Cabinet design for 5" driver - guitar use

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I've a spare Jensen Mod 5-30, a 5" driver for guitar: Mod 5-30 | Jensen Loudspeakers Parameters below.

Given the small size, what would be the best approach for designing a cabinet? Would a multiple of Vas, sealed, extend the bass and give a 'normal' feel?

I've built a mini Karlsonator using foam core which extends the bass of a small driver. Would a similar approach be beneficial in the guitar-world?

General Characteristics for 8Ω
Nominal Overall Diameter 129 mm 5 in
Nominal Voice Coil Diameter 25 mm 0.98 in
Magnet Weight 380 g 13 oz
Overall Weight 0.98 kg 2.16 lbs
Flux Density 1.1 T

Thiele-Small Parameters for 8Ω
Voice Coil DC Resistance RE 6 Ω
Resonance Frequency ƒS 125 Hz
Mechanical Q Factor QMS 7.48
Electrical Q Factor QES 0.95
Total Q Factor QTS 0.84
Mechanical Moving Mass MMS 4.3 g
Mechanical Compliance CMS 378 µm/N
Force Factor BxL 4.59 Wb/m
Equivalent Acoustic Volume VAS 3.3 lt.
Maximum Linear Displacement XMAX ± 0.5 mm
Reference Efficiency nO 0.66 %
Diaphragm Area SD 78.5 cm2
Losses Electrical Resistance RES 47 Ω
Voice Coil Inductance @ 1kHz LE 0.19 mH
 
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PRR

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I've a spare Jensen Mod 5-30, a 5" driver for guitar:.... Given the small size, what would be the best approach for designing a cabinet? ....

A guitar speaker should be guitar size. 10" or 12". IMHO, a Five is a Ukelele speaker. Yes Godfrey and Tim got fame with ukeleles.

A "huge" box still won't cover the bottom octave of guitar. Infinite box will peak mildly at 125Hz and roll-off steep below 105Hz. This is only a half-octave shy of guitar low-note. And how often do you play the lowest 6 notes? Or mind if they sound on harmonics instead of gut-shaking fundamental?

However an infinite box is big. Infinite-enough might be 30L or a cubic foot. Alright, that could be a foot-stool or plant-stand. However a proper Ten in a cubic-foot would blow your Five out the door.

And your ear "knows" the sound is coming from a tea-saucer instead of a proper dinner-plate.

I *have* seen a Karlson as guitar amp; however I believe it was a failed hi-fi box from his father. It worked, but we were very young and not real savvy. I didn't think it did better than the same driver using the whole box plain.

A 2 cubic foot vent box could extend another half octave but I suspect it will slap on mega-deth bass lines.

A HORN would extend bass. But driver mouth and taper suggests 4 foot square mouth and 6 feet long. In a room that can be cheated. A half-scale Klipsch would do well to 800Hz but guitar harmonics would be lost in the bends.

Serious guitar wants a bigger driver. Bedroom playing is usually not about the lowest notes, and that MOD will do fine in bedroom work.

I have to go along with Sonce. 3-10 liters sealed. Try with and without stuffing.
 
Thanks all.

This is purely for home office noodling - learning new songs playing along with youtube etc etc. Not expecting any big (or deep) noises from it! Just if there was a way to make best use of what I've got to hand. Plus I've some spare pine / spruce hobby board and foam board sitting around so it would be a fun weekend activity to cobble something together.

Or could even look for a simple wooden box (from IKEA e.g.) to convert.

This site could be quite useful to quick and easy plans: Speaker Box Volume Calculator / Designer
 
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It´s a guitar speaker.
Make that a *killer* guitar speaker.

Just build a small box, from shoebox size (literally) to, say, the dimensions of a Fender Champ.
Open or closed back, both are valid but sound different,

You may experiment with removable back strips so you try fully_closed/half_closed/fully open.
You can even change from one to another when you get bored.

What amplifier will you use?
 
Any and all of AX84 projects are excellent sounding amplifiers :)

The presentation box walls are too thin for cabinet use, but hey, you already have it, so use it to find a perfect cabinet size and back opening (ignore buzzing and vibration he he :p ) and then build a real one :cool:

And you´ll only "lose" what you "invested" on it :cool:
 
The presentation box walls are too thin for cabinet use...
I once enjoyed a loudspeaker box made from a Styrofoam (white expanded polystyrene foam) cooler for a while. :)

It sounded surprisingly good - not "dead" like a good Hi-Fi speaker enclosure, but the Styrofoam has a lot of internal mechanical damping, so it doesn't ring or make unpleasant sounds. Almost neutral sounding, with a pleasant slight brightness.

Tubelab George has also mentioned using a Styrofoam cooler as a speaker enclosure, in a work situation where he wasn't allowed to bring stuff in...so he improvised with what he found.


-Gnobuddy
 
Qts 0.84 and Fs=125Hz ?

It is what it is. Whack it into a cheap open backed box and learn to love the midrange.

Have a look in the craft section at your local big-box store. Or the local OfficeWorks at storage boxes or document trays. Or sturdy shoe boxes.

Styrofoam; cardboard; MDF; thin ply; masonite; pine/bamboo. Any of them will work for bedroom noodling. You might need some reinforcement to hold the driver - automotive body panel clips work wonderfully.
 
Attached is what I have to hand today. The 'baffle' and rear are thinner plywood, which might be an issue but it's something to experiment with. Volume is ~6.7l.
 

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Better than perfect :)

Run a bead of glue along all joints and you´re done with the main cabinet.
Then experiment with backpanel sliding cover in/out until you find a sweet spot and you´re done.

