Testing and measuring Spirula shaped speakers based on Akamake's project designed by Ondra Chotovinsky.

[Walt B]

Hi Folks, this is my first post in here I hope I tailoret it to the right section.

I recently finished my last pair of custom made speakers based on Akamake's project designed by Ondra Chotovinsky.

These are the details:

Drivers: Mark Audio Alpair 7ms
Revc= 7.200 Ohm
Fo= 74.724 Hz
Sd= 50.270 cm²
Vas= 4.968 Ltr
Cms= 1.384m M/N
Mmd= 3.072m Kg
Mms= 3.277 g
BL= 3.859 TM
Qms= 2.350
Qes= 0.744
Qts= 0.565
Levc= 124.716u H
No= 0.270 %
SPLo= 86.324 dB
Xmax = 4.5mm 1 way mech
PWR= 15 Watts Nom

Box: Custom Spirula shaped printed in one piece using SLS printer using Nylon 12 material powder
Mass: 2,5 KG per unit
Supra Classic-2.5 Speaker wire (13 AWG) for internal connections
Dayton Audio BPP-SN Premium Binding Post
Dayton DSS3-SN speaker spikes

Actually I'm using a Fosi Audio BT20A PRO Class D amplifier powering these speakers. By the way I thing this is a great one from a respectable company.

This is how it looks like:

So basically, what I need is to take the measurements for:

- Frequency Response
- THD down to < 0,1% and THD at high SPL levels (up to drivers thermal or mechanical limit)
- Waterfall / spectral decay

Sumarizing what I need is:
Best affordable setup for reliable measures, what mic and what software do you recommend for entry level.

Just in case I have purchased a DaytonAudio iMM-6 mic, for tunning my daughter's violin, do you think is too basic?

I will appreciate any help you may provide.

Best regards,

Walt B.

 

[cyrano]

Looks good, if you're into that kind of thing. But how do these sound?

As long as you want to compare your measurements only with your own measurements and with what you're hearing, any decent mic will do.

After all, the room the speakers are in will produce more deviation than the difference between measurement mics. The low end is just a small diameter electret, as these are usually flat. They are a bit less noise wise, but that shouldn't affect frequency curve measurements.

When you start comparing your measurements with others', a UMIK BK1 is the first step up, since it's level calibrated. It is, however, a USB mic. It's easier to use a simple audio interface, with input and output from one device. Two or more devices might give some trouble when routing the IO to the software.

When it comes to software, REW (Room EQ Wizard) is probably the most used. It's very complete and free. It also has a very knowledgeable forum. There are others, like OpenSoundMeter (free) or ARTA. They have their own pros and cons, you have the choice...