The Metronome

Ive been pondering a BiB variant. Something along these lines, ~80" tall:

The Bibazoid.
229325218_964e6f3bd2_m.jpg
 
Could be very interesting. Greg? Dave? What sort of expansion rate / shape would we be looking at here? The standard BIB is basically conical, so I'd guess this would shift it toward being something on the lines of a hyperbolic? My only slight concern would be the transition from the front taper to the rear one might be a bit abrupt. I'm rotten at maths I'm afraid (i.e I'm thick) so I'm going to struggle figuring the dimensions to plug into the latest MathCad BLH Sections sheet as-is.
 
Hmmm, thinking about it some more Id probably change the depth from about 16" to 12". It may not be that different from regular BiB, but it eliminates parallel walls. If theres a transition discontinuity, the fold plane could bottom closer to the back wall to adjust such that mouth area is the same at each side.
 
Scott emailed the response curves and suggested mass loading the cabinets by means of base plate and a 2 inch port fed by a 3 inch long tube.

No hacking of the cabinets was needed. The mass loading ports fire downwards at the floor from behind the base arches and are invisible.

After much testing this afternoon culminating in me removing all the stuffing from the lines, They sound great.
They are even from top to bottom in room and with the help of the sub form a system that works beautifully together.
Coloration is low.
The lines are lined with carpet underlay so the additional stuffing was excessive and robbed the sound of life and dynamics .

I think we have a winner here guys.

I can only imagine what a taller line with a 6 or 8 inch FR driver would sound like, but that's for someone else to try.

Steve :)
 

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frugal-phile™
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Steve Cresswell said:
I think we have a winner here guys.

:^)

attached are plans... i had to shrink them a bit to get small enuff to attach so not as clear as i like. (i'll work up a better one for you to post Steve -- i'll also link to whereever you put it from my box-plan page -- i'll also generate the appropriate modeled responses.

dave
 

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Integrating Metronome w/ Sub

Steve, Dave, Scottmoose and others -- great work, very elegant. Steve, I'm wondering if you can say more about how you've managed the sub integration. Are you working with the natural bottom-end rolloff of the metronome?
Many thanks for a great thread.
John
 
Hi John,

The design just uses the natural roll off of the Fostex driver to integrate with the sub.

Because the bass response with the mass loading is flat down to around 50Hz then rolls away rapidly the Metronome is very easy to blend with the sub.

I have my sub set at 40Hz and placed in a corner and there are no problems at all.
The bass is well-balanced and extended with no boom.

The FE108 Sigma version of the Metronome (the smallest of a range of DIY designs coming soon) is a brilliant small room speaker and with its minimalist elegance would look great in a small contemporary environment.

Anyone building this speaker will not be disappointed.


Steve.
 
Hi Folks,

Just wondering if a BIB bass horn would sound good with a metronome fe108ez. Would it be too over powering? I just need an efficient sub-woofer that I could power with a T-amp. I would be running it as an active sub with the T-amp. Omnes Audio 2.1 amp. 2 T-amp 2024 modules, one for the mono sub with frequency 'thingy' (I know the german word for it!)

OR would a fe168ez achieve enough Bass to not need a sub?!?

I'm very attracted to the holographic sound you experience with these! Also the size! I've posted on the BIB thread too, as I want to do 2 projects, for fun and also so a friend of mine can also have a pair.

It's a pity that a pair of BIB's weren't in that great review with the son of frugals etc. Would have been good to compare the sound!

Cheers Stroop
 
Eeeeexxxxcellent!!!!

Hey Scott thanks a bunch!

Monacors should be good to get! I was looking at some scanspeak drivers...beautiful but not cheap. Scanspeak 18W 16545 K they are 17cm

* power handling (continuous/programme) = 100 W
* resonance frequency fs = 34 Hz
* impedance R = 14 Ohm
* sound pressure level SPL = 87 dB (2,83V; 1m)
* DC resistance Re = 10,6 Ohm
* voice coil inductance L = 0,4 mH
* effective piston radiating area Sd = 140 cm2
* effective mechanical mass incl. air load 14 g
* equivalent volume of compliance Vas = 53 l
* total Q factor Qts = 0,24 (Qms=4,9, Qes=0,25)
* maximum peak linear excursion vibration xlin = +/- 4,5 mm
* mounting diameter d = 157 mm
* overall diameter d = 177 mm

What should I look for in a driver...? By the way the Monacors do look very good!

Cheers Stroop
 
Depnds how big you want to go, the application it's used in, and what you most value in sound. For a moderate sized BIB cabinet, a nice mid Qt in the 0.3 - 0.45 range with an equally moderate Vas (up to ~ 35 litres) is about right. The Scan Speak's look like nice units, but I doubt they'd offer any more than the Monacor's in this application -maybe less. Pricier too & better to keep the extra cash in your own wallet for a while. Gives you more to spend on music.