Please help me to chose the right enclosures for these 12" speakers:

Please help me to chose the right enclosures for these 12" speakers:


Impedance: 8 Ohm
Minimum frequency response: 31Hz
Reproduction frequency response : Fo - 17K
SPL: 94,587db/W(m)
Rated Input: 30W
Music Power: 45W
Equivalent diagram radius: 135mm
Equivalent mass: 29,786g
Magnet wight: 1350g
Net Weight: 5050g
Fs: 31.24Hz
Re: 7.2 Ohm
Mms: 36.331g
BL: 9.810TM
QTS: 0.495
QMS: 6.907
QES: 0.534
Vas: 259.741
Xmax: 1.0mm
no: 1.435%

Thank you!
 
What are the drivers - something locally crafted?

Try these:

mh-audio.nl - Calculations

1) sealed enclosure calculator
2) calculate maximum sound pressure level

The second one is a little buggy - you have to re-enter the diameter every time you change anything.

These show that a 'standard' sealed box (Qtc 0.7) of 250 litres would have a -3dB point of 44Hz, which is pretty good. The 1mm Xmax means a pair of drivers will produce 96dB at 45Hz (implying they would hit Xmax with about 2 watts of power).

Porting would require a ~500 litre box for a flat response. A horn would be bigger. I'd only consider that if I was using a low powered valve amp, had a lot of space, and knew I'd never have to move the speakers.

An 'undersized' sealed enclosure, 80-100 litres, would:

-be more portable
-give a Qtc of about 1.0 (not too bad)
-raise the -3dB point to 50Hz (not too bad)
-increase the power handling / reduce excursion

...this might allow you to feed them 4 or 5 watts before reaching Xmax.

That's how I'd do. I'd make boxes that were a little off being 50cm cubes, and then as 'stands' I'd build a pair of powered subs that were also a little off being 50cm cubes :)
 

freddi

Member
Paid Member
2005-08-16 4:21 pm
look for the Karlsonator or mini-Karlsonator thread - post your parameters Akabak-friendly as follows and ask xrk971 if your driver will perform acceptably in the 12 inch Karlsonator

assign a reasonable value for Le - its probably around half a milliHenry

I think it would work in the stock original Karlson but the Karlsonator 12 is somewhat smaller and tuned about a half octave lower than "K15"

Def_Driver 'Snake69Fast" |Notes: 12 inch fullrange SPL: 94,587db 30 watt 1mm xmax Qts 0.495
SD=572.56cm2
fs=31.24
Mms=36.331g
Qms=6.907
Qes=0.534
Re=7.2
BL: 9.810TM
Le=???mH
Vas: 259.741

Karlsonator12 plan
https://lh6.googleusercontent.com/-.../AAAAAAAABik/txissf4J4PI/s800/Karlsonator.png
 
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Snake are these Aucharm p1210s ?
I was looking at the specs the other month but opted for the smaller p810 they work fine in 70 litre stuffed sealed box with qtc 1 similar to what hollow boy suggested for your drivers, I however have them in a smallish room with thick walls so they are getting a fair bit of room gain.
If you need a lot of bass or have a large room then Freddis Karlson/Karlsonator idea may be a worth pursuing
 
look for the Karlsonator or mini-Karlsonator thread - post your parameters Akabak-friendly as follows and ask xrk971 if your driver will perform acceptably in the 12 inch Karlsonator

assign a reasonable value for Le - its probably around half a milliHenry

I think it would work in the stock original Karlson but the Karlsonator 12 is somewhat smaller and tuned about a half octave lower than "K15"

Def_Driver 'Snake69Fast" |Notes: 12 inch fullrange SPL: 94,587db 30 watt 1mm xmax Qts 0.495
SD=572.56cm2
fs=31.24
Mms=36.331g
Qms=6.907
Qes=0.534
Re=7.2
BL: 9.810TM
Le=???mH
Vas: 259.741

Karlsonator12 plan
https://lh6.googleusercontent.com/-.../AAAAAAAABik/txissf4J4PI/s800/Karlsonator.png

I've just posted the same question in the Karlson Thread. Thank you for the idea.
 
What are the drivers - something locally crafted?

Try these:

mh-audio.nl - Calculations

1) sealed enclosure calculator
2) calculate maximum sound pressure level

The second one is a little buggy - you have to re-enter the diameter every time you change anything.

These show that a 'standard' sealed box (Qtc 0.7) of 250 litres would have a -3dB point of 44Hz, which is pretty good. The 1mm Xmax means a pair of drivers will produce 96dB at 45Hz (implying they would hit Xmax with about 2 watts of power).

