Using test CD to manually input measurement?

[thewire]

I do not have a receiver so I am trying to measure using a test CD of the provided Sine waves on my XA2 DVD player. The player has analog output connected directly to my amplfiers and the subwoofers. I used Windows Media Player to burn an audio CD of the files and I measuring with my Digital RS meter with C-Weighting and Slow response. When I attempt to measure these tones they play at very high levels. Do you recommend that I lower the ouput on my XA2 to do this test? Is this what I am supposed to do? Is there a link to the instructions of how this is done properly and how to import the data into REW? My DVE seems to be having some trouble and will eather change levels sometimes from 89dB to 79dB, or send nothing to the subwoofers even if I try restarting my gear. I did not try ejecting the disc to try again but for now, I would like to try doing these manual measurements while I decide to update the players firmware or not.

For example, when I began to try the CD I started to measure this.

16Hz - 98dB
18Hz - 90db
20Hz- 93dB
22Hz- 98dB
25Hz- 103dB
28Hz- 105dB
31-5Hz- 106dB
36Hz- 107dB
40Hz- 110dB
45Hz- 113dB
50Hz- 116dB
56Hz- 101dB
63Hz- 112dB
71Hz- 114dB


At this point the noise comming from the speakers was going bleeeeehhhh, like a trumbone kind of so I stopped. What am I doing wrong?

[Kal Rubinson]

If you have REW and the RS meter, all you need is a computer to do it right. Sine waves and the SLM will not provide much useful information.

[thewire]

Is there a test CD I can download to set the levels with that is free? Anything similar to AVIA 2 where the crossover can be looked at? My subwoofers do not have a built in crossover and I would like to check this to see that there is no peeks/dips being caused. My copy of DVE has a bass management sweep but I am unsure if this is accurate or not.

[thewire]

I don't see any means of making a different CD without re-encoding anything. I will go ahead and setup like I did previously with AVIA 2 in DVE once I can get the subwoofer to get a signal again. Since I checked this with AVIA 2 prior doing some sort of test while they played simultaniously, If I use the same for DVE I should be in good shape then. If it uses 79dB instead of 89dB now, that will also be also be fine I think. Full bandwidth pans around the room seem correct in DVE. It would have been nice to see it on a measurement.

[Wayne A. Pflughaupt]

For example, when I began to try the CD I started to measure this.

16Hz - 98dB
18Hz - 90db
20Hz- 93dB
22Hz- 98dB
25Hz- 103dB
28Hz- 105dB
31-5Hz- 106dB
36Hz- 107dB
40Hz- 110dB
45Hz- 113dB
50Hz- 116dB
56Hz- 101dB
63Hz- 112dB
71Hz- 114dB


At this point the noise comming from the speakers was going bleeeeehhhh, like a trumbone kind of so I stopped. What am I doing wrong?

Reduce the level. It's way too high.

Regards,
Wayne

[Kal Rubinson]

thewire wrote:

Is there a test CD I can download to set the levels with that is free?

www.realtraps.com and www.rivesaudio.com

But why are you not using REW? Or TrueRTA, at least?

Kal

[thewire]

Wayne A. Pflughaupt wrote:

Reduce the level. It's way too high.

Regards,
Wayne

Thanks. I thought my speakers would explode. That one that was 116dB sounded pretty good actually. The rest, my room was during most of the test noise. Good motivation to finish the room. I will try and using a standard listening level that would be more suitable.

Kal Rubinson wrote:

www.realtraps.com and www.rivesaudio.com

But why are you not using REW? Or TrueRTA, at least?

Kal

I have used REW. I will still continue to use REW with the new laptop (with my external creative USB 24 bit and RS meter). I thought measuring with a CD might be a good exersise. I have not tried TrueRTA on the new computer yet but I have trouble with RPlusD crashing before the program starts. I think it is a Windows Vista 64 bit issue and I don't see the error listed in the help section. Right now I'm not sure what future testing I might also use. I have REW working.

I forgot those were at realtraps. I don't read about those to often. I will consider the CD from Rives also as an option. I will try again using a CD tommorow.

[thewire]

With the test CD from realtraps the pink noise level is 92dB at the lowest setting on all speakers. Can I simply lower each track the same amount of volume before I burn my disc, then test that for the sub+mains integration, or I am stuck using -1dB?

