1803B horn plans available?

**Audiomind** · January 31st, 2013, 06:50 AM

Originally Posted by Cal Weldon

Audiomind, I agree using the foam core from your local dollar store is the way to go at least to start. We have been having a tom of fun experimenting with the Cornu style cabinets. Without the foam, those would be beyond many of our means. So what's it going to be, the 1803? I can give you all the dimensions of the waveguide as well if need be.

Yes I want the 1803 for sure. Have two different pro wood shops at my disposal, I am psyched for this one.

**Audiomind** · January 31st, 2013, 07:07 AM

Originally Posted by Cal Weldon

I will take many photos as well if I am doing the take off. I will email those directly as I can't post them all here.

Yes, please do not hesitate to email me direct with anything you like about the 1803B horn.

Pencil tracings of both throat adapter ends indicating the dimensions on the tracing would be nice.

I know it will take a little time to unbolt it all, trace, etc. do your best when you can, I really appreciate it.

**Panomaniac** · January 31st, 2013, 11:01 AM

It's OT, but I don't see what being able to hear up to 18K has to do with Alnico or not. Extended top end hearing may help you evaluate super tweeters, but has little to do with good perception and learning what to listen for. Yes, I prefer Alnico drivers, but I don't think I could ever hear above 18K, even in my youth. I don't think the differences are up that high, they are more in the midrange.

As for kicking the multicells out of the living room - kick my way! I sit not more than 10 feet from mine and have no problem. Neither has anyone (audiophile or not) who has visited. Quite the contrary. Sure, I'd love a bigger room, but that's more to do with room acoustics than the multicells.

**alancohen** · January 31st, 2013, 11:43 AM

Originally Posted by Panomaniac

As for kicking the multicells out of the living room - kick my way! I sit not more than 10 feet from mine and have no problem. Neither has anyone (audiophile or not) who has visited. Quite the contrary. Sure, I'd love a bigger room, but that's more to do with room acoustics than the multicells.

My adventure with Altecs started a few months ago when I visited Kevin (KAB-USA) for some turntable stuff and got to listen to his horns. 1003s I believe. I had never heard anything like that before. It was like a huge wall of sound gently washed over the entire room. They were not more than 9' away and towed out if I recall. The sound was breathtaking. They might sound even better in a bigger room, but they still sounded great where they were. I'd sign up for that any day. Wait, I have already

**alancohen** · January 31st, 2013, 01:01 PM

Originally Posted by Cal Weldon

I'll go look again.

EDIT: Found them:

First at post 712 And Now For Something REALLY BIG - Page 18 - diyAudio is the plot and post 716 And Now For Something REALLY BIG - Page 18 - diyAudio has a trace of the curve but as we age we forget things, I now note that is for the 1005 horn and I don't know the difference in length if any. The mouth size is the same.

EDIT2: Looking at the link provided before, they are indeed the same. Don't be fooled by what looks like a 0.5 inch difference. You'll figure out why. So there you go. All you need for a 1505 except the waveguide.

EDIT3: Check this post as well. And Now For Something REALLY BIG - Page 19 - diyAudio

Excellent! That's perfect, Cal.

So let me see if I get this: All cells for all horns are basically the same curve. What defines a 500Hz from a 300Hz is the length of the cell...yes? So you can turn a 300Hz cell into a 500Hz by trimming off the front?

**Cal Weldon** · January 31st, 2013, 01:06 PM

Maybe, not sure. Am heading into the dungeon now to begin the plotting.

**alancohen** · January 31st, 2013, 01:15 PM

Originally Posted by Cal Weldon

Maybe, not sure. Am heading into the dungeon now to begin the plotting.

I think you mean "plodding".

**Audiomind** · January 31st, 2013, 01:23 PM

Originally Posted by Panomaniac

It's OT, but I don't see what being able to hear up to 18K has to do with Alnico or not. Extended top end hearing may help you evaluate super tweeters, but has little to do with good perception and learning what to listen for. Yes, I prefer Alnico drivers, but I don't think I could ever hear above 18K, even in my youth. I don't think the differences are up that high, they are more in the midrange.

As for kicking the multicells out of the living room - kick my way! I sit not more than 10 feet from mine and have no problem. Neither has anyone (audiophile or not) who has visited. Quite the contrary. Sure, I'd love a bigger room, but that's more to do with room acoustics than the multicells.

Panomaniac, you are right on the 18K+, please forgive my alnico rant, I should have started another thread, I hope not many respond until move the thread, I really was just rambling. I should probably have the administrator move the post to a new thread.

Yes alnico is more noticeable from the bottom of the comp driver range as you say, but I was addressing problem of the harsh highs on the Synergy.

In conversations in the past I have come across people who actually say they can't hear a difference using alnico magnets!

It really gets to me when key industry people say this and we are left with the crap companies are shoving to us.

I easily hear the difference of alnico every time and even have done the silly level matched ab/x and get it right 100% of the time using a small piece of a music track that I learn what both a and b sound like before the test if it is close (which it is never close). My lord I realized I just opened the ab/x genie. people ignore this post until I get it moved.

I really do love the centererd driver multicells and can live with them in the living room for a while, but that "driving by a guard rail shushing" gets old after a while to me. I said kicked out of the living room, not kicked to the curb!

**Audiomind** · January 31st, 2013, 01:40 PM

Originally Posted by alancohen

Excellent! That's perfect, Cal.

So let me see if I get this: All cells for all horns are basically the same curve. What defines a 500Hz from a 300Hz is the length of the cell...yes? So you can turn a 300Hz cell into a 500Hz by trimming off the front?

Anyone out there correct me if I am wrong but I don't believe you can just lob off the front, because I believe that would ruin the whole expansion rate.

**Audiomind** · January 31st, 2013, 01:48 PM

Originally Posted by alancohen

I'd be interested in that 1505 plot. I have GPA 802Gs so 500Hz is as low as I'd be going with my system. I can dream about 300Hz, but it's not likely going to happen without a lottery intervention. I would likely do a 1205 with a throat for a 1" driver. I might have the only 1205s this side of the Mississippi...or the other side.

I can also do just as well with photos. I build model airplanes from scratch and have drawn accurate plans from photos taken at museums.

Alan,
1. A message to every one out there about designing horn systems. If the cuttoff is a certain frequency, like say 500hz you can't cross there even with steep slopes. you must cross a little higher. this is what makes the 1803B so attractive even though the size is monstrous, gets more compression driver sound and less top of the range ugliness from the woofer.

2. Making something look similar is one thing but this device is an actually working sound manipulator and the measurements are super critical.