Hello!
I've searched around the forums quite a bit and just couldn't find any useful guide on what I need...
What I'm looking for is a speaker measurement setup (acoustics and even better impedance too). I'm prepared to pay a reasonable amount for it if it will match the following criteria:
- easy to use, intuitive front end.
- includes everything in one box (mic, software, any dongles etc.)
- only requires a computer with a "normal" soundcard to work correctly
- can enable me to achieve great speaker designs!
The reason for this is two-fold. Firstly, some time ago I bought a speaker kit (Intertechnik/Audiocom Seas Pontus) and wasn't entirely happy with the sound, so I changed the crossover, by guesswork. The sound is better, but I would like to take it even further by measuring the drivers' individual outputs and total output to optimise the crossover as far as possible.
Secondly, quite a few people have asked if I could design and build speakers for them. They know I don't have the measurement setup but ask anyway! One good friend has gone as far as offering payment and suggested I could use that to buy software and get the job done really well. He's right of course, this is the way forward.
So I need some help in deciding what to buy or put together. A name I've seen used a lot is Speaker Workshop, and I notice that it's freeware, which is nice!
It probably doesn't help because I don't have a calibration chart for it but I have a general purpose microphone and preamp. I have an ageing but adequate pc: 2.3ghz Athlon, 1gb RAM, Soundblaster Live Player 1024 sound card.
I'm not sure where to start with this, hence this thread! I just need a push-off in the right direction.
Thanks for any help you can offer me.
Simon
I've searched around the forums quite a bit and just couldn't find any useful guide on what I need...
What I'm looking for is a speaker measurement setup (acoustics and even better impedance too). I'm prepared to pay a reasonable amount for it if it will match the following criteria:
- easy to use, intuitive front end.
- includes everything in one box (mic, software, any dongles etc.)
- only requires a computer with a "normal" soundcard to work correctly
- can enable me to achieve great speaker designs!
The reason for this is two-fold. Firstly, some time ago I bought a speaker kit (Intertechnik/Audiocom Seas Pontus) and wasn't entirely happy with the sound, so I changed the crossover, by guesswork. The sound is better, but I would like to take it even further by measuring the drivers' individual outputs and total output to optimise the crossover as far as possible.
Secondly, quite a few people have asked if I could design and build speakers for them. They know I don't have the measurement setup but ask anyway! One good friend has gone as far as offering payment and suggested I could use that to buy software and get the job done really well. He's right of course, this is the way forward.
So I need some help in deciding what to buy or put together. A name I've seen used a lot is Speaker Workshop, and I notice that it's freeware, which is nice!
It probably doesn't help because I don't have a calibration chart for it but I have a general purpose microphone and preamp. I have an ageing but adequate pc: 2.3ghz Athlon, 1gb RAM, Soundblaster Live Player 1024 sound card.
I'm not sure where to start with this, hence this thread! I just need a push-off in the right direction.
Thanks for any help you can offer me.
Simon
I use speaker workshop(free) and built the jigs, mic, cables myself. It takes a while to learn SW but it work great, and you can't beat the price.
I've heard good things about CLIO but it is fairly expensive.
I've heard good things about CLIO but it is fairly expensive.
I've also just downloaded Arta, http://www.fesb.hr/~mateljan/arta/index.htm, which has a free demo that seems to be very useful.
I just used it to measure my laptop's sound card, and I found that I have about 0.15% THD+noise, and a frequency response that's fairly flat between 80 hz and 10 khz, but down 3db at 40 hz and 20 khz.
I would say that my sound card is probably good enough to design speakers if I don't worry about competing with super high-dollar speakers. It would fall short if I wanted to very accurately measure the distortion of a driver, since the very best drivers have distortion components that are even lower than the noise floor of my sound card. The THD of the laptop is actually much better- about 0.015%, but with the noise floor so high there's really nothing I can do to get better measurements.
A quick and cheap thing to see if your present sound card is good enough for your purposes is to get a patch cable to connect your sound card's input and outputs to perform the same tests I did.
Also, I have a Behringer ECM8000 measurement microphone. They are available now for around $40. It is definitely the right tool for the job, and operates at a much higher level of performance than my laptop. You should be able to pick one up cheaply if you don't purchase a package that's all inclusive. Just be aware that it requires phantom power.
I just used it to measure my laptop's sound card, and I found that I have about 0.15% THD+noise, and a frequency response that's fairly flat between 80 hz and 10 khz, but down 3db at 40 hz and 20 khz.
