GR Research LGK 2.0 Speaker Review (A Joke)

[DSJR]

I wonder how far a big company like JBl/Harman could take a speaker in the box concept? I think maybe a small 2 way in a box. It would be fun to see how they measured and what you could tweak on them to increase performance. As usual, as scary as it is, they would probably come out good enough to fool many people who think they would sound terrible. If I was younger and working, I might have tried a 2 way cardboard box build. One of our esteemed engineers, maybe one with a son should try building one and getting it measured. I know Amir would measure it as it is so interesting! I'm thinking the box could be from high strength heavy duty cardboard (very strong stuff), not just regular weak cardboard. There I go, starting to think about the possibilities!

Late reply with apologies. In the UK, it was kind-of already done, but with little more than hardboard rather than card.

The Mission 70 used very thin panels which fit together front and back rather like a cardboard box with removable lid, the front part covered in the speaker cloth and slipping partway over the rear, making an attractive styling feature (old memories but I'm sure you can find it by searching). Innovative in the early eighties to keep a sub £100pr British made price point (far eastern manufacturing wasn't part of the UK audio scene so much then). Martin Colloms tested both versions and they did well, although at the time I wasn't a particular fan of the overall tone of the things (they still look good though looking at the pic below)

In th elate 90's, KEF developed a low cost Coda series, the award winning Coda 7, the larger fruitier toned 8 and (rather nice still) floor standing Coda 9. Again, very thin panels, plastic moulded front baffle glued on with screwed on plastic back panel and where the box resonances acted as a radiating area in the lower midrange, the whole artfully blending so well in the '7' model. The 9 may not have been so 'even, but I loved the sound overall, the whole being greater than perhaps the sum of the parts (where the art comes in in more compromised pre-Klippel speaker design (KEF did have an extremely advanced computerised testing facility though for the times, as did B&O I seem to recall, but the aims were different).

Coda 7 crossover -

 

[bennybbbx]

Just for curiosity my Sonab OA-12 measurements. Speakers are not placed symmetrically, but are next to wall. Sound is rather good but a bit dull. I bought these from the original owner 20 years ago. Source is a 25 years old car radio - solar power system...

when have such a frequency response the amp treble knob is optimal to correct it. you can try out set treble to 2 o clock and hear and measure

 

[ctrl]

it is possible to import the spl horizontal.txt spinorama data from this thread into REW . choose "import-> impulse response" and there can see the group delay . I check because speaker is because of wide band speaker simular to avatone mix cube. the best group delay is the avantone speaker. https://www.audiosciencereview.com/...ube-monitor-review.42817/page-12#post-1517193

This works only for minimum-phase systems. For a CB single driver wideband loudspeaker it works, for all other concepts no (not even for BR single driver wideband speaker), because you can only calculate the minimum phase from the frequency response and you have no possibility to get the excess phase - only both together result in the "real" phase of the loudspeaker, whose negative derivative then provides you with the real group delay.

A loudspeaker whose f3 is at 300Hz, like the Avantone, which is basically a midrange driver, almost always has a relatively low group delay. But the necessary subwoofer (to listen to music normally with it ) leads overall without FIR to no better result than well-designed speakers - very likely even to worse GD than from 2-way speaker with the usual 2-3kHz crossover frequency in the frequency range below 400Hz.

 

[ctrl]

there is solution with spinorama. Need before choose in REW get minimum phase to see the excess group delay,
I did not thought excess group delay change so much. in excess group delay the yamaha HS 5 is the best. i try to remove all grpahics i post so far and add new with excess group delay. then best is when @amirm post excess group delay too ?.

You got it wrong again.

The Spinorama files of measured speakers Amir offers contain only frequency response data (no phase response data). The phase frequency response that REW shows you (after importing Amir's data) is already the minimum phase, because only the (amplitude) frequency response data was available (and REW probably calculates the minimum phase from the frequency response via Hilbert transformation).

From the Spinorama data published by Amir it is impossible to generate the excess phase frequency response or the complete phase frequency response of the measured speaker. So the group delay generated from the Spinorama data is not correct either - the only exception where this difference hardly matters are CB single driver full range loudspeakers.

 

[BDWoody]

Let's not derail this thread further please.

 

[Geert]

Let's not derail this thread further please.

Is it OK to derail the Avantone review thread with the same type of posts? https://www.audiosciencereview.com/...one-pro-mixcube-monitor-review.42817/page-13?

 

[bennybbbx]

Let's not derail this thread further please.

ok, i delete all about this group delay thing now. I ask REW autor and link him this spinorama files. he write https://www.avnirvana.com/threads/i...-in-group-delay-and-excess-group-delay.11849/

those files are not impulse responses, they are columns of SPL values at different angles. REW cannot import them correctly as it assumes the third figure in each line is a phase value, it is actually a repeat of the frequency value for the next set of data. There is no phase data in the file so nothing to use to generate group delay. Producing a minimum phase response from the SPL values doesn't tell you anything about the measured phase.