Here goes nothing... the J blog

Almost the final piece in the puzzle... Yesterday I fitted the slat wall at the first reflection area of the L speaker.



In an ideal world I'd have a perfectly symmetrical arrangement with the same layout on left and right. However, domestic environments are rarely ideal. The shelves, vinyl and hifi on the right is doing a good job of breaking up the 1st reflections of the R speaker. The left is more problematic - without the slat wall there was a slight shift of the centre image to the left and information from the left channel seemed a little more 'smeared' and less focussed and 'carved' into space. Ideally, more shelves would've worked well, but we simply didn't want to narrow the room further and it may have felt a little cluttered.

Instead, I opted for a walnut veneered slat wall. It compromises 10mm acoustic felt and 11mm deep slats on top. This should add some diffusion and absorption. It is only thin, but should help a little around the mid range and high frequency.

I took measurements of the RT60 decay time (at listening position) before and after.

This is DT60 decay before:



Decay time is generally 400-600ms from 80Hz to 10kHz. It is mostly above 500ms from 200Hz to 2Khz. Ideally, I'd like it to be below 500ms throughout. This is a reasonable decay time for a reasonably spatious room. Too high a decay time and too much echo. Too low a decay time and it can sound sterile and over damped.

This is the decay time with the slat wall:

I was pleased to see that there is a measureable difference! In general, a 10-20% reduction in decay time. Pretty much around or below 500ms from 80Hz to 10khz.

So, did it sound different? This is obviously highly subjective, but I am pretty sure there is a noticeable difference. There is more focus and instruments just sound more tonaly 'right'. The soundstage is slightly more organised and instruments have the impression that they are more located. TBF, it was pretty good before, but things have just got that little bit better. Strangely, music sounds about one notch (a couple of db) quieter... I wasn't expecting this, but assume it is because I am getting less reflected sound.

All in all very positive and worth doing.

I am excited too... the room is ready and the house is virtually in a state to welcome guests. Two people are coming to have a listen in a few weeks - can't wait! It'll be great to catch up with folk, drink tea/coffee, eat cake and enjoy some tunes. We may even listen to a few different amps too!

Edit: The Rockwool looks a little conspicuous atm, this will be covered in dark blue fabric soon. I'm also keen to measure with and without the bass traps.

Beauty! Really coming on. I certainly found that much experimentation was required with acoustic treatment. I often did not get expected results and just had to try various things until I found something that actually made a positive difference without a downside. But you've got the tools and mentality to get you there better than most of us.

Thanks Chris. If I'm honest, this room hasn't required much skill to get right. Fortunately, it tested pretty well from the outset, so the treatments and tweaking are the icing on the cake. Although changes have been small, they have been extremely valuable to increase my understanding of how certain treatments (bass traps, absorption, diffusion etc.) and adjustments (speaker toe in, tilt etc.) effect the measured and perceived performance.

The main aim has been to achieve a good sounding room whilst creating an attractive domestic environment. The room is dual purpose, so my wife and I were aiming for something acceptable as a living room and a music room.

Well, that is an interesting twist...  The top enclosure of my Vaders is now driven by a class D Purifi amp, I had not expected that!  It is certainly bringing a smile to my face and providing a decent upgrade.  It will remain in my system until a better (and affordable) option presents itself.

Full report of the listening experience and the bake off here: audioaddictsforum.com/post/91562/thread

Take a digital source?

It would not be rude at all... Bring your source (and DAC if required - mine is very basic! ). Bring as many CDs as you want. You'll know exactly where you are with your own source too. My system is very much fine tuned for Vibyl, so I can't guarantee how it will sound.

Before anyone thinks I am being awkward I have a problem with vinyl due to tinitus which makes listening to vinyl very uncomfortable for even very short periods . Will have a good think and then PM Jason and see how he feels .

The house renovations are (finally) nearing an end, so I can now start to focus back onto hifi, music and speakers. It's been nearly 8 months since my last post and I'm looking forward to continuing the journey.

Quite a lot has happened in my hifi world since the last post, so it is probably wise to get things up to date first:

The Purifi power amp is still in the system and nothing better has (yet) presented itself, although I do hope to hear some more alternatives in the Autumn. TBH the Purifi does nothing wrong in my system/room, so I'm not really sure what will better it, but I'm all ears! One amp that will (almost definitely) better it is something based on the latest Purifi 1ET9040BA amp modules. These are likely to be rather special, so are certainly on my radar for something to try. Lower distortion, more power and better SNR, what's not to like?! A uber amp may be on the horizon....

My seating position is probably the biggest change to report since my last post! This sounds trivial, but to me it has been anything but. The room is about 6.9m long and the speakers fire down the room. Most room layout/acoustics wisdom would place the listening position some way forward of the rear wall (the wall behind the listening position). The room is long, so I had the luxury of sitting well into the room and not being too close to the speakers. Room modes are much more prominent and powerful near boundaries and corners, so it isn't ideal to site the listener there unless absolutely necessary. I spent the first 3-4 months measuring and setting up my speakers to listen about 2/3 of the way down the room. This was how it was set up when Steve and Oli listened early on.

