Kevlar speaker cones

[Mark Hammer]

I've suggested this in past, but never gone the full distance myself (though now I'm curious to try).  And the suggestion is this: combine a small subwoofer system with modest-sized (and separately powered) speakers for the non-bass content.

Just about everyone has, or can easily get, some cast-off 2.1 or other powered subwoofer that was part of an entry-level home-theatre or gaming sound system.  Generally, it will involve a 4" or similar-sized long-throw driver and some power-chip amp of 10+ watts, sitting in a ported cab that is the size of your average $50 practice amp.

If a person wants the deep bass from their amp, that will normally require larger diameter speakers, which, in turn, will require a noticeably larger cab.  But why not use a single 6", 8", or 10", in a cab that incorporates a built-in sub-woofer enclosure?  The preamp output gets split and fed to whatever powers the fuller-range speaker, and the sub-woofer power amp.  The fuller-range speaker - especially if it is <10" - will not likely have much useful output below 160-200hz, but that can be farmed out to the subwoofer.  Because the deep bass is essentially omni-directional, that provides some flexibility in terms of driver positioning, and the construction of any sub-enclosure or port within the larger cab.  It is possible there will be some phase-related issues between sub and full-range driver systems, but that should be fixable.

[tca]

...combine a small subwoofer system with modest-sized (and separately powered) speakers for the non-bass content.

That might work, specially for those who play with synths! You will have to make some kind of crossover network (passive or active). I'm not sure about the crossover freq. or simply use the natural freq. roll-off of the speakers to do the splitting.

The problem I find with small full-range speakers, apart from the short low end extension, is that they lack structural mechanical stability, that is, they mechanical vibrate with lower frequency input (bzz's and rrr's). That was one of the reasons for getting these Kevlar speakers.

The Kevlar has a lot more mids as GGBB point out, I think the kevlar is responsible for it, but it needs another cab for more testing.

[Mark Hammer]

If one uses some sort of active frequency-dividing to keep the more troublesome frequencies out of the fuller-range speaker/s, perhaps that will cure their "misbehaviour" at the low end.

I read somewhere once that one of Jeff Beck's preferred recording arrangements during the 70's and at least part of the 80's, was to use a Princeton pushed to its limits for the mids and highs, and a Twin with the treble rolled off, for the low end.

What I suggested in terms of adding a subwoofer isn't exactly the same thing, but it does move more in that direction, making better use of a medium-sized speaker for its more "vocal" qualities, and another driver for the feel-it-in-your-chest aspects.

[tca]

^ I've done some experimentation with this Voigt tube (mass loaded - transmission line enclosure) to get more bass out of a small speaker (120Hz-12kHz).



Although it works nicely for regular/music audio it sucks with distortion when I plug my guitar amp, it only works with a clean guitar signal.

There is not much references on the subject but it seems that regular speakers reacts badly with a distorted signal but can reproduce an audio track with a distorted guitar. Works for reproduction but not for creation of music, very paradoxical.

[Fender3D]

...
There is not much references on the subject but it seems that regular speakers reacts badly with a distorted signal but can reproduce an audio track with a distorted guitar. Works for reproduction but not for creation of music, very paradoxical.

Do not forget that everything you've heard about "guitar sound" on records, since ever, includes irregular guitar speakers freq. response

[Mike Burgundy]

There is not much references on the subject but it seems that regular speakers reacts badly with a distorted signal but can reproduce an audio track with a distorted guitar. Works for reproduction but not for creation of music, very paradoxical.

weeelll, not quite. Consider this: a guitar string produces a note that is already rich in harmonics (more like a sawtooth than a sine) - distortion adds harmonics. *lots* of harmonics. A guitar speaker acts like a low-pass filter, hard-filtering everything above 4-7kHz depending on speaker. A full-range speaker doesn't filter out all that high frequency content and will try to remove the glazing from your teeth while a guitar speaker sounds fine.
A recording taken from that same guitar speaker already has the filter (ie THAT speaker) applied and so sounds fine through a full range system.
That said - you don't necessarily need a guitar speaker to get a good and/or distinctive sound, whatever works... as long as the results sound pleasing (or just as unpleasant as you want it to be)

Liking that speaker. Never heard of a voight-tube, gotta look that up.

