Burhoe Inspired Room Flooder

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SteveTheShadow
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Re: Burhoe Inspired Room Flooder

Unread post by SteveTheShadow »

At the moment, these speakers are a lash-up; built from bits of my old Flatback speakers, plus some MDF side cheeks. However, though they use the same drivers, the sound is very different, due to the difference in the way that these speakers interact with the room.
The ratio between the direct and the reflected sound has been tilted (literally) slightly more towards the direct and I think I have hit the golden ratio; in my almost 10ft high ceilinged room at least.

The good localisation cues provided by the Allison/Dunn derived approach of the forward-firing tweeter were something I didn't want to lose, with this redesign, but at the same time, the vertical firing main drive unit is heavily dependant on the proximity of a rear room boundary in order to get 'presence' and focus to the soundfield; fine in average sized rooms, as all us semi-omni users know, but in larger rooms, the rear wall proximity output ends up being significantly weakened by the lack of any other nearby room walls to the left, right and (nine times out of ten) above, because of high ceilings. The result of this is that the speakers can, all too easily become "lost" in the room, and all you end up with then, is the thing puffing and wheezing away to itself and simply not communicating.

The frustration I have with this, b'stard of a large room problem has prompted me to look seriously at the Burhoe flooder, but incorporating the Allison/Dunn forward tweeter approach to the mix.

The conventional room flooder has both the tweeter and the main driver firing up on the diagonal as in various Direct Acoustics (Burhoe's current firm) Shahinian and Larsen models.

All I have done is to combine the two methods into one speaker design. They work very well in my own room, better than the straight up firer, and they are going to a much larger room than mine tomorrow (Friday) to see how they perform.

The way they work there, will tell me if the design is worth scaling up for bigger rooms or not.

It's been a long old road with semi omnis, the journey down which for me, has been spoiled somewhat by a great deal of unnecessary unpleasantness. However the support of the Doc, and also reading Stu's adventures, and the undeniable excellence of musical presentation offered by semi-omnis, tells me I'm on the right lines.

That a ruddy speaker design could have caused such a frack arse, saddens me greatly. But though I was a few months ago, very tempted to just abandon the whole thing for the sake of maintaining good relations, and (if the truth be told) my own mental health, I'm glad I stuck with it.

What I'm hoping the visit to Hull will show is that although both the flooder and the Allison/Dunn approach to semi-omnis is equally valid, there is another way: a way that combines the two of them into one "super semi-omni" - one that improves on both.

We'll soon find out one way or the other.
Last edited by SteveTheShadow on Thu Feb 22, 2018 2:28 pm, edited 1 time in total.
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SteveTheShadow
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Re: Burhoe Inspired Room Flooder

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Epicure Model 20 from the early 80s, is very similar to what I came up with, and is an older Burhoe type design.

Image

There's nothing new in what I'm doing. The idea is there in this pic, but I only have the tweeter in the front position and the front section of my baffle, slopes upward towards the listening seat.
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karatestu
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Re: Burhoe Inspired Room Flooder

Unread post by karatestu »

Well Steve, all credit to you for coming up with this idea. :clap: I have played with upfiring tweeters but not with the mid angled forward. You are an evil man ;) - just when I thought I had finished playing around with my main speakers and you drop this bomb shell. I might try using this approach too as long as doing so does not upset you.

Is this your first speaker with doped driver and no low pass filter ?

Oh and you know, as you have said to me in the past you need to start building some proper speakers -point & squirt with an array of tiny drivers, a cabinet stuffed to the brim and a crossover stuffed to the hilt with music destroying components.

Stu :guiness;
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Dr Bunsen Honeydew
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Re: Burhoe Inspired Room Flooder

Unread post by Dr Bunsen Honeydew »

Enough already, or we will never see anything finished. You need a pair of these, you are like a shaggy dog hanging out a car window- ooo look at that, no that is better, perhaps if - bright eyed tongue hanging out.

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Re: Burhoe Inspired Room Flooder

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karatestu wrote: Thu Feb 22, 2018 4:58 pm Well Steve, all credit to you for coming up with this idea. :clap: I have played with upfiring tweeters but not with the mid angled forward. You are an evil man ;) - just when I thought I had finished playing around with my main speakers and you drop this bomb shell. I might try using this approach too as long as doing so does not upset you.
No problem Stu. The more people try these kinds of ideas the better. Better to do this sort of thing than to be p*ssing about, like a deluded fool, with stupid fuses, racks and magic crystals.
Is this your first speaker with doped driver and no low pass filter ?
Been doing simple one cap crossovers for years and years. The doping however is a new thing.
I did use a black tack ring at the junction of the voice coil and dustcap, on my last pair of speakers, now owned by someone else. The effect of that was to pique my interest in driver doping.
Oh and you know, as you have said to me in the past you need to start building some proper speakers -point & squirt with an array of tiny drivers, a cabinet stuffed to the brim and a crossover stuffed to the hilt with music destroying components.
No danger of me building anything like that......whatsoever! :lol
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Re: Burhoe Inspired Room Flooder

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Dr Bunsen Honeydew wrote: Thu Feb 22, 2018 5:19 pm Enough already, or we will never see anything finished. You need a pair of these, you are like a shaggy dog hanging out a car window- ooo look at that, no that is better, perhaps if - bright eyed tongue hanging out.

