Anyone knows a pro who can come (Melbourne), measure, try different acoustic panels, and help set them up?

 

It won’t be cheap, but I think it will help a lot. 

I’ve used Red Spade Audio to measure the room and recommend where the improvements need to be.  I then sourced the acoustic panels and installation through Audio Trends.  

@Red Spade Audio  can even supply the panels and is based in Melbourne.

3 minutes ago, Snoopy8 said:

@Red Spade Audio  can even supply the panels and is based in Melbourne.

 

Yes, spot on, I should have mentioned that.  Highly recommended by me, BTW.

Brilliant. Thanks both. I have dropped Paul a line on the website. 

Paul dropped by yesterday and helped out tremendously. From the measurements, we worked out that there is a bass dip in the room, with the current speaker position, and a bass mode around 25hz. We also found the ideal spot for a sub, where the bass response is linear. I moved the JBLs there for now, so that I can have some bass in the music. 

 

It does look like the room requires a bit of treatment to reduce resonance, Paul is working on a plan for us as we speak.  

 

The main thing, and hopefully you guys would have some ideas, is that the soundstage is still shifted to the right side of the room. Without the skill to draw out the room, it is basically 5.5m long, 4.4m wide, the audio setup is on the "dead end" side of the room. However, there is a 2m wide window to the left and a 1.8m wide opening (to the corridor) on the right, near the listening chair; which is right at the back of the room. *standard WAF applies. 

 

Paul advised that treatment and speaker placement wouldn't fix it, and recommended some balance control. So, after he left, I tried and used the Auralic Aries software, and was able to get a centre image with -5db on the right channel. I didn't touch the system after that, as that was the first time I listened to music without a) going mad, and b) constantly standing up and moving the JBLs around. 

 

Problem is, I don't have a balance control on the Phono stage, CDP, and amp. As soon as I switch over to the CDP, the image is back to the right and unbearable (first world problem). 

 

Is there a way to either 1) add a balance control to this setup? can I add an RCA attenuator on the input? or 2) somehow make the room absorption to be balanced? (I assume not, as I am guessing it is the corridor opening that causes the 5db difference?). 

 

From your previous post, it appears that your system consists of Phono stage, CDP, and amp plus JBL speaker in a room that has one side open to a corridor and that you're looking for some way to rebalance the centre image by attenuating the right channel by 5dB, yes?

 

There are plenty of RCA line attenuators in various levels of attenuation on the net and eBay but they are fixed value and require knowledge of amp's input impedance, etc (ie. simple signal level L-Pad, some homework required) - you could also purchase a passive volume control that includes a balance control,  you can buy a simple kit to just add balance adjustment to the existing amplifier, you can purchase a power sink to attach between the amp right channel and speaker  (used extensively in music, electric guitar heads, etc),  plenty of options...

 

if/when you get the balance back in the centre, these non-symetrical (?) room boundaries will still present differences between the 2 channels so this would requite some adjustment of the freq response of each channel so either the old idea of a 10 band parametric eq or the addition of a dsp in your system chain - these can be remarkably successful if used carefully and in moderationbut some homework is required

 

 

Yep. Spot on. Thank you for the knowledge and reply. I bought an rca attenuator to try, $50, why not. I am a bit worried about doing it with a passive preamp due to signal degradation. I can see red gum audio sells a nice one. Also, it looks like there are phono stage that has L/R volume controls. Investigating them as well. 

Jeez, $50!   It's just an RCA line socket and RCA plug with 2 simple basic resistors in between, one in series and the other as shunt

Have a look on the "Instructables Circuits" site - Homemade RCA attenuator - pictures too - check out the inline calculators elsewhere too - suggest you use good quality resistors and RCA ends, not excessive priced or discount parts.

 

Bugger me! I just looked up HiFi Collective and they have some for the 'cheap' price of 40 odd GBP!!!.... 

Another way to look at this is to simply add a couple of power resistors to your speaker terminals - an example, for a 5 dB attenuation of the power to your speaker, just add a 3.5R resistor in series (on line with the signal) and add a 10.3R resistor directly across the 2 speaker terminals - this is a simple "L-Pad" - you can get some decent quality power resistors from places like "SpeakerBug" etc here in Melb - the power resistors from Jaycar, etc aren't suitable.

 

The "downside" of this simple "fix" is that if your speakers require say, 100 watts to achieve satisfactory listening levels, the attenuator power resistors are also going to be high power too

Holy Moly, you are right (I think), its an RCA casing with a resistor inside it. Wow. That's a lot of money for a very little work? 

Found a guide here https://www.instructables.com/Homemade-RCA-Attenuator/ 

And example here, https://rothwellaudio.16.ekm.shop/balanced-in-line-attenuators-3-p.asp 

 

Now I just need someone with maths and soldering iron skills.  

