Order of Importance with setup?

[Vaughan Odendaa]

Gee, thank you for your comments, Sploo. Really appreciate it. Sorry if I'm "slow". I don't mean to act like a dolt or anything but I usually take a bit more time to understand things properly and so I need reassurance that I know what to do.

Thanks again.

--Sincerely,

 

[Vaughan Odendaa]

Sploo, one more question to you. Sorry if this has been asked before. But to test my sound card to see if everything is right, what kind of cables do I need ? Do I need two seperate split left and right into two 3.5 mm jack ?

Because I need to connect the front out with the line in so I think I might need a seperate left and right going into one 3.5 mm jack or into 2 3.5 mm jacks since the output needs to be connected to the input.

Do you even get a left and right into 2 3.5 mm jacks, or would I need two left and right split 3.5 mm cables to connect to both ?

Thanks for your comments.

--Sincerely,

 

[sploo]

Sploo, one more question to you. Sorry if this has been asked before. But to test my sound card to see if everything is right, what kind of cables do I need ? Do I need two seperate split left and right into two 3.5 mm jack ?

Erm... I think you've already asked and I've already answered.

I'm assuming you've got some form of amp (2 channel or AV receiver) and it'll have RCA (phono) inputs. Therefore you need one of the jack to dual RCA leads.

Whilst you can get a mono 3.5mm jack, generally they're all stereo (the same as the plugs on headphones for most personal CD players/iPods). Think about it - you've got a lead with a 3.5mm jack on one end, and the cable is split to give you the left and right signals at the other. In the case of headphones, there's speakers at one end, in the case of the jack to RCA lead, there's RCA plugs.

Because I need to connect the front out with the line in so I think I might need a seperate left and right going into one 3.5 mm jack or into 2 3.5 mm jacks since the output needs to be connected to the input.

Do you even get a left and right into 2 3.5 mm jacks, or would I need two left and right split 3.5 mm cables to connect to both ?

I think you need to re-read the instructions I posted - the cable connections stated in post #37 give you everything you need.

Draw it out on a piece of paper if you don't have the leads.

 

[Vaughan Odendaa]

Sploo, thank you for your suggestions.

You know, over the last few days, I've been trying to find the right connectors. I just bought two duel RCA to 3.5 mm minijack connectors and the connectors are far too wide. Both my line in and front out connections are side by side. There is simply no way that I can get both of them in.

My salesmen then told me that they have longer jacks, so I went and found that they still were too wide. They fit in, but only one of these jacks can fit in. So frustrating. The guy then told me that there was nothing he could do for me and that he didn't know what I could do to sort out the problem.

I almost gave up. Luckily, there was a computer shop next by so the guy just recommended that I get some cables, rather than a connector. He is making me a duel RCA female jack to 3.5 mm. So I'll just plug the male cables into the female duel RCA.

Much, much easier. The other connectors I've got. But thank you for all the suggestions and the advice. I really appreciate it.

Thanks.

--Sincerely,

 

[Vaughan Odendaa]

Okay. I first tried to hook up my two RCA cables to my front out and then from there, to the Auxillary in left and right. I wanted to get sound from PC to hifi.

I get no sound. I can hear that my hometheater speakers are buzzing when I touch the RCA leads so something is there. But I can't hear music playing when I play a music cd.

Have I done something wrong ? I'm just testing to see that the connections are working. I have a Yamaha RXV-450 amp.

--Sincerely,

 

[Vaughan Odendaa]

Alright. I got sound. All this time I've been using the front "left and right". No sound whatsoever to my hifi to aux in. So I tried using the "rear out" as a techician advised.

I got sound ! So now when I use ETF, I need to use the "rear" out and line in, not the front out ?

And I went through the ETF help file but it isn't specific enough. If you just want to take a low frequency measurement of your room, what or why would you need to use linear responses, impulse responses, etc,etc ?

I don't know. For me, I am most interested in taking frequency response measurements down low (from about 300 hz down to 20hz). To me that is most important.

So what do I need to do ? Also, is there any way of getting a decent looking display on ETF ? I looked at RTA and the graphics look more pleasing to me.

I know, I know, I'm nitpicking. Help would be appreciated.

--Sincerely,

 

[Ethan Winer]

Vaughan,

> when I use ETF, I need to use the "rear" out and line in, not the front out ? <

That makes no sense to me. Are the "front" and "rear" labels centered between the jacks such that you might be misreading the labels?