Image
:lol: :lol: :lol: woof woof

I can't help it doc, honest. I have already designed it in my head :grin: I have been compared to a dog before - one with two dicks :whistle:

I promise I will get something completely finished one of these days. :roll: What am I going to do then ? Some one will probably come up with the ridiculous idea of listening to some music. :hand:

Sorry Steve.
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Re: Burhoe Inspired Room Flooder

Unread post by Dr Bunsen Honeydew »

Finish something else, or improve it. At the moment you getting stuck in Limbo.

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Re: Burhoe Inspired Room Flooder

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The speakers were very successful during their visit to Hull last Friday and below is a nice endorsement from one of the guys there:
The speakers were a surprise for me. Completely different sound scape to the previous omnis. Just complete music, top to bottom. The pairing of amp and speakers did seem perfect, and although there was no image or stage the instrument separation was immaculate.
Now then.. :)
The image and stage question is a bit vexing with omnis, and it depends on the level of importance you give it personally as we all know. But the imaging question can put people off them, no matter how good a well designed omni sounds in all other areas.

I was searching Saturday morning using the key words "omnidirectional" and "imaging" and came across Siegfried Linkwitz's site. Plenty of great stuff on there about both open baffles and omni speakers, the omnis in question being the "Pluto".... a strange looking thing made out of a pipe, with an up-firing bass/mid with a little arm on the top to hold the forward-firing tweeter.

His explanation of the working of the Pluto was intriguing, seemed entirely logical, fitted with my own way of thinking about speakers, and looking at my speakers and the Pluto I decided they had quite a lot in common, though they look entirely different. So I decided to put my speakers about 18" out into in the room, like he'd done with the Pluto, just to see what would happen.
Image

Firing up "Summer Wind" from Frank Sinatra's 1967 "Strangers in the Night" album, the sound that erupted into the room was quite remarkable. Frank dead centre, the correct height for a grown man, with the orchestra arranged in a wide arc behind and to the sides. Close your eyes and convincing facsimilies of Frank himself and Billy May's band were paying a visit to your living room.

Dean Martin, Matt Monro, Bert Kaempfert, Petula Clark, Shirley Bassey, and their respective backing bands all paid me a visit too, during the time the speakers were out in the room. I deliberately chose these 1960s big band backed productions as they are exemplars of how to record stereo.

So these things actually do image, as Linkwitz's similar Plutos do, but.....as with the Cubes, you have to get the positioning right and the right position for imaging is incompatible with my domestic circumstances. So alas and alack, I will never be able to experience that thrill, except when the missus is out.

Nevertheless it's enough for me to know that they can do it and that I'm playing in the same ballpark as Linkwitz.

Wahey! :mrgreen:
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Re: Burhoe Inspired Room Flooder

Unread post by karatestu »

Steve, the baffle of my semi Omni's are 2 feet from the back wall and I love what they do. Also I have a window behind each speaker and the house walls are getting on for 2 feet in thickness. I always wondered what they would sound like right back to a solid wall but after your recent views of the room flooder out in to the room, I am not so eager to find out.

I don't have any problems with imaging and instruments are precisely located within the sound stage. I have messed about with toe in quite a bit and prefer them crossing over just in front of me.

Stu
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Re: Burhoe Inspired Room Flooder

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karatestu wrote: Mon Feb 26, 2018 2:08 pm Steve, the baffle of my semi Omni's are 2 feet from the back wall and I love what they do. Also I have a window behind each speaker and the house walls are getting on for 2 feet in thickness. I always wondered what they would sound like right back to a solid wall but after your recent views of the room flooder out in to the room, I am not so eager to find out.

I don't have any problems with imaging and instruments are precisely located within the sound stage. I have messed about with toe in quite a bit and prefer them crossing over just in front of me.

Stu
Unfortunately Stu, my domestic circumstances and tiny room (12ft x 12ft) simply does not allow out in the room placement, so I can't take advantage of their wonderful imaging properties. Also because of the close to wall bass alignment I designed in, the speakers lose most of the bottom end if pushed out in the room.

Nevertheless, omnis and semi-omnis, represent for me, the best way to make the speaker a part of the listening environment.
I'd much rather have the speaker adapt itself to the room as these types do, than have to adapt the room to the speaker, as the point and squirt brigade have to.
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Somebody’s stepping on my plastic sandals. Joe Jackson (1979)

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