Recommendations for capable but intuitive beginners measurement set up

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#101
Dave Bullet said:
To prove the accuracy of the combined driver measurement method to get Z, use derived phase and not measured phase...., here is a commercial speaker I redesigned from a 2 way TMM layout to 2.5 way TMM with Tweeter replacement (brand / model entirely). Blue is final speaker measurement, red is the simulation
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Cool Dave. We each find what works for us, huh? 🙂

I only use measured phase.
(But that said, it's so stinking easy to use measured phase when phase is flat (like i always use) throughout the passband and summation ranges.
 
#102
yes - I have no issue with dual channel setups. I'm just supporting the other side (USB only), and I'm not meaning you, but some seem to portray it as somehow sub-standard and imply you won't get good results.

If I could get my dual channel setup working again with a reliable USB device I might....

But let's get back to the OP's question at hand of a beginners setup.

Options:

A) USB mic

1. Buy a USB mic (calibrated)

B) Dual channel setup

1. Buy a dual channel USB audio device with phantom mic power - e.g. Scarlett
2. Buy an XLR microphone (calibrated)
3. Buy an XLR cable
4. Buy a splitter / loopback cable

For a beginner, I know which one I'd recommend especially when costs are involved.
 
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#104
Well, I don't know how much cash the OP has 🙂 I just know as a newbie, I had a budget for my first self build, then when I added in all the other setup costs (not just measurement equipment but any cabinet making supplies / tools) that first build becomes quite expensive. Of course, over time it pays for itself over and over again.
 
#105
True, but in this instance I’m concentrating on ”A” vs. “B” with regard to microphone setup.

Cross Spectrum in the states is about $120 for UMIK-1 vs. about $100 for Dayton EMM-6 + another $140 for a UMC204HD and patch cord: so cost-wise it’s about double BUT that cost is still pretty low overall; I don’t think that extra $120 is a substantive “sticking-point” for most people serious enough to start doing measurements for loudspeaker design.

Biggest hassle/obstacle by far for me is setup to achieve good consistent results, and that was true when I started and still is. :blush:
 
#106
I never bothered with a cross spectrum labs UMIK-1 - I'm just using the vanilla one for $79. I'm not sure how "out" it is and where in the curve. Maybe 1dB here or there? for crossover design through - nearly all of these capsule based mics seem to be near 0dB and consistent around 1 - 3KHz. I did compare my ECM8000 which I self calibrated and UMIK-1 and they compared pretty favourably across the spectrum. Fair enough re cost.
 
#107
UMIK-1 is mostly off above 6kHz? maybe as much as 2.5db (nearing 15kHz) if memory is correct (I have it). I think it was also off at least .5db below 100Hz (which surprised me). This is in comparison to an ACO mic. which itself may be off by .5-1db above 10 kHz. Still, to me it’s worth the $31 up charge from $79 though I’m not taking a beating on shipping.

Yeah: 1kHz is perfect - it’s great for Spl-metering in REW with its own curve. 🙂
 
#108
mark100 said:
Good to know, thx.
Do you know of any other USB cards having such a problem? Or has it seemed confined to that unit?
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No, but we here discussed the probability a lot of modern interfaces have programmable on board signal processing (audio effects) after the A/D (I did mention that Xmos chip, didn't I?) and that in itself is a possible problem, there can thus be latency issues between the D/A and the A/D. A simple old school card only has the synchronous A/D-D/A IC directly hooked up to the USB driver chip. Like some old Yamaha Audiogram here I still use for its simplicity, while Windows still supports it. macOS does too, but that isn't a surprise to me.
 
#109
A4eaudio said:
Purchase:
1) Calibrated xlr microphone - Dayton EMM-6 is a good bargain in the US, not sure about UK although it is available at Soundimports. A search of diyaudio will find plenty of mic recommedations.
2) Preamp - Behringer UMC202, Steinberg UR22mkii, Motu M4, etc. The Behringer is on sale at a nice price at Sweetwater but probably irrelevant for the UK.
3) Some mic and other cables (and maybe adapters) for the loopback wiring
Click to expand...
I've been using a UMIC-1 for a while and have been annoyed with it, so I bought all this stuff (UMC202 and EMM-6) to try.

I went through the soundcard calibration process and was surprised at the curve that came back. I'm just looking for a sanity check, could this be correct?
I'm surprised at the low frequency drop off.
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#110
That does NOT look right to me. My first guess is that it's not the soundcard but something wrong with the calibration process. I'm not too sure on the settings but two things I notice that MIGHT be a problem. I think you should use Main Speaker test signal rather than subwoofer. And I think you should have your Timing Reference Output and Loopback Input set to "L" with a cable running from the L-out on the back of the inerface to the L-in on the front.

If that doesn't help, post an update and hopefully someone who knows more than me can help.
 
#114
I am interested in jumping into measurement for crossover optimation on a couple of my hobby speaker projects. Reading thru this thread now a bit overwhelmed.

I have a FocusRite Scarlett 2i2 3rd gen. Is this audio interface able to work with one of the calibrated XLR mics mentioned in this thread to get acceptable readings? (it does has phantom power)
https://us.focusrite.com/products/scarlett-2i2-3rd-gen

It plugs into my lenovo laptop via a USB C plug.
 
#115
Focusrite Scrlett 2i2 appears to have 2 xlr inputs, 2 electric guitar inputs, and one USB output. Appears to be an A/D. I would say bring up Audacity on the laptop with a USB input, plug in the mike, play some music on the hifi, and look for the waveform coming in. Sometimes I have to use jack accessory to make Audacity see inputs, sometimes not.
 
#118
That one has been spoken of and roughly tested on another (Dutch) DIY audio forum. Bottom line: unless you want to be on your own with quite some hassle, don’t.

For dual channel you need dual synchronous inputs. I don’t recall this having that. Noise seemed to be problematic too.

If one wants an all-in-one solution, Clio (Pocket) stays unsurpassed. Expensive? A set of Purifi drivers sets you back further. All others better stick to the two- or three box solution of separate USB audio interface, amplifier and impedance box.
 
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