Up-Firing Metronome in Larson Pyramid Style

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Cressy Snr
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#1 Up-Firing Metronome in Larson Pyramid Style

Post by Cressy Snr »

So many speakers, so little time left. :(
Watch this space gents.
Last edited by Cressy Snr on Tue Jan 03, 2017 8:00 pm, edited 1 time in total.
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#2 Re: Up-Firing Met in Larsen Pyramid Stylee

Post by Cressy Snr »

Two simultaneous projects,
one, my 4ft straight quarter wave resonator from the other thread, the other a Doc influenced semi omni,
up firing bass/mid/ front tweetered, folded quarter-wave tribute to the late 60s Danish, speaker, the Larsen Pyramid.
The Larsen Pyramid was my original inspiration for the shape of the Metronome, way back in 2006. It has to be done!
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#3 Re: Up-Firing Met in Larsen Pyramid Stylee

Post by pre65 »

You will be busy Steve.

Is this what you mean ?

Image
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#4 Re: Up-Firing Met in Larsen Pyramid Stylee

Post by Cressy Snr »

Yes, that's it

Too much forum blathering, babbling, talking bollocks for the sake of it, failing to take a step back, think things through, and not enough actual building action, has resulted in zero progress on the speaker front, and a massive load of other fucking hassle I'm not about to go into. With my mental health history it has done me no good at all and TBH with all of you, it damn near tipped me over the edge a few days ago. Let's just say a national organisation that people in a desperate state of mind often talk to, helped out enormously. I'd appreciate a bit of privacy at the moment. PMs are turned off.

Sooo......anyway...As far as speakers are concerned, I've been talking a good job for too long; DO something con structive rather than de structive is the way forward for this punter.

In the meantime, pics will go on as things progress but that's about yer lot as far as comments from me are concerned, on any subject, really.

Omnis are something I have been intrigued with and the Doc, indirectly, has inspired me to explore them and this 1960s/70s design allows me to combine the Met shape, folded quarter-wave, air mass loaded lines and the omni concept in one speaker. For me there's nothing not to like.

Ideally, what would please me no end on this thread, would be some discussion of omnis, versus (as DSJR calls them) "point and squirt" speakers, without sarky interjections, let's see some new kinds of discussion. The coming together of HFS and Audio Talk has massive potential to benefit both places.
Here's hoping for some great times in 2017.
See y'all around Owston time.
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#5 Re: Up-Firing Met in Larsen Pyramid Stylee

Post by pre65 »

More power to your elbow Steve.

Looking forward to regular updates on your progress.

And, a sincere wish for you to have a happy and untroubled new year.
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#6 Re: Up-Firing Met in Larsen Pyramid Stylee

Post by Dave the bass »

OOOoooo! Omni's, now there's a brave fella, go for it Steve.

I hope they sound better than the only pair I've heard so far! At an Audiojumble a few years back there was a pair of Lowthers mounted so they fired upwards into a sort of semi circular diffusion/guide piece. They sounded ermmmm....... 'not right' TBH I have to say. I'll have a look later and see if I can find some info on what they were maybe.

But I don't want to put you off, I hope you understand!
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#7 Re: Up-Firing Met in Larsen Pyramid Stylee

Post by Cressy Snr »

Something I have to do Dave :wink:

The Doc's NVA cube series I think work on the semi-omni principle, where the bass/mids fire upwards but the tweeters fire forwards, which common sense says would help soundstaging enormously by giving some direct localising cues, which a full omni like the Larsen would have fallen down on. Car audio systems with door speakers and dashboard up firing tweeters are another example.
Also with the Doc mods to the drivers in his own Cubes, resulting in a simple cap crossover, we have a first order filter, which puts the HF 90 degrees out of phase with the bass mids. So if the tweeters are firing forwards when they are already 90degrees out of phase, it only takes a simple reversal to put them back in phase, again, helping the imaging whilst keeping the crossover out of the way of the music.

