I Tuned my system in room with a similar setup (minidsp) and although I got the fr looking good it never sounded right. 90% of the problem was inexperience understanding what I was really seeing.
I have Joe's book also but never quite clicked with the process.
Remember to turn off all your mini dsp eq filters once in a while when tuning, its quite enlightening.
I have Joe's book also but never quite clicked with the process.
Remember to turn off all your mini dsp eq filters once in a while when tuning, its quite enlightening.
Now that you have a powerful DSP crossover at your disposal, you need to get out of the stone age with your measurement techniques!
An RTA or SPL meter is NOT how you should be taking measurements. You are measuring the room plus the loudspeaker with this very crude approach. What you want to do is measure the loudspeaker independently of the room. Then you develop the crossover based on those measurements. Then you measure the performance of the loudspeaker in the room. Then you EQ out peaks and nulls when appropriate, reposition the speakers in the room, etc.
Many people, including myself, use ARTA for measurements and use the technique that I describe here:
http://audio.claub.net/tutorials/FR measurement using ARTA.pdf
You can download a free "trial" copy that is fully functional. You will need a computer, mic, preamp, and soundcard. I use an M-Audio Firewire 410 that is all of these. You can find them on Ebay. You will need to be able to make a Firewire connection between computer and 410. There are other ways to get the signal in and out of the computer, too.
Just don't use an SPL meter!
-Charlie
An RTA or SPL meter is NOT how you should be taking measurements. You are measuring the room plus the loudspeaker with this very crude approach. What you want to do is measure the loudspeaker independently of the room. Then you develop the crossover based on those measurements. Then you measure the performance of the loudspeaker in the room. Then you EQ out peaks and nulls when appropriate, reposition the speakers in the room, etc.
Many people, including myself, use ARTA for measurements and use the technique that I describe here:
http://audio.claub.net/tutorials/FR measurement using ARTA.pdf
You can download a free "trial" copy that is fully functional. You will need a computer, mic, preamp, and soundcard. I use an M-Audio Firewire 410 that is all of these. You can find them on Ebay. You will need to be able to make a Firewire connection between computer and 410. There are other ways to get the signal in and out of the computer, too.
Just don't use an SPL meter!
-Charlie
I don't recall having a copy , feel free to help a brother out and send me yours ..
I don't recall having a copy , feel free to help a brother out and send me yours ..
I left it behind when I moved. You don't want to torture yourself with that book anyway. You can get more comprehensive info on the web or in these forums.
If you have a thin skin, please skip this post. I don't wish to offend anyone, but there is some tough reality to be heard.
As I have suggested, a beginner needs to first get some basic electronics. If you understand basic electronics, then the book is very straight forward. Maybe it is a good test. If you don't understand it, you are already in over your head and should back up to fill in the missing knowledge. Start in the first chapter and when you hit a snag, come ask specifics.
I never said he was a great writer, but he does know speakers. If you think his book is hard to read, go read the real engineering level stuff on Linkwitz. Actually, he makes it pretty simple as Siegfried is a long time DIY supporter. Yes, he is a real engineer.
There is a reason engineers have to go to school. Speaker design is engineering. If you don't want to do engineering, stick with building established plans. Plugging in numbers on a web cheat sheet does not an engineer make nor do you learn much.
Speaker building is actually a great way to learn electronics. An LC network is an LC network is an LC network. Ohm did not care what you were building. Actually, he was really into sound, so he might be thrilled. Do yor homework. Ask specific questions.
ARTA is really easy to use. Several folks here have done great quick start guides. Play with it until you understand what you are seeing. In time, you will get a good feel what is what.
I also have Sound Easy. Powerful, but hard to use and expensive. If you want to see a book ( 300 some pages) that really assumes you are an expert first, download the manuals for SE. He assumes you already understand all the complexities of measuring in the digital domain.
For low frequency measurements, I revert back to True RTA quick sweep. For a sub, the room is everything. For the mains, your brain processes the room and makes some adjustments. A perfectly flat response at your listening position would sound odd. Tried it. Terrible.
My method is to do nearfield and 1 meter measurements to get a reasonably well behaved speaker. I then put it in place and bring out several CD's I know well. Joni Mitchel's voice is difficult to get right, as is Joan Baez. A bit of classical guitar, a bit of the Saber Dance, as bit of Harry James. Voice by ear. My experience is if I get Joni and Joan right, everything else sounds fine.
I also have Sound Easy. Powerful, but hard to use and expensive. If you want to see a book ( 300 some pages) that really assumes you are an expert first, download the manuals for SE. He assumes you already understand all the complexities of measuring in the digital domain.