[tca]

^ Sounds reasonable.  Nevertheless I've to test a full range speaker with a good bass extension. Something like the Visaton BG 20 - 8 Ohm: http://visaton.de/en/chassis_zubehoer/breitband/bg20_8.html

Rated power    40 W
Maximum power    70 W
Nominal impedance Z    8 Ohm
Frequency response    fu–18000 Hz
(fu: Lower cut-off frequency depending on cabinet)    .
Mean sound pressure level    92 dB (1 W/1 m)
Opening angle (-6 dB)    45°/4000 Hz
Excursion limit    +/−4 mm
Resonance frequency fs    38 Hz
Magnetic induction    1,2 T
Magnetic flux    380 µWb
Height of front pole-plate    4 mm
Voice coil diameter    25 mm
Height of winding    8 mm
Cutout diameter    184 mm
Net weight    1,3 kg
D.C. resistance Rdc    6,2 Ohm
Mechanical Q factor Qms    3,47
Electrical Q factor Qes    0,51
Total Q factor Qts    0,44
Equivalent volume Vas    110 l
Effective piston area Sd    214 cm²
Dynamically moved mass Mms    10 g
Force factor Bxl    6,1 Tm
Inductance of the voice coil L    0,8 mH

I do not have all the specs for the Kevlar speaker to play with a cab simulator.

Liking that speaker. Never heard of a voight-tube, gotta look that up.

Voigt no h

Search for "Voigt pipe"

P.S.
BTW here is the link for Visaton's Boxsim software: http://www.visaton.com/en/literature/software/downloads/

P.P.S.
Found the specs for the Skytronics speakers if someone would like to take a go:
http://www.discoworld.dk/shop/manuals/skytronic/thielesmall_902127.pdf

Kevlar: 902.420
Polypropylene:  902.208

[PRR]

At least this one has specs.

> Resonance frequency fs    38 Hz
> Total Q factor Qts    0,44

The basic alignment is a closed box with Q near 1. All others are variations.

fs/Qts = 38/0.44 = 86Hz resonance in box at Q=1. F3db is about 0.8 of that or 69Hz.

We don't even need to compute since that page shows a 30 l box tunes to 82Hz and Q=0.96, which is a fine alignment.

Not-bad for guitar.

(Vent-box and sub-resonant pipes can do better, but not an octave better.)

> Height of front pole-plate    4 mm
> Height of winding    8 mm

Cone excursion is 2mm peak. This is really all you can use when the cone also carries mid-range.... the half-inch (12mm) excursions on WOOFers will garble midrange (FM intermodulation, Doppler).

10 grams is very light for an Eight.

I think if you cut-out the wizzer-cone (so it doesn't try to go over 5KHz) it is a fine small guitar speaker.

I've spent too much time with a bigger-brother of that speaker (E-V 12TRX) to accept it as "hi-fi". But as I said, I did spend lots of time with such speakers, even at home. As a Twelve the treble is way too beamy, an Eight is not so bad.

[tca]

Not-bad for guitar.

Have to try it out. Thanks.

[tubegeek]

Voight-like pipes are my main stereo speakers.
Here's a page with an OLD pic:

http://home.earthlink.net/~jeremyepstein/tqwp.html

And the plan:

[tca]

Just rehouse the speaker, this time with some more thinking and calculations about the speaker enclosure.



Sounds really great!

Cheers.

[seedlings]

Great looking cab!  You guys know that square speakers and 3-D stamped dustcaps and flashy cone / basket materials and colors will come to guitar speakers at some point as they have to car audio.

As with every other part of the amps that shaped how we hear music, those vintage amps used the cheapest speakers available.  Usually the same speakers as the hifi guys used.  But, now that we're used to a particular voice for guitar speakers, the honorable gurus (meant in complete respect!) will resist the transition to modern.   Can't you see a day when every speaker is plastic with a neo mag... and just then some diy forum starts up making paper cones and paper formers, and alnico magnets!!! Botique all over again!

If your creation sounds like you want it, then it sounds good!

CHAD

[Gus]

seedlings

http://visualsound.net/the-hubcap-speaker-grill/

[seedlings]

seedlings

http://visualsound.net/the-hubcap-speaker-grill/

Forgot about that visual sound workhorse.  I stand corrected.  "Has come."

CHAD

[tca]

seedlings
http://visualsound.net/the-hubcap-speaker-grill/

Thanks! Hmmm, does it work the way it is described?

The Hubcap blocks those nasty ice-pick highs from the center of every guitar speaker and takes all the good full range sound and spreads it out almost 180 degrees.  Yes, it really does that.  Once you've tried it, you'll wonder how you ever lived without it.

Might hack something similar, just to see how it sounds.

P.S.
Never really thought about the relevance of omnidirectional guitar loudspeakers
- http://www.roger-russell.com/omni/omni.htm

If I recall correctly, there is a patent for that "Hubcap"?

P.P.S.
Fount it:
- https://www.google.com/patents/US20070025583

[tca]

seedlings

I guess it will, I'll try something like this:



or

[tca]

I wonder if that ^ is better than a typical beam blocker?