Considering a purchase kemper unpowered head

v8 speaks the truth ?

Welcome CC

Quote from ChainsawCharlie

the main thing that's holding me back now is knowing what output is going to sound the best, that wont need to be cranked up so as to annoy the neighbours but, also to appreciate what the Kemper can provide

KPA's outputs are all linear, so they sound the same as each other and regardless the output level as long as you stay in your chain's linear window.

The main differences you hear when changing volume on a linear system is due to how our ears perceive the same sound at different volumes: hardware is not generating a different tone, apart from room's resonances, reflections, interactions

Quote from ChainsawCharlie

do most users have a Cab for home use?

I use linear cabs (monitors), sold everything strictly guitar-related long ago :p

Quote from Wheresthedug

my advice is don’t overspend on the speakers and used the money saved for some acoustic treatment in your studio. A bit of decent treatment Will make much more difference than several hundred pounds extra on the equipment budget.

While I generally agree with the concept, the main issue in a normal room are low frequencies resonances, something that is not affected by normal absorbing panels and that is quite expensive to fix
Saving 200 € on monitors to be invested on room treatment is not going to solve the lows mud, sadly.

Much more effective (and cheap) IME is - if a computer is used - to invest in digital room correction software, provided the listening point is steady and consistent.

Quote from pippopluto

While I generally agree with the concept, the main issue in a normal room are low frequencies resonances, something that is not affected by normal absorbing panels and that is quite expensive to fix

Saving 200 € on monitors to be invested on room treatment is not going to solve the lows mud, sadly.

I totally agree, low frequencies become more of an issue the smaller the room so treated tales up a much higher proportion of available space too which is a Catch 22 scenario.

I wouldn’t waste a lot of money on commercial treatment products as the data shows most perform little better than the good old industry standard of OC703 (if you are in the US) or Rockwool RWA45 (if you are in the UK like me). However, a lot can be done very cheaply with DIY treatments and a decent book like Rod Gervais Home Studios Build It Like The Pros.

OC703 or RWA45 provides effectives 100% absorption down to around 250hz. It falls off after this but even a singe 100mm deep panel still has an absorption coefficient of around 0.85 at 125hz. Thick panels and panels placed with an air gap between them and the wall provide decent performance down to the bottom of the guitar range.

A budget of £200 would by around 50 sheets of 2400 x 1200 x 100mm RWA45 in the UK at the moment. Make some cheap frames to hold is and cover them with the cheapest curtain lining material you can find (costs next to nothing). That provides a lot of treatment for very limited budget.

of course where you place the treatment matters a lot. Covering all surfaces with a single sheet of 100mm thick will yield VERY different (and certainly unpleasant ?) results than covering a limited number of points (completely filling the corners) with very thick panels. Triangular “superchunks” as deep as you can manage in all four vertical corners will provide a significant improvement at lower frequencies. Adding in the vertical corners where possible (wall to ceiling and/or wall to floor) will also make a substantial difference. The downside is the space it takes up.

If I understand correctly room correction software only deals with the frequency domain issues but not time domain like phasing.

I haven’t used room correction software like Sonarwoks etc but I tend to see them in the same category os using a noise gate so “solve” an earth loop in a guitar rig. Better to treat the problem at source first rather than cover it with a sticking plaster. However, once all reasonable steps have been taken to eliminate the source Then such solutions can make a good sound better. Sound on Sound summed it up in their overview of room correction software “ So, as ever with ‘magic bullets’, they’re not perfect. Used in conjunction with proper acoustic treatment, however, then can certainly help to wring the last few drops of performance out of your monitoring system.”

It is always best to seek forgiveness than ask permission ?

Quote from ChainsawCharlie

...if I did all of this to my man cave/ bedroom

But in my expericence bedrooms are typically not so bad for this. Better than hallways, offices, large living rooms etc. - in your bedroom a lot of frequencies will be absorbed already by bed, clothing etc. which might solve any issues with the low end easier. Careful with the highs. If these are totally sucked up by the room you will tend to put too many while tweaking. Nevertheless you will need to learn anyways about the room and how it sounds and where hot spots for some frequencies are.

ouch! That sounds like what our old engineer used to call a “hostile sound environment” ?

Quote from ChainsawCharlie

how safe are 2nd hand kemper toasters unpowered and remotes?

close to bullet proof. If they are working at all you should be all good.

Quote from Wheresthedug

low frequencies become more of an issue the smaller the room

Well, let's say they are centred to higher freqs the smaller a single wall-to-wall dimension is, regardless the room's size. If a room is 6x3x3 it can be a nightmare much more than a 5x3x2.70 because multiple lengths share resonance modes, and because the higher the number of dimensions of the same size the more that specific resonance mode multiply itself.

The first resonating mode over a length (wall to wall) of 10 meters is 17 Hz @ 21° C, and becomes 34 Hz over 5 meters and 86 over 2 meters so they enter more the audible freqs range; nevertheless, a stationary wave of 30 Hz is definitely annoying! And, there are the secondary modes that are definitely audible at relatively high SPLs so you can have resonances in listening range even in relatively large rooms.

As for more directional freqs, such as 250-500 Hz, I'd not advise about damping them as much as possible: a music room requires some vividness, and the more directional the frequency, the more it should be dumped at the spots of first reflection.

