Measuring speakers for numpties

A place for DIY project discussions.
User avatar
karatestu
Posts: 2027
Joined: Sun Jan 08, 2017 4:40 pm
Location: North Yorkshire
Great Britain

Measuring speakers for numpties

Unread post by karatestu » Mon Oct 07, 2019 1:32 pm

Well to celebrate my 2000th post I have started this thread. Sorry Doc :pray: It was a toss up between this and how to power my stereo from the over head power lines of HS2 ( a couple of thousand volts I believe :shock: ).

I have always said I was not interested in taking measurements. Now you know not to take any notice of anything I say :grin: I have very recently got the urge to start taking measurements of my speakers. Not that I don't trust my ears but if there are small changes I can make for a better outcome without changing the design principals (3 way, semi omni, isobaric, no xovers) then I don't see the harm in it.

So for in room measurements I will need the following (I think?)

laptop...……………….. tick
REW software for laptop - (free?)
minidsp miniDSP UMIK-1 Omni-Directional USB Measurement Calibrated Microphone - £93 approx.

Will this little lot be good enough and do everything I want ?
DIY inspired by Richard "The Doc" Dunn RIP

Vinyl-ant
Posts: 277
Joined: Sat Jul 01, 2017 12:51 pm
Location: South yorkshire
Contact:
Great Britain

Re: Measuring speakers for numpties

Unread post by Vinyl-ant » Mon Oct 07, 2019 1:44 pm

For pretty rough measurements you can use a phone app called spectrum analyser, which will get you in the ballpark
I've used this to measure all mine. It is not the most accurate measurement method, but it is good for looking broadly at what a speaker is doing in room.
I used it with my metronomes to nail down the inductor value to cut the top off the 6" driver and blend it with the tweeter cap value.
It will show peaks and dips in the in room response.
You will need to either burn pink noise or a log frequency sweep a CD and play it, through the speakers or have some other way of playing the pink noise or sweep through the speakers.
Then once you have measurements, interpret them. Which is the hardest part.
BTE designs type 2 lenco, Audio Technica AT1100 dynavector dv20a2 (his), JVC QL-Y5F HANA sl (hers)
Benedict audio hothead mm phono stage with borrowed LDA ha1 mc stepup
BTE designs type 1 custom Khozmo shunt build passive pre
PASS F5 dual mono Power amp
modified Philips cd371
Squeezebox classic
fane 15" sb speakers
BTE designs balanced power supply

User avatar
karatestu
Posts: 2027
Joined: Sun Jan 08, 2017 4:40 pm
Location: North Yorkshire
Great Britain

Re: Measuring speakers for numpties

Unread post by karatestu » Mon Oct 07, 2019 2:04 pm

Cheers Ant :guiness;

I don't have a smartphone so using that app is impossible. The only thing i have available is a windows 10 laptop.

I believe if i install REW it includes a signal generator ? I then need to work out how to connect the laptop to the hifi and use the signal generator and the measurement at the same time.
DIY inspired by Richard "The Doc" Dunn RIP

User avatar
karatestu
Posts: 2027
Joined: Sun Jan 08, 2017 4:40 pm
Location: North Yorkshire
Great Britain

Re: Measuring speakers for numpties

Unread post by karatestu » Mon Oct 07, 2019 7:06 pm

Ďone a bit of reading about and the faff and time involved doing this properly has put me right off.

This is supposed to be an enjoyable hobby. All that i have read so far seems to point to it being more like a chore .
DIY inspired by Richard "The Doc" Dunn RIP

antonio66
Posts: 105
Joined: Mon Jul 29, 2019 8:16 am
Great Britain

Re: Measuring speakers for numpties

Unread post by antonio66 » Mon Oct 07, 2019 7:11 pm

Do you have a dac that will accept one of your outputs from your laptop?

User avatar
karatestu
Posts: 2027
Joined: Sun Jan 08, 2017 4:40 pm
Location: North Yorkshire
Great Britain

Re: Measuring speakers for numpties

Unread post by karatestu » Mon Oct 07, 2019 7:14 pm

Hi Dave.

I have the £5 Chinese dac but would have to build a psu.
DIY inspired by Richard "The Doc" Dunn RIP

User avatar
Lindsayt
Posts: 2795
Joined: Fri Jul 13, 2012 9:06 pm
Marshall Islands

Re: Measuring speakers for numpties

Unread post by Lindsayt » Tue Oct 08, 2019 2:01 am

Will you be doing single cycle sine wave signal tests at 40 to 80 hz? EG at 40 hz the test would last one fortieth of a second.

The sort of thing Rudy Bozak used to measure way back in the 1960's as a demanding test of how speakers handle bass transients.
You don't get results in numbers, but you do get visual results that show how shockingly bad speakers are in this respect - especially slimline ported speakers.

Just thinking if you're going to measure your speakers, you might as well measure something interesting and something that no modern speaker manufacturers nor magazines appear to do - presumably because they'd be too embarrassing.

User avatar
karatestu
Posts: 2027
Joined: Sun Jan 08, 2017 4:40 pm
Location: North Yorkshire
Great Britain

Re: Measuring speakers for numpties

Unread post by karatestu » Tue Oct 08, 2019 5:56 am

Hey Lindsay. All i was going to do was a simple frequency response. Turns out it's not that simple after all. Read a Tony L thread of 11 pages on pfm and it put me right off.
DIY inspired by Richard "The Doc" Dunn RIP

antonio66
Posts: 105
Joined: Mon Jul 29, 2019 8:16 am
Great Britain

Re: Measuring speakers for numpties

Unread post by antonio66 » Tue Oct 08, 2019 6:37 am

karatestu wrote:
Mon Oct 07, 2019 7:14 pm
Hi Dave.

I have the £5 Chinese dac but would have to build a psu.
Did it not come with it's own cheap power supply?

User avatar
karatestu
Posts: 2027
Joined: Sun Jan 08, 2017 4:40 pm
Location: North Yorkshire
Great Britain

Re: Measuring speakers for numpties

Unread post by karatestu » Tue Oct 08, 2019 6:57 am

No psu included. I have the parts to knock one up though
DIY inspired by Richard "The Doc" Dunn RIP

Post Reply