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Bang & Olufsen Book of Hi-Fi

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vikinger
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vikinger Posted: Fri, Oct 13 2017 9:03 AM

You may may need to click on the picture to see the book cover ( if it appears at all!) Posting a picture from an iPad does not seem to be straightforward!

I picked up this book for 99p after someone in another thread asked about the wisdom of paying $85 or $95 for one!

Published 1977.

Interesting comments from that time:

"It is pointless to have a loudspeaker with a bass response down to 20 Hz in a small room. The room itself is part of your listening apparatus and the cut-off frequency of the room is inversely proportional to its length. A room 17 ft long has acut off frequency of approximately 60 Hz; to hear sound at 30 Hz it must be 34 ft long." Elsewhere it says that the laws of diminishing returns applies to speaker design and there is little benefit in having more than a woofer, mid range and tweeter in a cabinet. What does that say about the BL90?

Graham

Guy
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Guy replied on Fri, Oct 13 2017 9:16 AM

vikinger:

... there is little benefit in having more than a woofer, mid range and tweeter in a cabinet. What does that say about the BL90?

It says that some people are prepared to pay a lot of money for a little benefit! Smile

(Photo not working for me, BTW) It is now!

 

vikinger
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vikinger replied on Fri, Oct 13 2017 9:43 AM

Guy:

vikinger:

... there is little benefit in having more than a woofer, mid range and tweeter in a cabinet. What does that say about the BL90?

It says that some people are prepared to pay a lot of money for a little benefit! Smile

(Photo not working for me, BTW)

Finally added the pic via an iMac/ Firefox edit.

Unable to remove the previous blank post (or edit it) for some reason.

The book is quite interesting (I think you have a bargain priced one too Guy?) ,,,, of course there is a lot of emphasis on record decks/ stylus, and tape recording, of much less interest to present day listeners.

Graham

Millemissen
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Guy:

vikinger:

... there is little benefit in having more than a woofer, mid range and tweeter in a cabinet. What does that say about the BL90?

It says that some people are prepared to pay a lot of money for a little benefit! Smile

(Photo not working for me, BTW) It is now!

It says that the speakers/amps technology has evolved quite a lot since then - the use of DSP amongst one of the things, that weren't used back then for speaker/room relations 

And besides, hardly anyone with a smallish room will want/buy the BL90'es.

MM

There is a tv - and there is a BV.

Guy
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Guy replied on Fri, Oct 13 2017 10:49 AM

Millemissen:

Guy:

vikinger:

... there is little benefit in having more than a woofer, mid range and tweeter in a cabinet. What does that say about the BL90?

It says that some people are prepared to pay a lot of money for a little benefit! Smile

(Photo not working for me, BTW) It is now!

It says that the speakers/amps technology has evolved quite a lot since then - the use of DSP amongst one of the things, that weren't used back then for speaker/room relations 

And besides, hardly anyone with a smallish room will want/buy the BL90'es.

MM

I agree.  But with the inclusion of the 'a' my statement is still valid!  (As in 'a little benefit', rather than 'little benefit')

 

Millemissen
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'Two small benefits' of multiple drivers (in the BL90'es):

Beamforming and Beamdirection.

MM

There is a tv - and there is a BV.

Guy
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Guy replied on Fri, Oct 13 2017 11:02 AM

 

Millemissen:

'Two small benefits' of multiple drivers (in the BL90'es):

Beamforming and Beamdirection.

MM

Oh good - we're in violent agreement! Wink

vikinger
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vikinger replied on Fri, Oct 13 2017 1:09 PM

vikinger:
"It is pointless to have a loudspeaker with a bass response down to 20 Hz in a small room. The room itself is part of your listening apparatus and the cut-off frequency of the room is inversely proportional to its length. A room 17 ft long has acut off frequency of approximately 60 Hz; to hear sound at 30 Hz it must be 34 ft long."

Does this imply, for example, that for rooms less than 17ft square, that the BL5 and larger BL's would have little or no advantage over, say, a BL9? Does it also imply that, except for creating a surround sound effect, there is little point adding more speakers to an adequate Beovision?

Graham

smuehli
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smuehli replied on Fri, Oct 13 2017 1:48 PM

Small Room = BL 3

Medium BL8000

Large BL 50

Hall BL 90 ;-)

Arena  = 2 pairs of BL 90 ;-)

smuehli
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smuehli replied on Fri, Oct 13 2017 1:48 PM

Small Room = BL 3

Medium BL8000

Large BL 50

Hall BL 90 ;-)

Arena  = 2 pairs of BL 90 ;-)

smuehli
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smuehli replied on Fri, Oct 13 2017 1:48 PM

Small Room = BL 3

Medium BL8000

Large BL 50

Hall BL 90 ;-)

Arena  = 2 pairs of BL 90 ;-)

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