Sometimes during listening sessions I would move to stand or crouch at the back of the room... I shouldn't like it here but I did! Yes, the bass was too pronounced (due to boundary reinforcement) but the sound was more effortless, more realistic and less 'hifi'. Some people like their hifi to be super resolved and clean, but that is not my preference. I want to hear as much detail as possible, and want to hear deep into the recording space, BUT not at the expense of a natural and realistic tone and timbre. This is obviously highly subjective, but in my room I can hear the presentation and tonality change as I move back and forth.

I moved the mic to the back of the room measured and proceeded to retune the Vaders to this aft listening position. Initial measurements did indeed show that the boundary reinforcement was very high in this region. I had strong reinforcement at 26Hz and around 40Hz. 40Hz definitely needed taming as it was way to prominent in a lot of music. 26Hz is less prevalent in most muisc, but still needing dialing back to increase transparency - I didn't want excessive bass colouring the mids and HF.

After a retuning session I sat back and spent my first few listening sessions on the comfy sofas at the rear of the room. Wonderful! This was really hitting the spot (pun intended!). The music just seemed more natural and effortless. It's like the music had more time and space to become free of the speakers. The image seemed wider and deeper and everything had a little less urgency and flowed more naturally.

Here are the measurements and tunings from an early tuning session. (things have changed a little since then, more on tunings to come):



The green line is the frequency response without tuning and the orange and blue are two tunings with a smoother bass response.

I shouldn't really be sitting right at the back unless I had to, but for me it worked! Perhaps because the speaker's bass is tuneable I can reduce the effects of the boundary reinforcement. Another issue with sitting in front of a boundary is early reflections, these can cause timing issues and smear sounds a little. There is usually a reduction is clarity. There is a window behind me, so this was partly countered with some heavy, lined curtains. I have also added 3 large plants around the listening area to act as natural diffusers.

The change in listening position happened back in Dec 2023 and I have been there ever since. I occasionally move forward when curiosity strikes.... It doesn't sound bad at all, but it ain't my preference - the aft position seems more natural. I no longer sit dead centre and the aft position seems to allow off axis listening without any reduction in musical pleasure - this is ideal when a multiple people are listening.

Another advantage of sitting further aft is that I can use the boundary reinforcement to reduce the load on the plate amps driving the 12" bass drivers. The room is assisting 26Hz and 40Hz massively, so these frequencies can be backed off quite a lot on the bass tuning. Reducing load at these lower frequencies will greatly increase headroom and can only help the plate amps.

Chris, Steve, my brother and various other friends (into hifi) have visited and sampled the fore and aft positions. Consensus seems to be for the more relaxed and natural aft position.

I shall post more soon. I still need to document my battles with tuning the bass - flat measuring bass is definitely NOT always what sounds best to my ears. Later tuning of the speakers has become a more time consuming hybrid and measurements and weeks of listening and tweaking. A true labour of love, but I love it and the results I am hearing.

One of the final stages (coming soon) will be the fitting of the absorption canvasses around the aft listening area. IMO the rear area of the room is still a little too reflective. I want to continue my ethos of stealth treatments, so shall be placing absorption materials inside canvases of our photos. More of this in coming months.

Very interesting, Jason.
And congrats on getting your new room completed.

Optimum listening position is an interesting conundrum.

With a friend's system with recent Quad electrostatics I preferred to sit way off axis. The sonics somehow jelled in a way they didn't on axis. A more relaxing and involving listen imo.

My own preference is invariably to listen across the width of the room. So in my rectangular room (12×20 feet) I don't have much in the way of distance to play with.
It is intriguing, though.

Also interesting to see an approximately 10db drop in level from low to high frequencies.
How was that determined? By listening or some kind of predetermined method?
That does tie in with my own subjective preferences.

Another friend has carefully tuned the frequency response of his system to be perfectly flat. No lumps and bumps, and no roll off, it's horizontal flat ..... and wincingly bright to my ears! He loves it, so fair enough.

If you take a traditional box/cone loudspeaker that has a flat anechoic response and good on an off axis dispersion, and stick it in a room, you'll get around a 10dB drop from low bass to high treble.

That balance is what most people prefer according to controlled testing.

Flat response in room does sound very toppy, but some people do like  it like that.

Regarding listening positions, my room is very similar to Jason's in size and shape, I also prefer to listen seated near to boundary, either at the far end against back wall or roughly half way down against side wall (off axis). I like the slight increase in bass that gives.

Due to the large volume of the room there's never any issue with bass boom even if you sit in a corner. On the flip side bass probably does not go low enough with enough power for some. Personally I like deep bass but not to the extent where the kick drum impact starts to dominate and that's all you end up focussing on. Even if that probably is more accurate.

Not surprised, your speakers go significantly lower in frequency and at a much higher amplitude than mine. What I have works, albeit more by happy accident than design

Which bit of the 'SERENE' is this you are testing Jason?

Back in my long gone vinyl days I had an ongoing curiosity with record clamps.
I came to the conclusion that it was mainly about mass, the more mass the better the sound.
A 1kg weight sounded amazing 👌 but would probably have b#ggered the bearings quite rapidly.

Maybe a 1kg weight would be even better?
Try it if you can mock something up, I'd be very interested what you think.
It wasn't subtle ime.