To minimize vibration you *might* glue it again with a bead of glue along all mating joints but as an adjustable solution you may put a strip of any hard plastic, (think X-ray film, not soft plastic bag stuff) in one of the slots, so cover slides in under pressure.

FWIW *famous* Guitar amplifiers have been built using thin hardboard/masonite supporting two 12" speakers, go figure, such as Silvertone amps:

6x10" :eek:
An externally hosted image should be here but it was not working when we last tested it.


2 x 12":
An externally hosted image should be here but it was not working when we last tested it.


:cool:
 

PRR

Member
Joined 2003
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... I have an almost perfect test box - a 2 bottle presentation wine box with a slide-in lid....

Was the wine OK? At least at a behind-the-school-sock-hop level?

Then what's the question? This is NOT hi-fi. A guitar amp speaker really can be built nearly as light as an acoustic guitar. Even thin panels steer the sound.

The likely "fault" is rattles in the slides. Shim them with soft cardboard for trials. If you actually find some "optimum", hot-glue the slides.

I see where JMF is going. I sneer at one Five, but 8 Fives in a panel is a Real Speaker. Perhaps too much for office, even with tortured 6SN7 power.

{edit} Box says "cheesemongers". I don't recall sneaking cheese into a sock-hop.
 
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Attached is what I have to hand today.
A suggestion - try it positioned very close to your ears, say a foot or two in front of you, at head height.

With your ears in the speaker's near-field like this, the sound can be "big" even though the speaker isn't. The speaker is behaving half-way between headphones and a more conventionally positioned speaker.

As a bonus, the guitar can be reasonably loud at your ears, and still be fairly quiet ten or fifteen feet away.

This is the one tip you never read about in all those Internet discussions about bedroom electric guitar playing without annoying the rest of the family. I tried it on a whim, and was surprised at how well it worked.


-Gnobuddy
 
I don't recall sneaking cheese into a sock-hop.
What sock-hop? The kids are too overweight to hop these days, not to mention, traumatized at the thought of having to touch a dance partner. But revealing far too much on the 'Net is fine.

I helped chaperone some high-school dances some years ago. Most of the kids came in wearing sandals and sneakers, sat at tables, and texted and tweeted each other.

It is a strange new world!


-Gnobuddy
 
Remember not to centre it in the baffle (to minimise resonance).

Darn it - had already made the awful, not circular at all, hole... Probably not even in the center. I'd love to get better at woodworking to be able to make my own cabinets / boxes etc.

Was the wine OK?

It was a Christmas set of port and cheese - the port has yet to be opened...

Then what's the question? This is NOT hi-fi. A guitar amp speaker really can be built nearly as light as an acoustic guitar. Even thin panels steer the sound.

The likely "fault" is rattles in the slides. Shim them with soft cardboard for trials. If you actually find some "optimum", hot-glue the slides.

I see where JMF is going. I sneer at one Five, but 8 Fives in a panel is a Real Speaker. Perhaps too much for office, even with tortured 6SN7 power.

The sound is OK-ish clean - lots of top. But it's a kazoo when the gain is set higher. This would be an excellent example as to how much of an impact the speaker / cabinet can have on the overall tone.

Striking chords and sliding the back in and out is a fun excercise - I've yet to give it enough time to settle on a position, but initial findings:

- more closed = more bass
- more open = more top and 'honk'

A suggestion - try it positioned very close to your ears, say a foot or two in front of you, at head height.

With your ears in the speaker's near-field like this, the sound can be "big" even though the speaker isn't. The speaker is behaving half-way between headphones and a more conventionally positioned speaker.

As a bonus, the guitar can be reasonably loud at your ears, and still be fairly quiet ten or fifteen feet away.

This is the one tip you never read about in all those Internet discussions about bedroom electric guitar playing without annoying the rest of the family. I tried it on a whim, and was surprised at how well it worked.

Funnily enough this is exactly how I had it placed - on top of my amp head, which was on top of a mid-height bookcase.

Not bad for a cheap speaker and an upcycled wooden box.

Thanks for all your help and input. I'll report back once I've settled on a set-up.
 

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Tubelab George has also mentioned using a Styrofoam cooler as a speaker enclosure, in a work situation where he wasn't allowed to bring stuff in

They were made from Styrofoam bulk shipping cartons designed to hold 100 small pagers (remember those?) before the cell phone generation. We hacked out the individual pockets leaving us with a box about 3/4 cubic foot in size with nearly 1 inch thick walls of polystyrene foam quite a bit denser than the usual cooler. We stuffed those with a 6 inch or so speaker driver borrowed from the ceiling audio distribution system. We fed them with music from a DIY amp build based on the SWTPC plastic tiger (about 25 WPC). They sounded far better than expected. No pictures exist, cameras were a firing offense inside the plant.

But it's a kazoo when the gain is set higher.

If the ridged area at the edge of the cone can physically touch the wood at high volume levels, it could create a sound like a kazoo....been there, made that, fixed it with a wood file. It could also be the sliding back rattling. Remove it and test again.

I have one of those Jensen MOD 5's. It's not in a cabinet right now, but it was. The old cabinet looks to be about the same size as yours, but never had a back. It was used to test amp designs for the Hundred Buck Amp Challenge several years ago. It was a simple box made with sheetrock screws and scrap wood, and got tossed when I had to move everything I owned twice for a total of 1200 miles. I kept the speaker for a future project. Seen here eating about 25 watts of overdriven full metal racket. It sounded pretty good for lead guitar, but as expected you aren't going to get big bass, nor do you really want it if you play in the distortion region (sounds muddy).
 

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