[thewire]

I did this without a CD for now and I don't expect to be able to do so. I moved my front row to near 62% from the front wall, and I turned down the boomy sub in my right corner. I also needed to move my back row which is fine but it means I needed to board over (temporary fix) the rear steps on the riser, and my center back seat is directly against my equipment rack. I had to move the rear subwoofers closer to the corners a couple feet, and I will need to lean over the seats to shut off/turn on equipment. I'm way ahead of myself as far as completion of the room goes, but it sounds much better not sitting in the middle of the room now. I will need to calibrate over again and I might get away with using the BFD now since I sit so much furthur from the subs up front. The noise from them might be inaubible but not sure yet. It is nice now that the rear left and right (placed higher) are now equidistant to my left, center, and right speakers. This is not really the right thread and since I am going off topic, I will leave it at that.

[tonyvdb]

thewire wrote:

With the test CD from realtraps the pink noise level is 92dB at the lowest setting on all speakers. Can I simply lower each track the same amount of volume before I burn my disc, then test that for the sub+mains integration, or I am stuck using -1dB?

Im a little confused as to what you are trying to accomplish here. You said you don't have a receiver? How are you powering your speakers and what kind of speakers are they?

[thewire]

I am powering my 6 Polk Rti70 speakers and my Csi40 center channel using 7 MA-500 amps and a POA-5200 stereo amp. The four THX12 SUB subwoofers are powered. I want to see what happens at the crossover.

[tonyvdb]

without a receiver or preamp your not going to have much in the way of bass management I know your using A BFD but you have no proper level control of the incoming signal thats why your pink noise or frequency tones are so hot from your CD.

[thewire]

I burned it to a DVD-R also as a movie and my XA2 is crossed over at 80Hz. Same level pink noise at 92dB. That is a setting from going from -4 setting on my player to -12. I tested the Shacks disc earlier at reference level but it was a CD.

[thewire]

I will need to do some furthur investigating, but it appears this issue has something to do with the DVD prohibition feature of the XA2.

[thewire]

Test was flawed. moving to subwoofer forum.

[thewire]

Here is a perfect example of the problem I am having with the crossover. This is a RTA 1/24 octive measurement of a boom sounding rumble that appears in the show titled "Lost" over a hundred times. These two subwoofer rumbles are very close together (within a minute) however one sounds like distortion in my subwoofers, the other does not. It sounds like turning off an engine but much softer. Blue is where I do not hear this problem, and green is where I do. The signal being sent to my subwoofers is -15dB low and the level on my subwoofers is raised to account for this. It might be something to do with raising a noise floor? I can't get it to sound good when it looks like this.

[JohnM]

Try using the REW sine wave signal generator and checking the box on the RTA to measure distortion to see if you are getting more distortion on one sub than the other. If you check the "frequency follows cursor" box on the sig gen you can change the frequency by moving the cursor on the graph.

[thewire]

I have not tried the test as I am in a hotel right now and unable to, but the distortion is coming from the subwoofer on the left side of my room. The volume level is slightly higher (emphasis on slight) I think, I have tried switching out subs and I was sure I had put the one in the back of the room doing the same thing, but I have also tried switching out the subwoofer cable and that made no difference as well. The cable I am using was not working for some time very long ago but seems fine now. The distortion noise does not occur if I disable the crossover by setting my speakers to large. Setting the left and right to small only minimizes the issue. Switching out DVD players (Malata n996) helps eliminate the problem (if I remember right) but I am unsure the other player correctly is applying a crossover, because I hear no difference when I change the settings as low as 60Hz. The distortion is very easily heard on a track that is a menu. I cannot hear the distortion with an HD-DVD which had led me to beleave it may have had something to do with DRM on a DVD or the component video upscalling restriction.

[thewire]

I found the cause of the distortion. The reason I could not find the problem was there were two problems. One was a Monster subwoofer interconnect. The second was a headphone jack to RCA interconnect I was using. Now I just need to remeasure and setup my two scenereos of equalization.

Edit: I will have to use these cables for now. Not sure why but switching out cables only worked awhile anyway.

[thewire]

I have an idea. Since I am not using my BFD to equalize my front two subwoofers that play without distortion, I could in theory use that and my extra 4ohm amp to drive the pair (this plays without the higher pitched distortion) in the back, then equalize the roll off response to match the front pair. I will see what I can do.