I would say that my sound card is probably good enough to design speakers if I don't worry about competing with super high-dollar speakers. It would fall short if I wanted to very accurately measure the distortion of a driver, since the very best drivers have distortion components that are even lower than the noise floor of my sound card. The THD of the laptop is actually much better- about 0.015%, but with the noise floor so high there's really nothing I can do to get better measurements.
A quick and cheap thing to see if your present sound card is good enough for your purposes is to get a patch cable to connect your sound card's input and outputs to perform the same tests I did.
Also, I have a Behringer ECM8000 measurement microphone. They are available now for around $40. It is definitely the right tool for the job, and operates at a much higher level of performance than my laptop. You should be able to pick one up cheaply if you don't purchase a package that's all inclusive. Just be aware that it requires phantom power.
MJL21193 said:
Thanks, I will have more of a look at Speaker Workshop. No point spending money if I don't need to.
Simon
joe carrow said:
Thanks for the tips. ARTA looks like it could be handy, lots of help guides there. I'm not interested in going as far as THD tests right away, so I probably needn't worry about my sound card yet.
If you've used both of these software tools, which would you recommend I spend more time trying to get my head round?
As for the mic., something like your Behringer ECM8000 sounds ideal. A quick look on Ebay UK reveals they're about twice what you paid, annoyingly, but affordable.
Do you think my cheap mic. preamp will provide phantom power? I will have a look when I remember and I'm at home. Does the Behringer connect via xlr?
Thanks for the replies so far.
Simon
I have a Thiele-Small measurement toolkit in development on my website. Probably not as press-and-go as Speaker Workshop, but it's there if you want to take a look.
Ultimately I want to develop the toolkit into a single user-friendly spreadsheet.
Ultimately I want to develop the toolkit into a single user-friendly spreadsheet.
Thanks Richie,
That calculator works nicely, well, with randomish numbers put in it seems to make sense! But I need the physical setup to actually measure driver impedance too. I tried something from a textbook before and got vaguely believable numbers but my method was criticised and so I really need to know how to do this properly but as easily and cheaply as possible!
Simon
That calculator works nicely, well, with randomish numbers put in it seems to make sense! But I need the physical setup to actually measure driver impedance too. I tried something from a textbook before and got vaguely believable numbers but my method was criticised and so I really need to know how to do this properly but as easily and cheaply as possible!
Simon
Fantastic guide there Rich, thanks. There are a few bits I don't understand, such as why we want Fb and a port on the test box. Is this the way to work out the tuning frequency of your finished speaker? Or is it a part of measuring drive unit params?
I think when I had a go at measuring a driver I used the voltage source method and it seemd as though my multimeter wasn't accurate enough to give great results (very rough I thought). To calculate Vas I did the added mass method, which again, perhaps wasn't too accurate. Building a test box is a mega-pain though! How strongly do you recommend this?
Thanks,
Simon
I think when I had a go at measuring a driver I used the voltage source method and it seemd as though my multimeter wasn't accurate enough to give great results (very rough I thought). To calculate Vas I did the added mass method, which again, perhaps wasn't too accurate. Building a test box is a mega-pain though! How strongly do you recommend this?
Thanks,
Simon
Hi Simon,
I'm rebuilding my jig as we speak which includes the wallin jig, mic preamp, and single channel chipamp in one box for doing T/S and acoustic measurements.
I use ARTA (free version) for acoustic measurements, and import the measurements into SW (Speaker Workshop) for xover design etc. I use SW to manage the projects and for T/S measurements (I haven't tried limp yet for T/S - part of the ARTA suite).
You can make your own mic pre (search wallin preamp v2), and use the Panasonic WM-61 Electret to make a cheap but excellent mic/preamp combo.
You'll see it all in action at the UKFest07 😉
Vikash
I'm rebuilding my jig as we speak which includes the wallin jig, mic preamp, and single channel chipamp in one box for doing T/S and acoustic measurements.
I use ARTA (free version) for acoustic measurements, and import the measurements into SW (Speaker Workshop) for xover design etc. I use SW to manage the projects and for T/S measurements (I haven't tried limp yet for T/S - part of the ARTA suite).
You can make your own mic pre (search wallin preamp v2), and use the Panasonic WM-61 Electret to make a cheap but excellent mic/preamp combo.
You'll see it all in action at the UKFest07 😉
Vikash
Simon,
The test box is not vented. Maybe you misunderstood the bit about measuring your own vented box for Ql?