> If you just want to take a low frequency measurement of your room, what or why would you need to use linear responses, impulse responses, etc,etc ? <

What matters most for your "range of interest" from 20 Hz through 300 Hz are the raw response (at a high resolution, NOT third octave) and the waterfall graphs that show modal ringing.

--Ethan

 

[Vaughan Odendaa]

Hi Ethan,

I did not misread. The labels are clear. The top label is line in, followed by front out, then rear out, then LFE out/center " ".

If I connect my RCA connector to front out and loop it to the auxillary in on my Yamaha amp, there is no sound. Whatsoever. The card is functioning properly. But when I connect to the rear out, I get sound. This is just as the PC techician recommended.

I also had to go to the control panel and set the speakers (in advanced section) to 5.1 speaker system. Previously it was set to desktop speakers.

So my question now is: since I get sound from the rear out (stereo), do I use rear out for ETF and obviously line in ?

--Sincerely,

 

[Vaughan Odendaa]

Just to follow up on my previous post, does it really matter whether I use front out or rear out ? Because I am still getting a stereo signal through the speakers which I assume is what I need.

Am I correct ?

--Sincerely,

 

[sploo]

I'd guess so, yes. It is very odd that you're getting the sound from the rear outputs.

Try running ETF and getting it to generate a sweep. If you hear the sound then I see no reason why it shouldn't work.

It's been quite a while since I used ETF, but if I remember right, it shows you the input level (so you can trim the output volume/input sensitivity). This should help you check that it's going to work.

BTW You will need to turn your amp up pretty loud. When I first used ETF I was getting some stange results, mainly because I was only driving my amp to around 60dB, which wasn't loud enough for the RS SPL meter to get decent readings.

I got good results with the amp knocking out around 80-90dB, but found that ear plugs made it a bit more comfortable!

 

[Vaughan Odendaa]

Sploo, just a question. Do you still use ETF as your software of choice or do you use other software ?

I watched the videos for the software but Doug wasn't specific enough for my liking. He doesn't go indepth on what the certain functions are or why you need or should need to use them.

I must admit, I also find it strange that the front out's don't get sound. Have no idea. I'll use the rear out's and report back, hopefully with some measurements.

Also, another thing. I just messed around with the ETF software for a few seconds and went to calibration of SPL meter. I loaded the correction file that Doug recommended (at Home Theater Shack), and it tells me that the meter has been calibrated. But then when I analyse and press "ok", it tells me "error 3462" or thereabout and it says microphone calibration format error.

Anyone thoughts on this ?

--Sincerely,

 

[Ethan Winer]

Vaughan,

> I also had to go to the control panel and set the speakers (in advanced section) to 5.1 speaker system. Previously it was set to desktop speakers. <

Maybe if you set it to "desktop" it would then come out the front?

> since I get sound from the rear out (stereo), do I use rear out for ETF and obviously line in ? <

I guess so. You'll just have to try it and see what happens.

--Ethan

 

[sploo]

Sploo, just a question. Do you still use ETF as your software of choice or do you use other software ?

I watched the videos for the software but Doug wasn't specific enough for my liking. He doesn't go indepth on what the certain functions are or why you need or should need to use them.

I must admit, I also find it strange that the front out's don't get sound. Have no idea. I'll use the rear out's and report back, hopefully with some measurements.

Also, another thing. I just messed around with the ETF software for a few seconds and went to calibration of SPL meter. I loaded the correction file that Doug recommended (at Home Theater Shack), and it tells me that the meter has been calibrated. But then when I analyse and press "ok", it tells me "error 3462" or thereabout and it says microphone calibration format error.

Anyone thoughts on this ?

--Sincerely,

I set up my room, and haven't had the need (or time) to do anything since. However, I would see what the latest version of ETF looked like if I was going to do it again.

Once you've taken a sweep measurement (I'd recommend the full range, not just low frequencies) you can tell a lot from the frequency response, ringing time (the 3D graph) and impulse displays.

If/once you've got those, you should be able to use the Print Screen (Prnt Scrn?) key on your keyboard to take a copy of the display, then paste it into an image program like Paint Shop Pro. You could then post them here and I'm sure myself, Ethan, or one of the other people familiar with ETK would be able to give you some recommendations*.

