Interesting read I found on Lossy Cabinet designs by Harbeth - Page 2 - diyAudio
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Old 11th November 2012, 12:39 AM   #11
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sorry Steve, I find "pointless waffle" about as mean spirited as Sreten's "clueless conjecture." What are you telling DIYers? Quit? Obey the Queen's dispatches? You have a party line for us to cleave to? Non parallel boxes are Satanic? What??
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Old 11th November 2012, 01:22 AM   #12
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Quote:
Originally Posted by system7 View Post
preferably in 0.618:1:1.618 golden ratio
Monitor 20 | 305 x 188 x 190mm | 0.99:1:1.605
Monitor 30.1 | 460 x 277 x 285mm | 0.97:1:1.614
Monitor 40.1 | 750 x 432 x 400mm | 0.926:1:1.736

P3ESR | 306 x 189 x 202 mm | 0.936:1:1.515
Compact 7ES-3 | 520 x 273 x 315mm | 0.867:1:1.651
Super HL5 | 638 x 322 x 300mm | 0.932:1:1.981
Monitor 30 | 460 x 277 x 285mm | 0.972:1:1.614

None of these are even close to a Classic Golden Ratio. 4 of 7 have one side that is close

dave
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Old 11th November 2012, 09:00 PM   #13
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Default My bad

Dave is correct, I got all snarky on Sreten and System 7, both of whom steadily contribute well founded information here. I should know as much, but do not. Sorry about that.
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Old 11th November 2012, 09:29 PM   #14
system7 is offline system7  United Kingdom
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No pointless waffle with me, anyway! Just get a bit fed up with 100 page epics that are unreadable.

The Golden Ratio (0.618:1:1.618), or Acoustic Ratio (0.8:1:1.25) cabinets are some sort of ideal IMO. This is the INTERNAL dimensions of course. But there are other considerations that Alan Shaw probably has. Like getting the woofer edges near the edge of the cabinet. Or getting a bit more bass out of a small box.

He certainly is quite willing to share his design ideas: Harbeth UK

This picture of a big M40.1 cabinet was educational. No fluff at all in the bass cavity. Midrange gets a different treatment.

Click the image to open in full size.

The second image is Joachim Gerhard's Sonics Anima which has a removable base plate. Made of Bamboo or something these days.
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File Type: jpg m40assembly-l.jpg (58.8 KB, 561 views)
File Type: jpg Sonics_Anima_Joachim_Gerhard_3.jpg (110.1 KB, 577 views)
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Old 18th November 2012, 11:24 AM   #15
system7 is offline system7  United Kingdom
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Whilst the forum is busy turning the question of how to fit a simple cabinet brace into another epic, me being a simple soul; I have been looking further into the famous Harbeth cabinets.
Harbeth Monitor 40.1

Recall Alan Shaw's analogy to a "Cracked Bell" not ringing. The Monitor 40.1 is notable for having almost NO boxiness to the sound. Not quite sure if the brace is glued to the sides here. It's a secret...

There IS some stuffing in the box though. Looser behind the woofer, I surmise. Quite honestly, Harbeth speakers are so good, so lovely, I suspect I would just buy them if I was a bit richer, and abandon diy altogether!
Attached Images
File Type: jpg Harbeth_Monitor_40.1_Front_Panel.JPG (38.8 KB, 549 views)
File Type: jpg Harbeth_Monitor_40.1_Battens.JPG (48.4 KB, 532 views)
File Type: jpg Harbeth_Monitor_40.1_Bracing.jpg (57.3 KB, 215 views)
File Type: jpg Harbeth_Monitor_40.1_stuffing.jpg (79.6 KB, 234 views)
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Well, there it is! Best regards from Steve in Portsmouth, UK.
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Old 18th November 2012, 11:56 AM   #16
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This BBC/Harbeth approach is good cabinet engineering. Their "philosophy" is backed by scientific data, and that's the only possibility to proof that your approach is right. Just claiming that your approach is right is not sufficient. Unfortunately, in HiFi this is the usual way.

But the most important quote from that thread is:

Quote:
Providing that the resonance, be it from the cone, cabinet or even recording - whatever the source - is x dBs below the fundamental, the BBC proved that it was completely inaudible. Once inaudible to trained listeners on all types of music/speech, that is the end of the matter. Inaudible to the trained listener is as good as the solution needs to be. It is neither necessary nor cost effective (nor good engineering) to continue pushing for a degree of theoretical excellence that nobody can appreciate but everyone must pay for.
Nothing to add.
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Old 18th November 2012, 12:00 PM   #17
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I wish I could be close to somewhere that carries Harbeth...never heard one yet
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Old 19th November 2012, 06:20 PM   #18
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I have never heard a Harbeth either but I have always been attracted to their design.

I have read that with modern speaker drivers a lossy cabinet is pointless. However, I argue that no matter what type of driver your are using, a sound wave is a sound wave. No matter the technology implemented the sound waves dont change their size.

I could be wrong in my theory of how to handle audio as so many argue that the strongest, heaviest cabinet is best. However, the bell analogy rings true(pun intended) and some claim it to be marketing "fairy dust".

However, I offer this. Is a Stradivarius the same as any other will made Violin? Why do expensive violins sound better than the cheap ones is it better build quality or the fact that special care is taken with the types of wood used and where it is used? The thickness of the wood in certain locations?

I view a speaker box to be just as much an instrument as a violin. With the drivers being the strings and the box to be the structure that the drivers ring through.

However, Audio is an imperfect science with so many different theories and ways of reproducing sound I dont see any one theory being correct and one wrong but all have their own merit.
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Old 19th November 2012, 07:15 PM   #19
tinitus is offline tinitus  Europe
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Quote:
Originally Posted by ORNJ View Post
I view a speaker box to be just as much an instrument as a violin. With the drivers being the strings and the box to be the structure that the drivers ring through.
better keep them seperated
music instruments and related gear is designed for making music

audio is designed to 'reproduce' music, and for making money


Quote:
Originally Posted by ORNJ View Post
However, Audio is an imperfect science .........
funny, I heard a scientist say that science is like fumbling and not knowing what to do or what happens

and when they know, its out of the scientists hands, and becomes engineering
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Old 19th November 2012, 08:37 PM   #20
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Quote:
Originally Posted by system7 View Post
The Monitor 40.1 is notable for having almost NO boxiness to the sound.
Hmmm...... Gonna have to disagree here. Having walked directly from an extended demo in the Magnapan room straight to the Harbeth room in Vegas, the coloration of the Harbeth was very noticeable. The coloration was of wood and paper, very distinct. Pleasant, organic, enjoyable, but strongly colored. I assume the woody flavor was from the box.

I like the big Harbeth, but you can hear the box - for better or worse.
Now that I know more about the construction, it's easy to understand why.
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