Concrete Speakers from Timber West Design Tested by GRResearch‬

[WillBrink]

Cabinets made of concrete using GR drivers. I hear mixed opinions on GR drivers. Vid covers design and manufacturing of the cabinets and testing by Denny. Maybe Erin or Amir will test them some day. There's nothing new about using concrete for cabinets, using 3D printer for different shapes intrigues me. I could really live without the cheesy background music:

 

[Beave]

Aren't you supposed to give a summary of the video and reasons why we should bother to watch it?

Because I'm not watching any more Danny-related videos. It's a waste of time, and each view could be seen as a positive for Danny's BS.

 

[BillH]

Cabinets made of concrete using GR drivers:

Seconding @Beave
Posting linked content is only allowed if you summarize or make comments on the content of the shared content

 

[RickS]

@WillBrink per ASR policy, offsite content requires at least some statement about why or why not may be worthy of member consideration.

EDIT: Thanks for the update

 

[terryforsythe]

The video presents some test data. The cabinets are very inert; the burst decay is extremely good, especially with the spherical cabinet shown in the video's cover picture. I'd like to see Amir or Erin do a full suite of test data and review but, based on the test data that was presented, they probably will sound very good. I don't recall seeing pricing information in the video, but I didn't watch the entire video - I jumped to where the data was presented. It will be interesting to see where the price comes in.

 

[Beave]

The video presents some test data. The cabinets are very inert; the burst decay is extremely good, especially with the spherical cabinet shown in the video's cover picture. I'd like to see Amir or Erin do a full suite of test data and review but, based on the test data that was presented, they probably will sound very good. I don't recall seeing pricing information in the video, but I didn't watch the entire video - I jumped to where the data was presented. It will be interesting to see where the price comes in.

Perhaps, but since Danny's measurements are of such low resolution compared to Klippel NFS measurements, it's really hard to tell much or to compare those measurements with anything done here or by Erin's Audio Corner. The cabinets probably are very inert, but how can we know that for certain with such poor resolution measurements? And the decay looks good too, but in Danny's measurements, it's more just a reflection of the on-axis response being smooth. And Danny's measurements are always overly smoothed compared to Klippel resolution.

 

[Puddingbuks]

This is what I posted by this video:

@4:36 these speakers measure really bad. Very uneven frequency response and very different off axis sound. The measurement is even taken at 1/3 of an octave smoothing, so it looks smoother, but other measurements are at 1/12 or 1/20 of an octave. Compare this measurement to a kef LS60 and you will see (and hear) how a natural, flat speaker will be. More on the measurements: The CTA-2034-A standard (which defines how "Spinorama" data should be captured and presented) recommends a frequency resolution of at least 20 points per octave. This ensures that the data is high-resolution enough to show meaningful resonances without being so "busy" with minor measurement artifacts that it becomes unreadable.

Bottom line for me:
- a good cabinet is not the only problem to solve
- there are other ways to reduce cabinet resonances, like dual opposed woofers.

My kef LS60 in stereophile:

 

[RobL]

1/3 smoothing but 25dB axis on the plots….tweeter beams but overall doesn’t look too bad to me:

Horizontal


Vertical:


Decay:


Impedance:

 

[RickS]

Perhaps, but since Danny's measurements are of such low resolution compared to Klippel NFS measurements, it's really hard to tell much or to compare those measurements with anything done here or by Erin's Audio Corner. The cabinets probably are very inert, but how can we know that for certain with such poor resolution measurements? And the decay looks good too, but in Danny's measurements, it's more just a reflection of the on-axis response being smooth. And Danny's measurements are always overly smoothed compared to Klippel resolution.

…and still no measurements (most notably CSD) below 200 Hz. The one design has decent directivity but you do not need concrete to get that. These are novelty speakers at this point and just because some mediocre measurements were done, does not make them great. Conditions matter and when you have no data on the lower 3 octaves, you are missing a significant portion of the spectrum.

The website has lovely outdoor structures but nothing more than design files for the speaker cabinets. At this point, is more like an experiment than a vetted product design. Using GR drivers demonstrates a lack of experience and would be a poor choice for an outdoor speaker.

 

[terryforsythe]

…and still no measurements (most notably CSD) below 200 Hz.

