What makes a speaker sound boxy? the box?

[ginetto61]

This is largely what is done in the PA industry but never seems to have caught on in hifi circles...

hi actually i was thinking to these speakers

or this one One driver one cabinet

There is actually much to be learnt by hifi DIYers from PA developments, but many purists simply turn their noses up at anything rugged and designed to be bashed about by roadies!
Further, the pricing of PA drivers is far more realistic than those destined for home use, and there are some incredible bargains to be had.

Thanks a lot Actually there is guy here in Italy who has started a crusade in favor of the use of PA speakers even for home listening
I think that the major limit for these systems is their rather demanding physical appearance
on the other hand models based on narrow columns of full-range little drivers in array above a bass box could have a certain appeal
I've never heard one

 

[tubelectron]

Iron frames are not stiff, compared to two boards glued together at 90°.
The steel frame will be ringing like hell. You really want boards bonded together at angles. This is what provides stiffnes!
Thin plywood mounted with magnets sounds like a bad idea ...
Ciao e auguri!

Well, you nearly said it all, @stv ! 😕

When I was speaking about 20mm thick steel plates, they were all edges chamfered and welded between them, on each side ; "welded all over and tight", like a pressure vat.

For the 475L enclosure, it would have represented a steel cabinet of an absolute stifness and mass combination, but the weight would have been at least circa 270kg... 😱

You note that my 375L and 475L have both their panels joints first glued, then assembly-straigntened inside by glued angle battens. Only the 475L has bracing and damping additional features.

T

 

[ginetto61]

Hi and good morning to Everyone !
i have just a curiosity I am reading this page

https://www.stereophile.com/content/bw-matrix-801-series-2-loudspeaker-measurements

That this graph is free from any glitches that would indicate the presence of enclosure resonances was confirmed using a simple plastic-tape accelerometer to assess the panels' vibrational behavior. Waterfall plots calculated from the accelerometer output when it was attached to the sides of the fibercrete "head" unit (fig.2) and the Matrix bass bin (fig.3) showed that both were almost completely free from the ridges of delayed energy that would imply the presence of panel resonant modes.

i wonder why almost never they attach accelerometers to the front baffle that It is most likely the most critical panel for any vibrations
i find this weird I would like to begin the new year understanding this
I am thinking to write to Mr Atkinson directly and ask

 

[Andersonix]

An inexpensive piezoelectric-tape (polyvinylidene fluoride) accelerometer, 4" long by 1" wide and similar to anacoustic guitar transducer [43], is taped to the cabinet walls at various places, the cabinet is excited with a 2kHz-bandwidthtest signal from the DRA Labs MLSSA system at a standard level, and an impulse response is calculated/captured.

From JA to you in 1998

 

[ginetto61]

Hi ! thank you very much My question was about the placement of the accelerometers They place them everywhere but the most important panel by far i.e. the front baffle Side top and even back panel But never on the front baffle close to the drivers
Anyway now that i think better i will check if they have tested an open baffle speaker In that case the choice is forced

i checked found one https://www.stereophile.com/content/larsen-hifi-8-loudspeaker-measurements

the performance looks quite good I wonder why they do not always test in this way
by the way what a strange speaker No comment

 

[NIXIE62]

Maybe they know something we don't know? 😀

 

[ginetto61]

from the review

It's a Scandinavian loudspeaker, and Scandinavian speakers are subject to a different and altogether more liberal set of rules.

now i can understand the speaker better
i remember Rauna brand using to make concrete cabinet speakers Never heard one but i have the feeling that they did not sound boxy at all
i read a review mentioning a great soundstage and very transparent sound Unfortunately extremely heavy
Going back at the last question i would like to repeat the vibes measurements on all panels to check each individual contribution to resonance
Both in level and frequency I think that it is a very telling test indeed
I wonder if the equipment needed to carry out the test will be very expensive

 

[Andersonix]

How did I not know about Rauna?? Making concrete loudspeakers since 1982...?
https://rauna.com/pdf/betongaomrauna.pdf

Rauna had a slogan: "The worst thing you can build out of six chipboard pieces is a loudspeaker".

And how do you not already have a pair of Rauna Oden?

 

[ginetto61]

Hi ! these are much nicer than the Tyr model I have seen some DIY projects using concrete It is quite a mess
if i had the chance i would still look at metals They are very stiff and as i understand this properties shifts resonances up in frequency
High Hz resonances should be low in energy and very easy to damp with some sheets of proper materials
Stenheim do this using aluminum panels damped with some sheets of viscoelastic material
And all this just for the bass box
By the way i am reconsidering the range to cover with the woofer after noticing that instruments like voice and drums share a good portion of the audio spectrum
A speaker i love deeply the old JBL L166 uses the 12" woofer up to 1kHz
another one the L100 even up to 1.5kHz 😱
i was thinking of using instead a midbass from lets say 200-300Hz
this will make the bass cabinet design and construction even more important