Porting would require a ~500 litre box for a flat response. A horn would be bigger. I'd only consider that if I was using a low powered valve amp, had a lot of space, and knew I'd never have to move the speakers.

An 'undersized' sealed enclosure, 80-100 litres, would:

-be more portable
-give a Qtc of about 1.0 (not too bad)
-raise the -3dB point to 50Hz (not too bad)
-increase the power handling / reduce excursion

...this might allow you to feed them 4 or 5 watts before reaching Xmax.

That's how I'd do. I'd make boxes that were a little off being 50cm cubes, and then as 'stands' I'd build a pair of powered subs that were also a little off being 50cm cubes :)

I have enough space in a big attic. So I am looking for the best sound no mater what size, weight etc. 500l sealed? Do you have some best ratio in mind for that? (length, width, height)

Thank you!
 
I like the old classic BR alignments for vintage spec drivers, so ~180.38 L tuned to actual Fs or ~44.65 cm^2 [~7.54 cm diameter] x 1.8" baffle thickness based on 31 Hz. Damp to 'taste'.

GM

Did I understand correct? A front square baffle with l=44.65 cm with a hole of 7.54 cm diameter for a 180.38 L BR enclosure? I am not sure as I never built a BR enclosure before.

Thank you!
 
Did I understand correct? A front square baffle with l=44.65 cm with a hole of 7.54 cm diameter for a 180.38 L BR enclosure? I am not sure as I never built a BR enclosure before.

Thank you!

Well, I would use a golden or acoustic ratio rectangular baffle to average out its eigenmodes. Yes, just a simple hole if the baffle is ~18 mm thick. The driver can't handle much power at low distortion, so a simple reflex vent is fine.

You're welcome!

GM
 
I was guesstimating 500 litre for ported (vented). If GM says otherwise, ignore me and follow his advice.

Well, you can make a nice flat sim down to below a grand piano's tuning [27.5 Hz], but power handling is so wimpy and the room will likely boost it enough to maybe muck up the > 42 Hz BW where most music is, so as much as I like the big box sound I would make 500 L sealed and hope the room will boost its LF enough to get decent performance out of it and limit vented to its classic alignment, which a stereo pair should handle most recordings to near piano bar levels at 1 m down to 32 Hz.

Not too shabby for a 'FR' driver IF it can cleanly handle Hammond organs, kick drums at 30 W.

I'm no fan of Karlsons for 'FR' apps, but it will control the driver much better than a BR through the mid-bass, so maybe the better choice overall depending on the driver's 'integrity' and your musical preferences.

GM
 
Do you want use for fullrange?

I would suggest:
Forgot all parameters.
Never a big box - as 250 L or 500 L - these are rumbling roaring crates. You would sacrifice much much cleannes in deeps, mids, highs for some dB sub - and these too would not play clean. TSP-Theory is too simple, does not regard a lot, as resonating planks or not rigid casing or not-filtering of higher frequencies or modulation to driver or...

My suggest: A cube, ca. 40 x 40 x 50 deep, stands. Good stiffed - all 8 - 10 cm the opposite planks! - good filled.
Driver decoupled AND clamped!

(To) avoid much much un-cleanness.-)
 
For the sealed one what else should I consider?

Since you said earlier
"I am looking for the best sound no mater what size, weight etc."

This means you are free to apply all the usual tips for making a speaker good - use thick walls, oversized, solid construction, lots and lots of bracing.

Some links of construction advice:

DIY Audio Speaker Box Building Guide
Speaker cab construction plans - construction tips

- I prefer the latter's recommendation of good plywood rather than MDF (lighter and nicer to work with)

Cabinet-damping
chamfering driver holes

These 'wide baffles' would be a good shape to copy for your front panel. Wide with big round edges = ideal.

Infinite-baffle

All of this is valid whether or not you port your box.

There is nothing stopping you from trying both. You could cut a port, following GM's advice, then seal it up, or partially seal it (stuff it with wool), and see which option you prefer.

If so: put the port low on the rear of the cabinet (out of sight).
 
I have enough space in a big attic. So I am looking for the best sound no mater what size, weight etc. 500l sealed? Do you have some best ratio in mind for that? (length, width, height)

Thank you!

Hmm, cumbb asks a good question, so what app is this driver for? I've been assuming 'full-range'.

A high aspect ratio tower/column [MLTL] or even a huge pipe horn [BIB] tuned up to an octave below Fs is an option depending on the app and if size/material cost isn't a major factor.

Also, for my records, what brand/model?

GM
 

freddi

Member
Paid Member
2005-08-16 4:21 pm
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