Efficient Bookshelf?

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1) How large is too large?
2) What kind of material do you listen to- do you need extremely low bass?
3) Do you listen at a high SPL?
4) What kind of amp will you use- solid state, or tube? Specifically, is it OK for 4 ohm loads?

These are important questions for coming up with a good project. My bookshelf might be larger than your bookshelf, you know?

Just guessing, but I think that something on the large side with a paper woofer is what's going to do it for you. I'll look around a bit if you don't mind answering my questions.
 
frugal-phile™
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Whit said:
1) I'd like them to be 14hx9wx13d or smaller if possible.

2) I mainly listen to jazz and classical so I don't need extremely low bass.

3) No, I like around 70-75db.

4) It will be a solid state class-D amp. 4 ohm loads are ok.

Fonkens. 91-92 dB, 14 x 8 5/8 x 11 3/4.

fonken-v1-map-tn.gif


1st entry on the Fostex box-plan library page

http://www.planet10-hifi.com/boxes-fostex.html

I'm predudiced but think they really are stunning. I listen mostly to jazz with classical taking a big up-tick recently. These seem to work well with Class D amps.

dave
 
I still haven't purchased a small full-range driver to see what that's all about, although a lot of people like them. Still, I'm not sold on the idea.

According to models based on excursion, I have a fairly good idea of when my present speakers ought to start sounding horrible. Sure enough, if I feed them some loud bass they do start to freak out as predicted. With a small driver with low Xmax, I can't help but think that without some major horn loading there would be a major limitation in dynamics and bass. Give them bass bins and I might be on board.

I do agree with the part about Class-D amps, though. This kind of driver has often been said to work best with tube amps. Tube amps have a higher output impedance than solid state, something they share in common with Class-D.

With and classical, I kind of like the shallow roll-off of a sealed enclosure. Sure I'm not getting the deep notes, but the way the response tapers off sort of leaves them to my imagination and doesn't sound as unnatural as a ported box that's overdoes the bass. Extended bass shelf tunings sound nice to my ears.

I don't know of any good projects right now, but I'll keep my eyes out.
 
frugal-phile™
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joe carrow said:
I still haven't purchased a small full-range driver to see what that's all about, although a lot of people like them. Still, I'm not sold on the idea.


You need to hear a set of these then :)

With and classical, I kind of like the shallow roll-off of a sealed enclosure. Sure I'm not getting the deep notes, but the way the response tapers off sort of leaves them to my imagination and doesn't sound as unnatural as a ported box that's overdoes the bass.

The Fonken is designed to be more like an aperiodic box than a ported box. The bass they do produce (est 65-70 Hz) is well defined and nice. I've not been able to drive them over the edge with any of the amps i have... even when used in HT with mains set to large.

dave
 
frugal-phile™
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You would get the general idea. The rough edges on the drivers get smoothed over with driver mods. You'd have to shrink your box a bit -- but these MDF boxes really need some serious bracing anyway.

These ones?

http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=302-710

If it were a tiny bit taller it could be made into a foldeed diyAudio FR Ref ML-TL... it should be big enuff to squeeze a Fonken-ish design into.

dave
 
I'm always intrigued by people that listen to classical and follow up with "I don't need bass extension"

Maybe it's just my collection, but classical is the most demanding (and difficult) music I have. Haven't met a single driver speaker that didn't leave me wondering where the rest of the music went. Well, not one sized decently. ;)

C
 
CJD, such drivers do exist. However many don't go as deep as we want. This may explain why such examples still provide plenty of enjoyment. http://hyperphysics.phy-astr.gsu.edu/hbase/sound/subton.html#c2

I agree that clasical / orchestral music places more requirements than rock or jazz. A bass guitar that rarely plays the bottom octave and a bass drum compared to double basses, tympanies and and the like. More often used by more instruments.

Latin American somewhere in between. Then some of the modern RNB has heavy requirements, if you want it.

Geoff.
 
indoubt said:
Humble homemade hifi has a bookshelf which is using the 93db Efficient PHL 1280. The efficiency will be lower because of the crossover filter but will still be above most bookshelfs and will probably give more bass than the low excursion single unit versions

An externally hosted image should be here but it was not working when we last tested it.


http://www.humblehomemadehifi.com/Phlea.html

around 90dB/W, recommended box, 12L tuned to 55Hz.

:)/sreten.
 
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