Furthermore, the really nasty reflections that should be treated the foremost are the ones taking place in the first 10 ms (for example because of desk reflection, the rear wall in case the listening position is close to it, the front wall in case the cabs are close to it).

Then, it depends on the surface: having a window/glass door in a spot of first reflection makes things harder to fix, since it's not always possible to install curtains (and you need acoustic fabric anyway, forget that any cotton/wool will dump 300 Hz! In fact, cabs' fronts are usually covered but that doesn't affect the sound in any way).

Buying assorted absorbing material and placing it here and there won't generally return a great room sound, this requires a certain amount of comprehension of what's going on in that room and a vision of how we'd like it to sound.

The first three resonance modes are an exception, as they'd better be dumped as much as possible. As I was trying to convey, a good room treatment (including labour) is hardly going to cost as low as 200 €.

Quote from Wheresthedug

If I understand correctly room correction software only deals with the frequency domain issues but not time domain like phasing.

No, this is not the case - at least for the state of art. Modern DSPs are able to detect phase shifting as well.

Quote from Wheresthedug

I haven’t used room correction software like Sonarwoks etc but I tend to see them in the same category os using a noise gate so “solve” an earth loop in a guitar rig. Better to treat the problem at source first rather than cover it with a sticking plaster

This line of reasoning is irreproachable, if you have money and knowledge! But, on the same rigorous line, a real "at the source" treatment would require the room's walls and doors/windows to be designed from scratch for the best sonic results; this would proportionally be more expensive than treating the room as much as treatment is more expensive than DRC.

My premise was that 200 € of treatment won't solve an average room (unless you know what you do and do everything by yourself, including designing, creating and installing panels and bass traps), so I'd spend that money in order to make sure monitors are properly placed with respect to the room, the desk and the listening point (including dumping their own resonances with their support base), to buy a measurement mic (100 €), and good DRC software.

You can try one (I'd advise about Foobar2000 as a player and the free plugin RoomEQ by MathAudio): once you do, you'll not want to uninstall it any more; and you'll know what to do with SoS' generalist advises

The only issue with DRC is that it's dependent on the listening spot, so you have three options:

elect a spot (like in a homestudio); elect a larger spot (such as a whole couch in a living room), where correction will be averaged all along it; or save a preset for each of the places you listen from (in my studio those would be the PC chair and the office desk). You can of course correct a well-defined spot and then a larger one as different presets.

One interesting sub-product of the application of DRC is that it corrects the whole audio system, from audio gear to your ears. So it will linearise the cabs as well (which are always less linear than say an amp); this implies that a mediocre pair of cabs will sound much better, but the measurement (and a given preset) irreversibly links that audio system, its placement, that room/furniture/windows/panels, and the listening spot.

Basically, you'll have to measure and correct again if any of the above ever changes. It only takes a few minutes tho

We are going off course into much more detail than the OP was seeking.

I actually agree with what you are saying. Particularly things such as as the modal issues and the fact that you don't want to make a music room dead or too dull. Also, a basic plan and some knowledge is required, but there are plenty of good resources available to help with that. Some are pretty accessible like the Rod Gervaise book etc. Some are much more of a heavy read like Philip Newell's book or the Alton Everest Masters Handbook of Acoustics. But starting with some basic room treatment is definitely the way I would go in the first instance. I would consider tweaking it with DRC software afterwards if you are aiming for a flat response mixing room but that isn't required for most people just wanting to play their Kempers. In the playing for fun scenario a wider reasonable listening position would generally be much more beneficial than an optimized response in a single point. In this case we are talking about using home studio monitors so DRC would be a viable option but for anyone monitoring on an FRFR cab or traditional guitar cab in the room DRC isn't really an option. Some basic treatment would always be my first port of call for flexibility if the domestic environment allows. In which case I would target the corners, back wall, front wall and first reflection points in that order. Also, perhaps a little controversially, I would ignore conventional wisdom about speaker placement and place them as close to the front wall as possible. This will obviously increase the SBIR issue but will also have the effect of raising the frequencies of the problem areas into the lower mids which can be effectively treated be absorption. In an ideal world you would place the speakers in the wall (infinite baffle) or far enough away from the wall that SBIR is not an issue. Unfortunately, this would need to be around 2m for anything with genuine low frequency response which is unachievable for most rooms.

I have spent a fair bit of time and effort treating my room enough to remove problems such as a 60db dip at 137hz but will be working with a reputable studio designer on my new room later this year/early next year. At the moment I have a pretty good room to work in but it definitely isn't flat. I've just downloaded a demo copy of SonarWorks 4 to play with and see what difference it makes.

1 instrument cable + 2 x XLR is enough to get started. If you plan to reamp or record both DI and wet signal you'll need more cables to route signal back from your Focusrite to KPA.

Recording DI would require additional instrument cable.

That being said: Focusrite 414 doesn't have a lot of inputs / output so I'd encourage you to look at the Kemper manual and make sure that all scenarios you're going to use are covered in convenient way (without dancing with cables all the time). Even if you're not reamping now - you might in the future. Capturing DI is pretty much standard recording procedure.

The Focusrite 2i2 and the 4i4, don't have separate headphone power, they run off USB power.

Get the 6i6 instead, it comes with S/PDIF RCA for the Kemper, and a separate power supply, for better headphone volume.