"A brilliant modular solution for acoustic treatment"

I thought I would be reviewing an effective acoustic isolation treatment, but I have discovered that they offer far more than just that.

Why Use acoustic treatment?

Any music fanatic will be drawn towards a high-end audio gear. The latest headphones, more accurate speakers, a better DAC, pure silver cables… The quest for a perfect listening experience is a never ending journey (with serious financial investment) to uncover every ounce of magic from our beloved records. So what do I put my Money on to make this happen ?

The Key concept is overall balance. You want an appropriate balance of quality throughout your system for an optimal performance, for each budget. Putting all your money on speakers and leaving peanuts for the rest of the system will leave you worse off than spreading the budget over the various elements of your system. A good 1/3rd of this budget needs to be for acoustic treatment if you are serious about your audio.

Did you ever try out speakers at your local audio shop and once you brought them home you felt like it sounded completely different, a lot worse?

That is because the shops have showrooms that are designed by expert acousticians, with premium materials, optimal placement and quality components driving the speakers. When you get home to an untreated room, you will necessarily feel disappointed.

Besides getting better equipment, a major aspect in the way your speakers sound lies in WHERE they are placed. You are listening to your speakers and your room, never just your speakers. The worse your room sounds, the more treatment it requires. As the sound waves travel across the room, they bounce off the surfaces they encounter, causing phase cancellation in some areas, or unwanted boosts in certain frequencies. Speakers shouldn't be fighting against themselves or the room. Treat your room for better acoustics.

A combination of absorption and diffusion will help break the room modes/resonant peaks, thus helping the sound travel more accurately from the speakers to the listening position. This can be done with furniture (couch, rugs, bookshelves), acoustic foam, acoustic curtains, bass traps and room redesign (ultimately eliminating many problems at the source).

How does one know what to put where for a great result?

For one, Hofa-Akustik, offers an acoustic measurement and analysis service that will serve as the blueprint for all installations. They will then give you a non-binding planning based on the professional and accurate measurements that will give you an idea of how your room will be after treatment. Once you have agreed upon a setup, they will give you a quote for the installation. You will essentially rediscover your audio system completely with the new setup.

Why Acoustic Curtains?

The big players in acoustic treatments are thick absorbers for the usually problematic bass frequencies, medium thickness acoustic foam for midrange/treble frequency absorption and diffusers to break sound travel patterns randomly across the space. But there is one more player, A pawn ready to turn into a queen on the chess board: acoustic curtains.

But what's so special about them ?

Hofa-Akustik has not only designer extremely high quality acoustic curtains to block out sound from the exterior (a window, a door…) they have made one of my favorite acoustic manipulation tools for the studio. Originally to better isolate my window's sound leakage into the studio, which it does marvellously well with it’s 7 layers, I realized it would help control the bass frequency build up in the room. My 16m2 room would usually have lingering sub frequencies due to it's shape and size. with the curtain pulled out over the window (keeping some folds of course), the bass Impact is much more accurate and "dry".

This can be explained by the dead weight these curtains have and how much surface they cover. The bass frequencies are hard to absorbe du to their wavelength. By have a large membrane of dead weight take some of this vibration instead of reflecting it, there is a noticeable decrease in the resonance in the room.

Although the graph below shoes the absorption coefficient on a frequency spectrum for the 4 layer curtains in terms of isolation, it does not measure the reduced bass frequency resonance of a room (as I use them).

What are the benefits of these curtains over modular acoustic foam?

They are curtains. Just like normal house curtains, you can fold them, tie them, hang them… They are not as absorbante as foam, due to their lack of thickness, but they isolate well. the can make good separation between instruments in a live room, while taking up less space. They can also create temporary vocal booths on the fly.

Having these in the studio has been a real asset, especially for a relatively small room.

The Good :

1. Good isolation (7 layer version)

2. Compact when folded

3. Can be used as room bass management tool

4. Easy to install (although heavy)

5. They look great

6. There is nothing else that does what they do

7. Cut to order/custom made

8. customer service

   
   

The less Good :

1. They shed their natural cotton fibres quite a bit, which leaves a lot of dust around (bad for people with asthma, would look better if the material was more like a stage curtain)

2. They could have an extra layer that is more absorbant for studio use.

3. They are expensive for acoustic treatment/isolation

I give these curtains a solid 4/5

Disclaimer:

I have promised this review of the curtains to Hofa-akustic in exchange for a small discount. This review reflects my honest opinion based on carefully testing and using the curtains. They have not asked me to say anything specific or biased in any way.

I would like to thank Paul Batz and the rest of the Hofa-Akustik team for their quality service and generosity.