Opinions on portable measurement eq.

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Hi diypole,

I don't have experience with the thing.
However the usefulness of such equipment depends on what you want to measure. For serious design 1/3 octave measurements are however not adequate.
You need a good microphone (with preamplifier), a PC or laptop with a good sound card and good software like Speakerworkshop.
Perhaps you can use the thing as microphone/preamplifier.
 
diypole

Check out SoundEasy software, along with a portable sound card it should do just about anything you need. Personally I use IMP/M from Liberty Audio, but it is no longer available. It is portable, and I have it plugged into a laptop.

I'm interested in your user name and sig line. I've been interested in dipole speakers for quite some time, and in fact built a dipole subwoofer based on Linkwitz' H baffle design. I loved it! Can you private email me so that we can discuss further?

Regards,
Ron
 
looks like this and my laptop may be my best bet
http://www.audioxpress.com/bksprods/kits/kc-cliom.htm
Any opinions?
Hey transducer, Thanks for the link. A pair of Linkwitz w frame dipole subs is what got me started in all this. I mated them to a kef coincident (rdm II with ports stuffed) in the fashion of Gradient revolution http://www.gradient.fi/En/Products/Revo/Revo1.htm
The new found bass detail and speed surprised the heck out of me and anyone I played it for!

Now I am trying to marry a BG neo8 to 2 peerless 10" csx in a dipole mtm. 3 people have heard them in a test baffle with only one peerless and want a pair already(busy christmas)!
Definately we will talk, but now I must run home and rescue the wife from the 3 girls...see you tommorrow.
ps-not like I do this at work or anything:D
regards, Jason
 
Dick,
Thanks for the link. If people think these types of software are accurate enough, I guess I should be asking for opinions on what type of soundcard is best.
On a side note; As for design simulation, there really isn't anything for the types of speakers I am building, which are either all dipole, or mono till 4-600hz and then dipole mid bass. I like all dipole if positioned well into the room because of soundstage depth behind the speakers, but monopole treble makes for easier room placement. When near a back wall the rear radiation of the tweeter will create a hot spot behind the speaker which destroys imaging. Since you can't take advantage of soundstage depth in this position and the baffle becomes infinite towards the high end, a monopole tweeter make sense. Imaging is retained as well as the advantages of reduced mid bass room interaction and more uniform power response. The only way to really model these baffles(and the one I favor anyway), is to build test baffles out of heavy duty corrugated cardboard and listen to a variety of music and test signal cds. Many sides and wings can be easily changed out on a wooden main panel with a screwgun also. I like to change one speaker and listen in relation to the other...

I am ready to take the plunge into measurement equipment due to the fact that I have sold three pairs of my latest design not yet finished, but I can't afford to spend much over $500 US.
Is there any software for sound measurement that will allow me to take advantage of the daq card I have at work? National instruments sound and vibration stuff is xpensive.
Thanks all, Jason
 
diypole said:

I am ready to take the plunge into measurement equipment due to the fact that I have sold three pairs of my latest design not yet finished, but I can't afford to spend much over $500 US.
Is there any software for sound measurement that will allow me to take advantage of the daq card I have at work? National instruments sound and vibration stuff is xpensive.
Thanks all, Jason

Jason, as I mentioned earlier, you should look at SoundEasy, it's under $300, includes a full measurement system plus a distortion analyzer an o'scope, but most importantly, it is a crossover design and optimizer program. Your challenge will be to find a sound card for your laptop, but I think there are a few outboard units that will work.

If you've never done measurements before, I should warn you that you will not be able to get realistic and accurate measurements in the bass region in your home on your dipoles. Typically, you can get down to around 300Hz for a far field measurement in a house. Below that you need a nearfield measurement technique. But that is useless for a dipole, as it doesn't show the dipole rolloff which must be equalized. So you are left with doing an outdoor groundplane measurement, which is full of problems, noise/weather etc. You're in Vermont, similar weather to me (I'm in Ontario). You won't have much opportunity to measure outdoors, especially come Christmas time :D I highly recommend Joe D'Apollito's book Testing Loudspeakers as an excellent reference.

On a side note, I've built a pair of small 2 way monitors, to which I'm thinking of adding a dipole sub like a Celestion SL6000 system. Only prettier ;)

Cheers,
Ron

p.s. did you build the full Phoenix or just the woofers? I've always wanted to hear them, but there is no one near me that has a pair :(
 
Hey Transducer,
Tried to e-mail and pm you, but not able for whatever reason. I checked it out and it looks very good, mais I'm getting a little confused. Seems I can "maybe" save money by buying software that utilizes the computers soundcard, but may have to get a $3-400 soundcard also to get decent speed/resolution. Audio express and Meniscus' print catolog both have measurement system packages for $350-600, which include PCI cards.

What are the advantages/disadvantages of each? Will a run of the mill soundcard be adequate or, better yet; how much resolution do I need? Is it better to go with an outboard device due to noise -period?
Never did build the whole Pheonix: just too much money. Same with the Orion. Guess I've been working on the 'po mans version (translation: no scan speak drivers!pigs) There comes a point were lot's of money brings minute improvements, and I like to stay right below that line.
regards, Jason
 
Jason, try emailing me at ron.steinberg@sympatico.ca

I know that my friend JohnK is using a SoundBlaster value card 5.1, and he's able to get excellent measurements. Also, this software can do digital crossovers in realtime, so you don't even need to build a crossover. The value card doesn't give you the best d/a converters, but it's pretty good according to John. You will get enough resolution out of this as far as I know. You might want to join the SE users group, it's part of Yahoo.

The advantage of SoundEasy over the standalone measurement systems is that that's all they are, measurement systems. There is no design component to them. Now, I use the Liberty Audio IMP/M (no longer available) which is a standalone unit. But at the time this thing was made, there were no all in one units. I'd go for something that did more than measure, but also gave me the capability to design and optimize a crossover, design a box, etc.

I hear you about too much money ;) I've always wanted to do a Phoenix or Orion, but the price tag is just too much. As I said, I'm thinking of dipole bass with enclosed mid and tweeter. Also have another idea using a stacked dipole pair of woofers, sort of like the W frame Linkwitz design, but stacked, with a mid and tweeter on top.

Cheers,
RonS
 
Ron, transducer is now in my address book. Thanks for the details, the realtime digital cross sounds like tweak heaven!
I have thought about the stacked w frame myself. I am trying to design to be able to do this, which requires getting the mids to cross low enough so as not to excite the cavity resonance on the w frame too much. Straight firing h frame sub can be crossed higher, but the w frame gets so LOW for a dipole..ahhh trade offs.
regards, Jason
 
The reason I don't like the straight H frame woofer is because I find it rocks. When I use my turntable, every time I raise the arm, the woofer actually rocks back and forth! I do notice slight vibrations in the back and forth direction as well, so I'm hesitant to use it as a base for a mid/tweet.

I don't have the latest version of SE, so I haven't tried the digital crossover yet, but it sure would make trying out different circuits a breeze.

Cheers,
Ron
 
Assuming you have the woofers wired out of phase, have you thought about bolting the bottom to something to add mass? A base which slopes to the floor in the front and back might look aesthetically pleasing while helping to smooth the transition from baffle to floor.
Jason
 
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