[ooheadsoo]

I don't have that problem with my meter/test tones  

I use foobar2000's built in generator on the computer.

[Ethan Winer]

Jeff,

> Are there any measurements that can be performed to measure how well a driver tracks the input signal? <

Yes, the kind of nonlinearity you're describing will show up in standard THD and IM distortion tests.

> While listening to a tone for 30 seconds, my meter can change 8db. Does anybody have an explanation for this <

That sounds like what happens with pink noise, as opposed to steady sine wave tones. If you're playing a single steady tone and the level varies more than a tiny fraction of a dB, and you're not moving around in the room, something is amiss. However, with pink noise this is typical because by its very nature pink noise is random both in frequency and level.

--Ethan

[al2002]

I'll put in a plug for Mackie HR-824s.  I have a pair and they are an absolutely beautiful piece of equipment.  Well built, adjustable and great sounding.  The tightest and most slamming bass I've heard come from such a small box.  And my room sucks, so if you gave them some more space they probably are even more impressive.  What you give up in aesthetics is more than made up for by the sound and build quality.  Plus, amplified speakers are just cool IMO.  Your choice of RCA, phone and XLR inputs is very h ...

I'm a bit late on this thead, but can vouch for the 824s. They are surprisingly good, better IME than most of the small but very expensive  European made monitors that  are liked by audiophiles. Given the built in amps and the fairly reasonable selling price, they are extremely good value.

I have three  for a HT setup. They measure very flat; even in-room each channel  measured within a couple of dB of flat from 80Hz  out to 16kHz. Measured distortion was quite low too, IIRC.

[al2002]

I had a local customer that owns a recording studio bring by a pair of the 8" two way models with the built in amps.

I took some frequency response measurements for him and we adjusted the variable gain to get as accurate of a response as possible.

They were not exactly smooth.

Funny thing is that he bought them thinking that they would be a very uncolored and a neutral speaker to use as playback monitors when mixing.

He was very surprised to see just how colored they really were.

Which speakers are you referring to?

[al2002]

I had a local customer that owns a recording studio bring by a pair of the 8" two way models with the built in amps.

I took some frequency response measurements for him and we adjusted the variable gain to get as accurate of a response as possible.

They were not exactly smooth.

Funny thing is that he bought them thinking that they would be a very uncolored and a neutral speaker to use as playback monitors when mixing.

He was very surprised to see just how colored they really were.

Which speakers are you referring to?

OK. Reading down a few posts I see you meant the Mackie 824s.

I find this very puzzling as all three of my units measured flat with no signs of any sharp peaks or valleys. They sound flat too, with no  obvious colourations that can be attributed to a rough response, even on pink noise.  Just before they went under,  Audio magazne and Studio Sound both reviewed the 824s. Published measurements did not show any evidence of an uneven response.

[Ethan Winer]

Al,

> Published measurements did not show any evidence of an uneven response. <

Yes, these might well be the flattest speakers available at any price, and they also have very low distortion and ringing.

--Ethan

[Danny Richie]

I find this very puzzling as all three of my units measured flat with no signs of any sharp peaks or valleys.

Measured with what?

I did not find them to be too accurate or sound good either. I thought they had a typical poly cone sound to them. It had an 8 inch woofer that was fine for low bass but not suitable for midrange.

[al2002]

I find this very puzzling as all three of my units measured flat with no signs of any sharp peaks or valleys.

Measured with what?

UREI test set , Ivie 30A, B & K and Ivie measurement mikes. The equipment was working well so  measurement errors can pretty much be ruled out. I now have Praxis, but have never felt the need to re-measure the speakers.

Now, how did you measure your samples and what gear did you use?

I did not find them to be too accurate or sound good either. I thought they had a typical poly cone sound to them. It had an 8 inch woofer that was fine for low bass but not suitable for midrange.

Very interesting. As I said earlier,  my three samples sounded uncoloured on broad-band  pink noise, which is pretty good at revealing FR anomalies, and sounded just fine on music and voice. Taking into account the listening sessions and measurements, the accuracy of my 824's  is not in doubt.  Disagree with your comments on 8" drivers. By the way, the Mackies are closer to 9" IIRC.

Had my units measured or sounded as you describe, they would have been back at the vendor's  the next day. Did you measure more than one sample? Seems like you may have had a defective unit.

[Danny Richie]

UREI test set , Ivie 30A, B & K and Ivie measurement mikes.

Did that allow some form of gated time window or did it allow room reflections?

Now, how did you measure your samples and what gear did you use?

I used an industry standard Clio measuring system and the speaker was placed in our anechoic chamber.

Did you measure more than one sample?

I measured a pair of them.

Disagree with your comments on 8" drivers.

That's okay. I don't argue subjective comments.

I stand by mine though. I had a lot of other speakers in our facility at the time to compare them to and didn't feel like the Mackies measured up vary well.

[al2002]

That's okay. I don't argue subjective comments.

I stand by mine though. I had a lot of other speakers in our facility at the time to compare them to and didn't feel like the Mackies measured up vary well.

Fair enough. All three of my samples measure different from yours and similar to each other. Why this is,  I cannot say. Perhaps the US made and Far Eastern produced units are different?

Regarding the Ivie, it is a 30 band RTA good for giving  in room  response. The UREI is an older device, sweep tones, no gating, usable indoors with caution,  best used outdoors.