Something stirs in the Undergrowth

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Nick
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#2626 Re: Something stirs in the Undergrowth

Post by Nick »

though I was thinking a little earlier,
Yep, but I looked back two pages, and while there were other places as you say, they would have all left it hanging, or taken some bits that should have stayed here. So I thought your post was the least worst place.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
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IslandPink
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#2627 Re: Something stirs in the Undergrowth

Post by IslandPink »

Ok, not a problem.
"Once you find out ... the Circumstances ; then you can go out"
chris661
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#2628 Re: Something stirs in the Undergrowth

Post by chris661 »

I've put a post up: http://www.audio-talk.co.uk/phpBB3/view ... 48#p176066

Which outlines the implementation of FIR processing, with real-world results.

Chris
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IslandPink
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#2629 Re: Something stirs in the Undergrowth

Post by IslandPink »

Yes, I'm just thinking about posting, I've been out, but mulling over a few things on the bike.
"Once you find out ... the Circumstances ; then you can go out"
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IslandPink
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#2630 Re: Something stirs in the Undergrowth

Post by IslandPink »

I feel another horn coming on.
Looking at the length/width expansions from the horn I mentioned above -
Concept_1p9m.jpg
..it lends itself to a straight test version, using existing ply and fibreboard around the house. The starting piece will be lower face, cut from some 18mm ply at 1220mm length that's left over from the Horst Moeller double-horn. This should provide a solid foundation for everything else.

The straight one can be used for tests both on the Behringer and by ear, to establish if the combination with the Yuichi at one-wavelength setback sounds any good.
I don't anticipate that a future one with one 90° bend in a fairly 'thin' part of the height expansion will sound much compromised, vs. a straight one.

SimonC, give me a shout if you want to see the Hornresp txt data for this expansion :)
"Once you find out ... the Circumstances ; then you can go out"
Cressy Snr
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#2631 Re: Something stirs in the Undergrowth

Post by Cressy Snr »

IslandPink wrote: Sat May 30, 2020 1:00 pm I feel another horn coming on.
Cue DTB. :wink:
Sgt. Baker started talkin’ with a Bullhorn in his hand.
steve s
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#2632 Re: Something stirs in the Undergrowth

Post by steve s »

Cressy Snr wrote: Sat May 30, 2020 2:34 pm
IslandPink wrote: Sat May 30, 2020 1:00 pm I feel another horn coming on.
Cue DTB. :wink:
Those where days...
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#2633 Re: Something stirs in the Undergrowth

Post by IslandPink »

No sign of him ...
Here, it starts again. Base panel from 0 to 112cm of expansion. Yes, know there's s notch at the small end, limitations of the panel I had. Some scrap wood and epoxy will fix that.
Horn_1p9m_base1.JPG
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vinylnvalves
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#2634 Re: Something stirs in the Undergrowth

Post by vinylnvalves »

These two articles may be interesting from Troels.... he is using a DSP and plate amp for bass duties only in the first article and ditches the valve amp in the second. Might have some synergy with what you are currently doing Mark... (to be honest I seem to not understand what your upto - building another horn?)
http://www.troelsgravesen.dk/FUSION-BI-AMP-DSP.
http://www.troelsgravesen.dk/FUSION-3.htm
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Dave the bass
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#2635 Re: Something stirs in the Undergrowth

Post by Dave the bass »

steve s wrote: Sat May 30, 2020 3:01 pm
Cressy Snr wrote: Sat May 30, 2020 2:34 pm
IslandPink wrote: Sat May 30, 2020 1:00 pm I feel another horn coming on.
Cue DTB. :wink:
Those where days...
Hot dang , a missed opportunity for a pfffffnarrrrr and Kenny W gif.

Sorry!
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IslandPink
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#2636 Re: Something stirs in the Undergrowth

Post by IslandPink »

Yes, Dave, too late now - sorry.
vinylnvalves wrote: Mon Jun 01, 2020 12:36 pm (to be honest I seem to not understand what your upto - building another horn?)
Yes, well there is a picture of a concept up there, then a description, then a picture of the first wood being cut.
If it looks like a horn and quacks like a horn .... oh hang on, hopefully not :)

As usual I'm not doing one thing ( only ) at a time.
The DSP/FIR option I will wait for someone to demo me a meaningful version of.
The horn i can make ( as a proto ) now .

The concept is an amalgamation of all the stuff I learnt on the folded horn variants plus the double-horn from Horst M.
I was looking at 2.5m long, a few weeks ago, but it becomes a problem for packaging and for time-alignment. 1.9m long, with a decent mouth size ( 3300cm^2 ) seems to support 100Hz with flattish amplitude and low group delay over 100-800Hz. [The double-horn build showed that 9ms delay at about 250Hz is definitely audible, so helped define what isn't possible with back-horns or wavelength offsets. Also the small mouth sizes, even with floor-loading, do not give the proper horn sound I was hoping for].

This concept of the lower-mid horn is also based around the max 'intrusion ' into the room of about 1.5m from the sides of the bay windows. With the 'inverted L-horn' concept, there is more freedom to get the upper-mid horn nearer the wall. With this, I can use only 1 wavelength step at 600Hz crossover. This is better than the Vox Olympian which has 2-wavelengths at 500Hz. The only downside then is managing the upper-mid reflections off the bigger horn's upper surface. I am hoping with some curvature at the lip and/or reflectors/absorption, this can be kept acceptable.

There will be a small chamber of about 1 L at the throat/driver that ought to give a LP rolloff of this horn starting at about 500Hz, tests will confirm how effective this is for the final versions if they go ahead.
"Once you find out ... the Circumstances ; then you can go out"
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Paul Barker
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#2637 Re: Something stirs in the Undergrowth

Post by Paul Barker »

watching with interest
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IslandPink
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#2638 Re: Something stirs in the Undergrowth

Post by IslandPink »

Not a lot of progress this week, too much work, but a couple of side panels here for the first 82 cm.
It took a fair while to work through the data and carefully mark these out.
I'm aiming to get most of the first metre done in 18mm ply, but then see if I can risk a few pieces of fibreboard on the larger curved sections, with some bracing struts inside.
Horn1p9m_side_panels.JPG
"Once you find out ... the Circumstances ; then you can go out"
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#2639 Re: Something stirs in the Undergrowth

Post by IslandPink »

After further fettling and some assembly -
Trimming will come later. Also started making the first top piece which will also be the interface and entry aperture for the driver.
Horn1p9m_Sun7th.JPG
"Once you find out ... the Circumstances ; then you can go out"
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#2640 Re: Something stirs in the Undergrowth

Post by IslandPink »

This bit was fiddly -
Horn1p9m_inputpanel.JPG
"Once you find out ... the Circumstances ; then you can go out"
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