That is a limitation of Danny's measurement setup, and can be problematic. I'd be curious whether his crossover designs for these speakers implement baffle step compensation and, if so, how accurate he has implemented it given the lack of measurement data below 200Hz.

 

[terryforsythe]

@4:36 these speakers measure really bad. Very uneven frequency response and very different off axis sound.

That is with the semi-rectangular cabinet. When comparing to Amir's and Erin's measurements, keep in mind that they typically use a 50dB scale, whereas the measurements presented in the video are with a 25dB scale.

@6:09 the FR data for the spherical design is presented. It looks good; +/- 1.5dB on axis 200Hz - 18kHz measured 1/3 octave and well controlled off axis. I'm sure when measured at 1/12 octave there will be more fluctuations, but whether they will be audible is debatable. The bigger issue is the lack of data below 200Hz.

 

[terryforsythe]

Compare this measurement to a kef LS60 and you will see (and hear) how a natural, flat speaker will be.

The KEF LS60s are wonderful - I have a pair.

But, comparing relatively small passive 2-way bookshelf speakers to the LS60s is a bit of an apples to oranges comparison - the LS60s are all active, have 4 servo controlled woofers in each speaker, have a concentric driver, are towers (albeit small ones), etc. They are not even in the same league. Now, if the prices of the speakers in the video come anywhere near the price of the LS60s, that would be a big problem for them.

 

[DanielT]

Regarding

Cabinets made of concrete.... There's nothing new about using concrete for cabinets..., using 3D printer for different shapes intrigues

There's nothing new about using concrete for cabinets..
That's right. In line with the thread, if it's about concrete as a building material for speakers, I can mention that about twenty years ago I had a pair of concrete speakers.
When I bought a pair of Ranua Njords at the time, those speakers were already twenty years old.

Rauna Njord, Transmission line construction:


They sounded, as far as I remember, ok. It's been a long time since I sold them.They were heavy of course.

Here @MAB and his Rauna Freja concrete speakers. Measurements on them and history about the manufacturer Rauna in the thread:

Rauna Freja Vintage 2-Way Loudspeaker Measurements

Today I present measurements on a pair of Rauna Freja, aka affectionately as 'Swedish Tombstones';). They are a small 2-way in a concrete cabinet. I believe that Bo Hansson was involved with the design. I would appreciate any information members have regarding this nice little speaker. These...

www.audiosciencereview.com

Here is Rauna's latest model, Oden:

"Oden's eye" consists of a 6.5 inch coaxial element (midrange tweeter) with cone material in stiff and light magnesium/aluminum and magnet system in neodymium. The 8 inch bass is a completely newly developed woofer.

Rauna Oden

Rauna Oden briljerar med oöverträffad prestanda. Det är resultatet av fem års utveckling och 50 års erfarenhet av högtalarbygge, en sann trevägare som sätter ny nivå på glädjen i musiklyssning.

www.hifikit.se

 

[Buckchester]

I don’t trust anything from this Danny charlatan. He doesn’t follow established practices and procedures and he appeals to the ignorant. Next.

 

[Jim Taylor]

... I'm not watching any more Danny-related videos. It's a waste of time, and each view could be seen as a positive for Danny's BS.

Hear, hear! Clicks to condemn are still clicks, and YouTube doesn't care. We at ASR are probably his greatest enablers! Shame on us!

 

[DanielT]

....using 3D printer for different shapes intrigues me...

I missed pointing you to this thread yesterday:

3D Printed speakers - Unlock impossible designs compare to conventional

Hello, After some look around the forum, I could find few posts around 3D printing but I could not find a particular thread related to 3D Printed speakers as a method of building D.I.Y speakers. I have not tried myself yet but I will list the different projects I could find to start the...

www.audiosciencereview.com

 

[Aerial Acoustic Guy]

I don’t trust anything from this Danny charlatan. He doesn’t follow established practices and procedures and he appeals to the ignorant. Next.

I agree, but I do like his videos, specifically because you get to see the drivers and crossovers outside their enclosure.

 

[RickS]

I agree, but I do like his videos, specifically because you get to see the drivers and crossovers outside their enclosure.

His teardowns can be interesting and have watched the first half of some with just closed captioning and no audio. This way is easier to ignore the subjective propaganda spew and Danny's tendency to apply solutions that are questionable while ignoring more fundamental design issues.