate route if the mltl option is beyond my ability to resolve.

Greets!

OK.......

?? I?ve only gotten one PM and I responded to it plus responded to your Qs in one of the earlier threads, so AFAIK, this one is all that?s left.

What's wrong with Westend's except done up in a stretched version of the M19?

GM

**Coelacanth** · June 27th, 2015, 01:53 AM

Hi GM thanks for coming back to me. I did send an email but it must have gone astray... The stretched 19 idea is spot on what I was thinking. I need some help with the interior box dimensions for the GPA drivers however. Could you be called upon to help there? I have the TS parameters from GPA, who assure me they are pretty close.....

Thank you Sir, and feel free to tell me to bugger off if I am asking too much :-)

GM · July 1st, 2015, 03:05 AM

Greets!

You're welcome!

Well, since you're already comfortable with the 19's width, depth, horn section, spacer/pedestal, nothing except the bass bin height changes along with the vent, bracing.

The driver will still be the same distance down from the top to preserve all of the aspects of the XO 'voicing' save one, so what?s the max height the centerline of the horn can be from the floor and roughly how high is ya?ll?s seated ear height?

GM