 

 

On 21/1/2022 at 12:14 PM, holliswhy said:

 

The main thing, and hopefully you guys would have some ideas, is that the soundstage is still shifted to the right side of the room. Without the skill to draw out the room, it is basically 5.5m long, 4.4m wide, the audio setup is on the "dead end" side of the room. 

 

 

I have a similar (I think) issue. My room is rectangular and almost perfectly symmetrically set up. The only difference is a door back on the left wall (behind the listening position). My balance is shifted to the right by 2.3dB. I’ve looked at everything trying to figure this out, even doubted my own hearing. I think it may come down to the fact that the wall on the right is an external one, with a brick wall on the outside, whereas the left wall is a lightweight internal wall, i.e. just timber frame and plasterboard. I’ve resigned myself to controlling the balance in the player software via AU plugin, or on the TVC which has separate volume dials for left and right.

Always challenge the design assumptions made by an audio consultant looking at your room.

 

What are the reverb and decay times they are chasing?

What is the purpose of your room? HT or stereo? 

 

I've had multiple consultants look at my room in the past and I have had up to 80 panels suggested, when 21 were subsequently deployed to a very good outcome. 

Two resistors, but who's arguing - I see these Rothwell units are 79GBP, not 40!!!  Crazy markups.   Most of these are set at 10dB, 20 B or more, but rarely at your required 5dB 

 

To test this out, just pop into your local Jaycar and get the single phono plug and the similar socket, and the resistors -  5, maybe $10 for parts - don't get fancy bits yet, maybe later.

 

The value of the resistors are dependent on the input resistance of the amplifier of the "unbalanced inputs", that require the RCA plugs/sockets - this is clearly specified in the amp's operating instructions.

 

What area are you from in Melb?

@Steffen I thought I was going insane as well, so it was good to get a pro to tell me that I am not that weird  I wish I knew, as I would have gotten an amp with balance built in. 

 

@HdBI have asked Geoff of Aurealis audio to help out, he is asking me the same questions (RE: input resistance). I am in Mount Waverley. 

Well how about that, so am I!!  Send me a pm (and maybephone no) and we'll assemble one of these units fairly easily and you can try ot out tonight

oh, what is your amp's input impedance, by the way?   Or the model of amplifier?

@HdB PM coming. 

I assume you're using the RCA unbalanced plugs so no problem -   So,  amp input load is 22k so 5dB resistors are 9k56 and 28k3 - will pick the Beyschlagg ones up in the morning (best for amp) and be ready for pickup tomorrow night, okay?

On 24/01/2022 at 10:38 PM, holliswhy said:

I thought I was going insane as well, so it was good to get a pro to tell me that I am not that weird  I wish I knew, as I would have gotten an amp with balance built in. 

My room is very asymmetrical and the balance changes with the listening volume! A balance control for my new preamp was a must as rebuilding the house wasn't going to happen.

@HdB Really nice to meet you last Friday and a massive thank you for your help and effort in building the XLR attenuator for me. 

 

It has been quite interesting, after applying the attenuator, the same effect occurred as the streamer/ its digital DSP. The vocal is centred and gained a lot of realism and body. It sounds like the singer's vocal has a depth and detail that I haven't heard before. Also, the soundstage now fills, quite evenly across the entire room and doesn't cuddle together in the right side corner. Very importantly, as well, the bass note is now in the middle, rushing out from behind the singer. 

 

As @HdB and I discussed last week, Vitus Audio probably expects its owners to have a dedicated room and thus never bothered or thought about situations like mine. But we did find it interesting that, given it is just software, for them to not implement it. I suspect it shouldn't have impact on the sound? Surely, having a balance control to get a centre image should improve the sound quality than having an extra thing in the amp?

 

Some say, with audio, it takes up to ten years before you start to know what's a good sound and how to achieve it. It has been ten years for me now, and I don't think I am anywhere near that level of knowledge and experience. I guess I need to go out more! 

 

Thanks again @HdB for helping out and @Paul Spencer for dropping by and imparting your skills and knowlege on the setup. Without our appointment, I don't think we would have resolved it!

 

@HdB too busy listening to the CDP on XLR before trying the RCA attenuator! 

Give me another week.  

Not a problem, simple solution, good bit of fun - I think a later exam of Paul's room test results might enable further refinement of the room's acoustics now that the balance problem is resolved.

 

If anyone else has a similar problem .... 

 

We're all learning, sometimes quickly, sometimes slowly and as we get older, I think our perception of reproduction changes too so ...

 

Discussions about room acoustics seems to be a foreign language to many hifi enthusiasts but the concepts/rules are pretty straight-forward to understand once you start with the basics.  Combining these with careful use of a dsp can achieve excellent results without resorting to expensive equipment upgrades, particularly speakers.