* The recommendation will be - go to realtraps or GIK and buy some panels. And they'll be right

 

[Vaughan Odendaa]

Alright. First, I want to apologize because I mistook the rear out for the front out. Pretty embarrassed about that. The labels were not that clear.

So everything is working as it should. Now, the problems. I have connected up the right input to the right output and the left " " ". Just to test the sound card.

I followed the instructions from the ETF help file. I used my windows mixer to set levels. Now I have done a test and the measurements don't look clean. They have a bit of fuzz around the flat line.

This is with 44 khz and 48 khz. Now before you see the graph there are two windows where you get to see the levels. The right channel is never exactly straight. There is a bit of fuzz. The left channel is straight, sometimes.

I cannot get the right levels to be identical to the left. But what I am worried about is that I can't get a clean read out. And if I choose the 48 khz sampling which ETF recommends, the graph is still not how it looks in the "good measurement section" in the help file. It looks kind of like the bad measurement.

What I think I'm going to do is post some of the graphs to you and be a bit more specific on what my mixer levels are set to. I've been the better part of six hours trying to get a clean graph. Remember, I'm just testing my sound card as ETF recommends. I haven't done any room testing yet.

Please help me out.

--Sincerely,

 

[Vaughan Odendaa]

I managed to get the left and right card levels to within + - 1 dB. Sometimes slightly more. But the results are still not clean. There is still noise.

This is with either 44 khz or 48 khz sampling. They give almost identical read outs.

Is there something that I'm missing ?

Thanks.

--Sincerely,

 

[Vaughan Odendaa]

Could someone please tell me how to send attachments ? I would like to attach a zip file with measurements I've made.

Thanks.

--Sincerely,

 

[sploo]

When you start a reply, scroll down to "Additional Options", then click on the "Manage Attachments" button. Note the maximum allowed file sizes.

 

[Vaughan Odendaa]

Here are a few pictures :

First picture is just showing the levels of the left and right card

http://img470.imageshack.us/img470/9177/channellevellargewn2.th.png

Now you can see the FR graph. Notice the noise around the flat line. It doesn't look clean :

http://img427.imageshack.us/my.php?image=graph144khzsamplinglargeuc6.png

This graph was taken using 44 khz sampling.

Here is an identical graph but using 48 khz sampling :

http://img289.imageshack.us/img289/6088/graph248khzsamplinglargeev1.th.png

Same problem. I am also going to post the impulse response graphs for both 44 khz and 48 khz sampling.

44 khz sampling impulse response :

http://img194.imageshack.us/img194/905/graph1impluseresponse44khzsamplinglargeud4.th.png

48 khz sampling impulse response :

http://img436.imageshack.us/my.php?image=graph2impluseresponse48khzsamplinglargedk8.png

So there you go. Please tell me what you think. Would actual room measurements be affected by this ? What are your thoughts on the "poor measurments" ?

Thanks.

--Sincerely,

 

[sploo]

Imageshack doesn't seem to want to display most of the pics right now, but I did get to see the first couple.

To be honest, they're good. Suspiciously good.

If you look at the readings I took (http://spikyfish.com/acoustics/) you'll see that the first one showed heavy reflections from the walls, floor and ceiling.

As I added absorption, it reduced the reflections, but still left some. Admittedly, the room is long and thin, so the speakers are working in a sort of 'tunnel' - i.e. lots of reflections as they're close to the side walls. However, even in a big room, the impulse responses you've posted do look very good.

Where are your speakers in relation to the side walls?

 

[Vaughan Odendaa]

Sploo, these measurements that I took were sound card only. I repeat, I only took sound card measurements.

This whole time I've been struggling to get a good flat line with no or little noise. I just basically took the left line in to line out and right in to " " to do a simple loop thru.

What do you think of the graphs based on the fact that it's sound card only ? Looking in the ETF helpfile, it shows a good sound card measurement and mine are certainly not. And if I choose a higher sampling, it doesn't improve matters much at all.

Hence my dilemma. I may buy another card. I just spoke to the salesmen who I bought the card from (remember, this card is only R120, about $18 in your currency). They are willing to do a swop. The card I might be replacing is the Sound Blaster Live Value 5.1.

This card is 2.5 times the price. I just want confirm that it is the sound card's problem. I would hate to buy another card and for the same problems to happen.

Your advice would be appreciated.

--Sincerely,