Test-tone CD

[binkobonko]

Hello,

I have to ask a really stupid question.. I'm not sure how to go about downloading the test tone CD. Am I right in thinking I save the files, then (after perhaps converting them) rip (or burn, even) them to a CD, so I can put them straight in my DVD/CD player, then play each frequency by track? I'm sure it's more complicated than that, but I have had a quick search and found nothing!

I know I could plug my PC straight into my AV receiver, but then I'm not sure how I would set the PC's volume to have minimal effect on setting my receiver to somewhere between 70db and 80db. Or does this actually matter, since with the volume I'm only aiming not to blow my sub anyway?

Does it matter if the test tone comes out my other speakers too? I'm guessing it should do, so do I just decouple them while I'm running the tones?

I ordered a test tone cd from Audio Concepts today, before finding this site. Feel free to tell me I don't really need it!

I have a Radio Shack 4050, the Excel graph, and a brain. I'm sure I can manage this. But please make any explanations extra simple..

Thanks

David

[brucek]

Feel free to tell me I don't really need it!

You don't really need it. Just download the test tones and burn a CD, and play it. You can also just plug the PC into the receivers AUX or CD input. The volume/wave out of the soundcard is set to some appropriate level (0.500) and then adjust the speaker volume with your receiver.

Generally you want to test the sub by itself, and graph that, and then you add the mains and do another measure and graph that. Fairly lengthy process. If you want to shut the mains off, simply disconnect them (with the power off).

To set the volume on the receiver, play a few tones between 50Hz-100Hz and get a feel if you have a huge peak or dip somewhere. Then choose a frequency that you feel is not in a dip or peak, and play it while adjusting the volume of the receiver to set ~75dBSPL on your Radio Shack meter at the listening position. Now don't touch the volume and do all your tones while writing them down or enter them into the excel file.

brucek

[binkobonko]

Hi Bruce, thanks for replying. I've just got a few queries..

You can also just plug the PC into the receivers AUX or CD input. The volume/wave out of the soundcard is set to some appropriate level (0.500) and then adjust the speaker volume with your receiver

I only have a stock soundcard, so I'm plugging into the headphones socket, which is governed by a volume wheel, etc. Probably better to burn that CD, yeah?

Generally you want to test the sub by itself, and graph that, and then you add the mains and do another measure and graph that. Fairly lengthy process. If you want to shut the mains off, simply disconnect them (with the power off).

I probably should have explained, I'm only doing a graph so I can set the parametric EQ on my SB12. I don't need to add the mains for that, right?

Apart from that, I think I understand. Thanks. Kind of wish I knew more about this stuff, but I spend too much time reading reviews!

One last thing, as you're obviously the person to ask? The BFD. With cash, and perseverance, I'm tempted to have a go. However, it would still cost me, I reckon, about $200. Long-term, though, I'd really like to get an Audyssey MultEQ Pro. Second-hand in the UK, they're down to about $1400. Hmm, I was going to ask you whether I should just put the money towards an Audyssey, but now I'm thinking, it really only depends whether I want to have a project in the meantime, so I've just answered my own question..

[brucek]

I only have a stock soundcard, so I'm plugging into the headphones socket, which is governed by a volume wheel, etc. Probably better to burn that CD, yeah?

Any soundcard will have a line-out, which is easily volume controlled by the Windows Mixer.
If you're taking a response measurement using the manual method, then either CD or the PC method will work fine. With the PC, you can use windows media and play the full list of tones one after the other automatically in a playlist.

I probably should have explained, I'm only doing a graph so I can set the parametric EQ on my SB12. I don't need to add the mains for that, right?

Well, you could get the EQ all set up and then when the mains are added you might (very likely) will have a problem at the crossover frequency caused by an interaction between sub and mains causing a dip or peak. This can be removed with the subs phase control. So, you want to do the sub alone and then the sub plus mains from ~15Hz-200Hz for both measures.

Long-term, though, I'd really like to get an Audyssey MultEQ Pro.

Most people who have Auto EQ also require a BFD to set the very low end. Auto EQ doesn't do a great job down to 15Hz....

If you want a worthwhile project, learn how to use REW. It will save you an enormous amount of time and it's far more accurate than the manual method.

Read and become familiar with the REW HELP files and the REW Cabling and Connections Basics.

Also note the REW information Index and the Download Page.


brucek

[binkobonko]

Hi Bruce,

I got some test tones at 1Hz intervals downloaded free from Realtraps.com (great site), mapped out my sub and found a 7-8dB peak at 60hz. Unfortunately, when I set the PEQ on my SB12 to cut it, and did a rerun, it looked almost exactly the same! Heigh-ho. I've written to SVS about it, so let's see what they say.