If I'm talking out of my arse, no doubt he'll be along later to tell it like it is, which is exactly what I want.
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#8 Re: Up-Firing Met in Larsen Pyramid Stylee

Post by shane »

I haven't heard any omnis since selling the odd pair of Sonabs back in the 70s, but I always liked the idea and definitely remember liking the result. Open, airy and spacious, but not much in the way of defined imaging. Effective on the likes of Klaus Schulz, Neu and so on. Following this with interest!
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#9 Re: Up-Firing Met in Larsen Pyramid Stylee

Post by cressy »

I had some canon s30 omnis years ago that made a nice noise, never found any floorstanding s35s though.
Mushroom shaped things that looked really quirky. They fired downwards and were really nice in the old house I used to have with a small living room.
Were too small for this house though, the living/dining room ( all open plan) is at least 3 times the size so they were lost in it.
Cant remember what happened to them
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#10 Re: Up-Firing Met in Larsen Pyramid Stylee

Post by IslandPink »

Cressy Snr wrote: full omni like the Larsen
Haven't seen those, have you got a link ?
Cressy Snr wrote: Also with the Doc mods to the drivers in his own Cubes, resulting in a simple cap crossover, we have a first order filter, which puts the HF 90 degrees out of phase with the bass mids. So if the tweeters are firing forwards when they are already 90degrees out of phase, it only takes a simple reversal to put them back in phase, again, helping the imaging ....
Not sure of the logic there, it's ultimately down to how far away the woofer and tweeter are from your ears, specifically the difference in distance - and how many wavelengths or half wavelengths that difference equates to at eg. 2.5kHz, or wherever the crossover is chosen. Then there's the problem of whether the woofer's phase has drifted due to cone breakup as it goes into the kHz range. At the end of the day it may come down to simple trial & error, try it both ways round on the tweeter connection.
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#11 Re: Up-Firing Met in Larsen Pyramid Stylee

Post by Toppsy »

Steve,
These should be an interesting challenge and I hope they work well. Look forward to hearing them sometime.

Scott and I did a couple of sorta Omni-directional speakers as MLTL's in 2009 with forward firing and upward firing Mark Audio FR drivers. The results were quite interesting but great care in protecting the upward firing driver was essential.

The Edlingham MLTL's were for the Mark Audio Alpair10 drivers and the thread is here http://www.audio-talk.co.uk/phpBB3/view ... f=4&t=1949

The Chillingham MLTL's for the Mark Audio CHR70 is here http://www.audio-talk.co.uk/phpBB3/view ... f=4&t=1742

Not what you are designing I appreciate but might give you some inspiration.
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#12 Re: Up-Firing Met in Larsen Pyramid Stylee

Post by Cressy Snr »

IslandPink wrote:
Cressy Snr wrote: full omni like the Larsen
Haven't seen those, have you got a link ?
Cressy Snr wrote: Also with the Doc mods to the drivers in his own Cubes, resulting in a simple cap crossover, we have a first order filter, which puts the HF 90 degrees out of phase with the bass mids. So if the tweeters are firing forwards when they are already 90degrees out of phase, it only takes a simple reversal to put them back in phase, again, helping the imaging ....
Not sure of the logic there, it's ultimately down to how far away the woofer and tweeter are from your ears, specifically the difference in distance - and how many wavelengths or half wavelengths that difference equates to at eg. 2.5kHz, or wherever the crossover is chosen. Then there's the problem of whether the woofer's phase has drifted due to cone breakup as it goes into the kHz range. At the end of the day it may come down to simple trial & error, try it both ways round on the tweeter connection.
I was only talking about electrical phase in the crossover rather than acoustic phase, which with an omni could be a king size can of worms, but we'll cross that bridge....etc.
I can only find images of the Larsen Pyramid; no articles that I can see.
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#13 Re: Up-Firing Met in Larsen Pyramid Stylee

Post by Cressy Snr »

Colin.
Thanks for the links.
I'd forgotten about those.
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#14 Re: Up-Firing Met in Larsen Pyramid Stylee

Post by pre65 »

I think it may be Larson, not Larsen if that helps your search.
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#15 Re: Up-Firing Met in Larsen Pyramid Stylee

Post by Dave the bass »

Sorry Steve, I can't find any info on the upwards firing Lowther speakers I heard at the AudioJumble.

The sound was 'odd' I seem to remember though, as though there were holes in the response. They sounded phsically wide but some of the info was missing, it was hard to describe. They weren't being demo'd in a great place, IIRC it was an entrance foyer or something with a lot of people walking through the listening area! Bit of 'mare I'd imagine. Maybe our-Thomas remembers them too, I dunno if the Kent Massiff went as a duo that day, it was a long time ago.
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