As for making a test box, it's not really that hard IMO. As it's only a test box, it can be any old rough material, doesn't even need to be thick or strong or braced etc, as it only ever sees small signals. If you DIY speakers quite regularly you can just build a couple of boxes to suit most speakers, by making the front panel take a baffle adaptor to suit the individual speaker. Or you might be able to get away with clamps.
The test box is not vented. Maybe you misunderstood the bit about measuring your own vented box for Ql?
As for making a test box, it's not really that hard IMO. As it's only a test box, it can be any old rough material, doesn't even need to be thick or strong or braced etc, as it only ever sees small signals. If you DIY speakers quite regularly you can just build a couple of boxes to suit most speakers, by making the front panel take a baffle adaptor to suit the individual speaker. Or you might be able to get away with clamps.
Vikash said:
Hi Vikash,
Yes, I should see it all there! I'll see how it's supposed to be done 😉
So it looks like I need ARTA and Speaker Workshop, plus I need to source a suitable mic and preamp, and build a test box! This is very daunting indeed. I guess I can start trying to learn the software pretty much straight away. I could get rough measurements with my cheap dynamic mic and Maplin preamp, which would do for the purposes of learning something!
Simon
richie00boy said:
Ahha, so the final page of http://www.readresearch.co.uk/loudspeaker_papers/measuring_ts.pdf is just a sort of extra for later in the design stage of a vented box?
SimontY said:
I think Vik is offering a kit onebox solution - at a reasonable price I'm sure - so don't really see what's so daunting.
SimontY said:
Basically yes. I thought that would have been clear. Maybe I need to take another look at it.
I don't see how Vikash is offering anything, after reading hi spost again. Your guide is clear most of the way through, Rich, but in places I was a little lost. It's hard to proof-read such a guide when you already have the knowledge.
Simon
Simon
Maybe I misunderstood his post then! Although I also can see how my idea of daunting can be quite different to another persons... Especially if you are new to speaker design.
Yes, I didn't release the paper for ages because I was conscious it may still be difficult to digest for beginners, despite a lot of time spent on it. Hence why it's all still labelled work in progress - with feedback from people like you I can make it better.
Yes, I didn't release the paper for ages because I was conscious it may still be difficult to digest for beginners, despite a lot of time spent on it. Hence why it's all still labelled work in progress - with feedback from people like you I can make it better.
SimontY said:
Just a thought- you might want to take a look and make sure that the sound card is not REALLY bad. If there was enough distortion, it might matter against your other measurements.
Sorry, I haven't used them on any speakers yet- I'm fairly busy with other things lately. Fortunately it sounds like a few other people have shown up on this thread with some experience.
Sorry to have given you misinformation! I really thought it was cheaper. I paid $75 for mine in 1999, when its list price was over $100. I had recently read on a forum that they were available for the cheaper price I had stated, and I'm sorry to say that I didn't verify it at the time. They're fairly well made, though, so I wouldn't feel bad about getting a used one.
Again, sorry about that.
The Behringer connects via XLR. If your mic preamp has XLR connections, it seems likely that it has phantom power available. The thing is, as far as I know it would have a switch to turn it on and off. Dynamic microphones don't require phantom power, so most microphone preamps that I've come across have a switch. My behringer mixer has one. Some of the larger mixer boards I've used have had them.
Speaking theoretically, it would probably be easy to make an auto-detect circuit that would provide phantom power only when required. Whether that's common in the world of audio devices, I have no idea.
Thanks for the tips Joe! There's no need to apologise on behalf of "rip-off Britain". It's well accepted here that we have to pay more than people in other countries for nice things, or any things!
I would rather spend 40 UK Pounds than go through the process of sourcing the parts and putting together a DIY effort, as I'm too busy right now and need to get something sorted fairly soon ideally.
Hmm, I think the mic pre has 6.5mm jack connections so I guess my luck's out on the phantom power. I'll look at it when I get home later. Is the power just a third connection with some voltage available on it?
Cheers
Simon
I would rather spend 40 UK Pounds than go through the process of sourcing the parts and putting together a DIY effort, as I'm too busy right now and need to get something sorted fairly soon ideally.
Hmm, I think the mic pre has 6.5mm jack connections so I guess my luck's out on the phantom power. I'll look at it when I get home later. Is the power just a third connection with some voltage available on it?
Cheers
Simon
CPC are doing the ECM8000 for £41.71. Spend another fiver an you'll get free delivery on that too.SimontY said:
I don't do the mic preamp kits anymore Rich - far too much trouble to make the kits up 😉 I still have the PCB's and Panny electrets though for those wanting to go the diy route.
- Status
- Not open for further replies.