Tuning cabinet vibrations in a real world speaker

It’s not a  secret that dealing with cabinet vibrations is a big thing here at Fink Audio-Consulting. Now that everybody managed to make the speaker drivers better and better,cabinet vibrations are a lot easier to detect. The “nice” masking effect of IM and harmonic distortion is not longer there, so we are able to detect the nasty resonances  of real world cabinets.

A few methods have been developed over the last years to control,damp and shift cabinet resonances. Sure,you can go the WILSON way and make your speakers 100kg heavy,but for cheaper speakers this does not work of course.

But what is the best way? How much resonances can we accept? Is it frequency dependent? Yes,it is. Reading the research results of the BBC, you will notice learn that they found cabinet resonances in the higher midband are evil. But the typical well braced cabinet gives you resonances in the 800Hz-2kHz region. Not very nice as it adds  roughness to voices and some unpleasant forward presentation. It’s better to allow the cabinet resonances below 400Hz –this adds some warmth to the performance and can sound a lot more musical.

Here ia a comparison between two different cabinet concepts:

ls50 vs concept20

The blue line shows  cabinet vibrations (one side panel) of a well respected British speaker with a lot of bracing. The bracing is not directly connected to the walls,but has a layer of rubber in between. The cabinet is relatively heavy and feels very solid.

The red speaker shows the side panel of a similar sized speaker –made for another British brand. This speaker is only lightly braced,but uses a sort of sandwich construction with 2 layers of MDF and a lossy layer in between.

As a result we see  two complete different philosophies:The blue speaker is very well damped between 200Hz and 500Hz. Above 800Hz,the level goes up  stays high up to 2.5kHz.

The red speaker got the maximum output at 300 and 400Hz,but drops after 500Hz (the peak on both speakers at 700Hz is the stand) and stays very low up to 2 kHz.

Funny enough,you can hear the same thing listening to the speakers:The blue one is very tight,but a bit lean on lower midband and  a forward imaging with flat,but wide sound stage.

The red speaker got definitely more warmth,but with a very open,natural midband character. The image is completely different. It is not as wide as the  blue speaker,but with much deeper soundstage and realistic rendering.

Our development shows that cabinet vibrations not only disturb the midband character,but also shift image around. Just make a simple experiment yourself that I learned from fellow Stephen Harris (Audioplus UK):Listen to a bookshelf speaker on a stand and concentrate on the height of the soundstage. Now take a book or something similar and place it on top of the speaker. In most cases you will immediately notice that the soundstage  goes up. What is happening? Well,the book reduces the output of the top panel. The same thing happens with well controlled and damped cabinets:The soundstage is more realistic and not influenced by peaks and dips radiated from the cabinet panels. Not to forget the more relaxed and natural midband :-)

More to come..

 

Essen,24.11.2014 Markus Strunk and Karl-Heinz Fink

 

KLIPPEL Laser Scanner

In addition to our POLYTEC Laser Scanner,we got the Klippel Laser Scanner recently. Why? Well,the Klippel device uses a Triangulation Laser and can output dimensions. It also couples the measurements to the surrounding air and allows to predict SPL including directivity –with a simple click only.

Here is what you get as . . . →Read More:KLIPPEL Laser Scanner

OK,late again with updates:-(

Last time I promised to write more –unfortunately it did not work out. Too much work and not enough time.

A lot happened –new people,new equipment and new customers.

I’ll report about the new people soon and add them to the list and I’ll also report about the new Klippel Scanning Laser . . . →Read More:OK,late again with updates :-(

Find your Album Art with BLISS

My music collection is on the Computer now. Grown over years,it’s a collection of all sorts of music,ripped with EAC and that means no Album Covers. And as I’m very lazy,I never found the time (and the motivation) to sit down for hours and search for Album Covers on the net.

Good . . . →Read More:Find your Album Art with BLISS

Effect of Thermal Compression in real world subwoofers

Whenever we at FAC design a subwoofer,we test after finishing the equalizing what the loudspeaker does at higher levels. The best method is to do a compression measurement. During this measurement,the input level of the subwoofer is increased and we check if the output level changes follows

A subwoofer after filtering

If . . . →Read More:Effect of Thermal Compression in real world subwoofers

Stitching together nearfield and farfield loudspeaker measurements –Part 1

Nearly everybody in our industry knows the AES article about nearfield measurements of Don B. Keele introduced in 1974. In his article,he described a way to make a nearfield measurement of a speaker and he compared it with the farfield response of the same speaker. He came to the following conclusion:Based on that . . . →Read More:Stitching together nearfield and farfield loudspeaker measurements –Part 1

HighResDownload

Carsten Hicking of DigitalHighend published a page with links of websites for High-Resolution Audio downloads. Please support him if you find more and let him know,so the page can be updated. HighResDownload

On the left the company dog of DigitalHighend

Loudspeaker measurements on a MAC -Room EQ Wizard

OK,the headline is not really correct. Room EQ Wizard is not only for MAc,but also for Windows and Linux. However,as a Mac user,it’s difficult to find a measurement tool and so I’ll introduce whatever I find in the near future.

Room EQ Wizard is a Java application . . . →Read More:Loudspeaker measurements on a MAC -Room EQ Wizard

AMARRA goes version 2 soon and adds FLAC

In a few weeks you can expect to see version 2 of our favourite Playback software in our listening room. The new AMARRA version will play FLAC files and supports playback without Itunes via Playlists

Already in the old version,the Playlist Mode was already the better sounding one,but now in version 2,Sonic . . . →Read More:AMARRA goes version 2 soon and adds FLAC

I promise to work harder –latest news

Hi,

OK,it looks like I’m a bit lazy and I did not write a lot here during the last few month . However,I’ll try to do more now and I’ll also get help from Christian Gather,our lastest team member,who was Editor in Chief of Germanys most successful speaker magazine KLANG . . . →Read More:I promise to work harder –latest news