For low frequency measurements, I revert back to True RTA quick sweep. For a sub, the room is everything. For the mains, your brain processes the room and makes some adjustments. A perfectly flat response at your listening position would sound odd. Tried it. Terrible.
My method is to do nearfield and 1 meter measurements to get a reasonably well behaved speaker. I then put it in place and bring out several CD's I know well. Joni Mitchel's voice is difficult to get right, as is Joan Baez. A bit of classical guitar, a bit of the Saber Dance, as bit of Harry James. Voice by ear. My experience is if I get Joni and Joan right, everything else sounds fine.
Well, I understand it now.
After studying that book for a year, Trying to make sense of the horrible writing style. My problem was with the presentation. I mean, he will present a graph and won't talk about what it represents until 5 pages later. So, you end up flipping back and forth trying to figure out what the heck he's talking about.
Why write a book on understanding something when you have to already understand it before you read it?
My point is, there are better examples of his teachings on the web.
After studying that book for a year, Trying to make sense of the horrible writing style. My problem was with the presentation. I mean, he will present a graph and won't talk about what it represents until 5 pages later. So, you end up flipping back and forth trying to figure out what the heck he's talking about.
Why write a book on understanding something when you have to already understand it before you read it?
My point is, there are better examples of his teachings on the web.
Horrible writing style? I have the same book and found it to be VERY well written and one the BEST texts on measuring. I think you shouldn't berate the book if it's your own comprehension that is at fault. More study and knowledge seems to be what you need. It's not for the beginner but does show what is required to design a good speaker.
I'm glad that you grasped it so easily.
I think it's poorly written.
For reasons that I stated.
It's just an unorganized piece of literature.
It's just not very accessible for beginners, he doesn't state that it's advanced in the beginning of the book, in fact it starts out with very beginner like text and examples. Then it just spirals out of control.
Like I said. I understand it now, 8 years later, but only because I've been in the game for a while.
It's just not a book for beginners, although it comes off that way at the start of the book.
I'm only stating the fact that it shouldn't be suggested to a biginner, like it has been in this thread.
I think it's poorly written.
For reasons that I stated.
It's just an unorganized piece of literature.
It's just not very accessible for beginners, he doesn't state that it's advanced in the beginning of the book, in fact it starts out with very beginner like text and examples. Then it just spirals out of control.
Like I said. I understand it now, 8 years later, but only because I've been in the game for a while.
It's just not a book for beginners, although it comes off that way at the start of the book.
I'm only stating the fact that it shouldn't be suggested to a biginner, like it has been in this thread.
I also have the 4 volume anthology Loudspeakers published by the AES. f you think Joe D-Apolitto's book is difficult, then try reading through that, although I have learned a lot from those too. Nothing doing well comes easily but takes lots of study and dedication. I think suggesting to a beginner Joe D-Apolitto's book is the right thing to do just to show them what they don't know yet, but if they apply themselves to learning, then it will be worthwhile.
Great results are possible with both MLS and sweep methods. Both are capable of measurement from virtually DC to Nyquist. However: MLS is more sensitive to noise in environment. Swept sine has better S/N than MLS. MLS brings out worst in slewing behavior of drivers and electronics. And: REW has perfectly useful gating features too.
yes I used to solely use MLS signals but decided to try swept sine (so I could get distortion measurements) and actually found that I got better measurements with swept sine than with MLS. This was using holm impulse.
Pink noise measurements in REW (using the RTA) are good at the listening position as well, especially if you play around with the averaging. see this post by Markus for some ideas http://www.diyaudio.com/forums/mult...y-pattern-stereo-speakers-40.html#post2737602
Tony.
Pink noise measurements in REW (using the RTA) are good at the listening position as well, especially if you play around with the averaging. see this post by Markus for some ideas http://www.diyaudio.com/forums/mult...y-pattern-stereo-speakers-40.html#post2737602
Tony.
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Strange, because I seem to get identical results. Wonder what the difference is?
From memory I found (at least where I was measuring) that I got less noise with the swept sine compared to MLS. I think that they both gave the same FR but I think that I could move the gating lower with the swept sine than I could with the MLS without the higher frequencies looking like they needed a shave I'll have to be a bit more scientific the next time I'm doing some measurements.
Tony.
I'll have to be a bit more scientific the next time I'm doing some measurements. Tony.
You have a big dead room? At 1/3 octave smoothing, or nearfield, they are close. At 1M, 1/24 the differences are large. Below about 200 Hz, I use sweep.
From memory I found (at least where I was measuring) that I got less noise with the swept sine compared to MLS. I think that they both gave the same FR but I think that I could move the gating lower with the swept sine than I could with the MLS without the higher frequencies looking like they needed a shave
Tony.
Are you sure it is noise, not diffraction, reflection, basket reflections and other nasties?
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