Onken with Eminence drivers?

[Giaime]

Hello everybody!

This probably is my first post in the Loudspeakers area, so be nice I'm not an expert.

The question is: I'd like to make an Onken bass cabinet with Eminence or Ciare Speakers.

1) What parameters should I look for?

2) Is there an Eminence that you have tried or can point me at?

3) Is the popular xls "Onken Calculator" right? Or do I'm getting wrong results?

4) Some other European-available CHEAP drivers?

I calculated with the mentioned spreadsheet an Onken with a Eminence Beta12, it gave me a nice 230L cabinet tuned to about 30Hz, I made drawings for it but... what about the Xmax at 0.8mm????????? A friend of mine said that with 10W I will destroy the cone. Should I go for the Alpha 10 that has similar results when put in the mentioned xls?

Can someone help me? Thanks in advance!

[cotdt]

you want to use solar power.

[Giaime]

I already have used solar power to power a little tube amp.

Now I want Onkens!!!

Is this doable or the reply above should point me at the incredible difficulties I will find in trying to use an Eminence for an Onken cabinet???

Please be nice

[Ron E]

What do you think is different about an Onken vs. a vented box?

[Giaime]

I'm not an expert, but I heard Onken allignment helps with high efficiency woofers, to let them go down in the frequency range. Also I've read they have faster bass. I don't like bass reflex bass, for example, in fact now I'm using sealed boxes speakers.

Is this true or there's something I should know about Onkens?

[GM]

Greets!

There's nothing magical about the Onken, so in theory any driver suitable for a vented alignment will work, but the reality is that it needs specs that don't make the vents excessively long. FWIW, I use ~24" (~61 cm) long as the practical limit. Note that you can use fewer vents and/or as little as 75% of Sd to reduce length.

Not sure which calculator you're referring to, but using published specs, n = 6.34, (8) vents with Sdv = Sd, my calculator yields ~195.996 L net and ~217.179 L including the vents, with a ~38.25 Hz F3/37.56 Hz Fb.

WRT Xmax, down low, more is better, so 0.8 mm isn't sufficient unless it's being used in a large compression loaded horn or limited BW bandpass alignment. I recommend at least ~6 mm, but if close by neighbors keeps you from playing at higher SPL, you can get by with as little as 3 mm. Still, best to have too much than be caught short........

Since I live down in NASCAR Country, I'm not all that familiar with what's available in Europe.

GM

[Giaime]

Thank you,

thank you very much for your kind reply. So I have to get something with more Xmax. Is there a 10, 12" or maybe a 15" (size is an issue, I'd like to have a small enclosure even sacrificing some extension) from Eminence that you can point me at?

The calculator is here: http://melhuish.org/audio/download/ONKEN_CALC.xls

[GM]

Greets!

You're welcome!

Cyr-Marc makes some assumptions I don't agree with, but the math's otherwise correct. Since the alignment you got wasn't realistic with this driver per se, I assume it's due to you not changing some of the driver specs inputs. He apparently designed it for his way of measuring drivers rather than just inputting T/S specs, so not very user friendly and odds are the average DIYer won't get an accurate calc IMO.

Can't really recommend any driver since you haven't told us what level of performance you want, i.e. LF extension, HF XO point/slope, power handling, etc., what it will XO to, music or HT app, or any size limitations.

GM

[Giaime]

Hello!

Thank you very much.

So instead of using that calc-sheet, should I use standard bass reflex design programs and keep the port area equal the Sd of the cone? I've heard of many people doing this way.

Speaking of my goals, I want something at least 98dB efficient, from 40Hz (flat) to 800Hz (30Hz would be great). It will be powered from a 10-20W tube amp, will play rock (not metal), jazz, blues... it will have horns from 800Hz up. And, of course, cheap is better, and smaller is better. 200 liters are the limit, I can go tall anyway I want, but not larger than 60x60cm base. If it has Eminence woofer it would be great.

Thanks in advance!

[GM]

Greets!

You're welcome! BTW, nice website!

Yes, you can do that if it allows you to choose the number of vents since the extra friction of multiple vents will affect their length.

Hmm, 98 dB/40 Hz eff.......this will require corner loading. That, or a bigger cab up against a wall. Anyway, the Kappa 15" is the only Eminence that comes to mind that will meet these requirements if corner loaded, though the published plot shows a notch filter is required up high. To get to 30 Hz will require corner loading and a bigger cab.

GM