I'm surprised to hear anyone with a MultiEQ might also need a BFD, given the cost and scope of the MultiEQ. To be honest, I'm not sure my sub goes down to 15Hz, or even 20Hz. I did find it interesting running tones and mapping a graph, so I will read up on REW.

Let's say I get the sub set up well, then map the sub and mains, how do I tell if I have a phase problem? The SVS owner's guide says to listen to a bass loop, like the intro on Godzilla, and have someone adjust the phase control gradually until you hear the most bass. But you're saying I can tell a bass problem from a comparing sub and sub/main graphs?

david

[brucek]

when I set the PEQ on my SB12 to cut it, and did a rerun, it looked almost exactly the same!

To see if it works, set a exaggerated filter on the PEQ (i.e. 50Hz - 20dB) and play a tone at 50Hz and turn the filter on and off.

how do I tell if I have a phase problem?

Do a measure of the sub and mains and observe the crossover area and adjust the phase for the smoothest transition.

Of course, if you run the RTA in REW, you simple adjust the phase while watching the screen dynamically change. Makes it kinda easy.

brucek

[binkobonko]

thanks Bruce

[binkobonko]

Right, I did set an exaggerated cut, and got a massive drop. I've had a fiddle with it, and brought my 60Hz peak down as much as I think is possible. There should be "before" and "after" graphs attached.

I also had a long chat with a guy at my local audio shop. He suggested moving my sub around, and rotating it, before I started fiddling with EQ, to get the best, i.e., loudest sound. He also suggested setting my speakers to large, which contradicts what I've read previously. They're not sats, I've got two old Wharfedale 505.2s for fronts, a Paradigm CC-350 centre and two Axiom QS4 surrounds. I've set my Arcam AVR300 bass management to "large + sub", so all bass frequencies go everywhere. He also suggested trying a lower crossover, between 40Hz and 50Hz, as my speakers aren't tiny sats, but "full range". I have done this, and it does seem to make a difference for the better.

Speaker set up is a nightmare! I'm only really starting to fret now about calibrating my sub because when I picked up my Arcam last weekend, from a guy who was upgrading to the AVR350, he gave me a quick demo. He had B&W M1's and a PV1. The bass from the PV1 was like nothing I've heard from my SB12, a different league of presence, dynamism and tactile feel. Okay, it did cost £950 to my SB12's £500, but still. I asked him whether he'd calibrated it (I thought this might explain its performance). He hadn't. I want my sub to sound a bit more like that - it's not exactly a duffer, right?

I think it's time to venture into REW. I've been reading through the various files, and I think I can work it out. To start with, I'll just try to get a curve, and worry about a BFD later. I've bought the leads I'll need, I just need a soundcard.

I could get a Creative Live 24-bit USB External, or an Audigy 2ZS for my laptop, which I'd prefer. Bearing in mind I want to keep things as simple as possible, and maximise my chances of being able to follow the REW instructions, would a Creative Live be the best choice, or doesn't it matter that much?

Feel free not to address most of the above - I'm only really asking about the soundcard. I'm finding it quite interesting, so far, though.

david

[brucek]

The Creative Live is used by quite a few members here. It's inexpensive and works. It didn't work with Vista until recently and I don't believe it works with Vista 64 bit yet.

brucek

[salvasol]

binkobonko wrote:

He also suggested setting my speakers to large, which contradicts what I've read previously. They're not sats, I've got two old Wharfedale 505.2s for fronts, a Paradigm CC-350 centre and two Axiom QS4 surrounds. I've set my Arcam AVR300 bass management to "large + sub", so all bass frequencies go everywhere. He also suggested trying a lower crossover, between 40Hz and 50Hz, as my speakers aren't tiny sats, but "full range". I have done this, and it does seem to make a difference for the better.

I use the Creative soundcard live 24 and it works fine (I'm using XP).

Even if you asked not to address your comment, I will .

Personally I think is better to use the center and surround speakers as small, but is okay to set the front to large depending on their frequency response, in your case they're okay (that's what I did in my setup, I compared the response between small and large and it was a big difference).

You can play with the crossover, again, using REW showed me that the best crossover was 80Hz.

About the bass management, my Yamaha RXV2700 has three options: Front, Sub and Both. I used REW and compared the response with each option, the best response was setting the sub output to "Sub", so my set up is front speakers "large", all other speakers "small", crossover 80Hz and sub output to "Sub" ...hope this helps