Project for speaker boxes for BG-20 Visaton

[Tony44]

Hi guys!
I need a project for speaker boxes for BG-20 Visaton.
thanks!

 

[freddi]

it should work in a Karlson in 0.65 K15 scale and K12 - - -


TheJessMan has his in GregB's Karlsonator 8 which goes lower than a K12 size

Karlsonator 8 build
https://www.facebook.com/media/set/?set=a.645456515500837.1073741837.601735219872967&type=3

it will work in MLTLs - I had one in a fake Druid pipe and it was pretty good -

 

[freddi]

Scottmoose described one in this thread http://www.diyaudio.com/forums/full-range/227866-tl-box-bg20-visaton-2.html#post3331238

also, Visaton recommends a 50 liter box tuned to 42Hz for BG20 - there's a "Cheap Trick" build where the whizzer cone is removed leaving a smooth wideband unit to be used with a helper tweeter

http://www.lautsprechershop.de/inde...lautsprechershop.de/hifi/ct230_en.htm?xxx?xxx



Technical data:
- size (HxWxD): 58.6 x 35.6 x 33.4 cm
- impedance: 6 Ohm
- sensitivity (2.83V/1m): 89 dB
- frequency range (-8dB): 33-21 000 Hz
- speaker type: 2 way bass reflex

 

[Tony44]

Which of these two variants to choose Karlsonator 8, or TQWT box with BG-20 (Simphony BG-20), that is, which gives a better sound?
thanks!

 

[xrk971]

Which of these two variants to choose Karlsonator 8, or TQWT box with BG-20 (Simphony BG-20), that is, which gives a better sound?
thanks!

Both designs use a ML-TQWT to achieve bass extension but the Karlsonator will sound better because it uses the K aperture to blend the LF and HF to emanate from a common point and it provides a wide uniform dispersion of all frequencies from bass up to 10khz within 5dB over 90 deg coverage. The sound from a Karlsonator will be very rich, full and very big. I have never heard an open-faced direct radiator to sound as good as the equivalent with a K aperture. There will be some mild coloration in terms of minor frequency response dips in lower mids but they are not objectionable or noticeable. My vote is the Karlsonator. Look at mini Karlsonator thread and see how many satisfied builds there are. It is almost a perfect record of happy builders. There are a few cases where people could not get it to work but that was either a bad build with a leak or floppy cardboard materials. A pinhole leak in TL will collapse the deep bass capability. Same way a finger pad leak on a flute prevent lowest C note being played.

 

[Greg B]

Which of these two variants to choose Karlsonator 8, or TQWT box with BG-20 (Simphony BG-20), that is, which gives a better sound?
thanks!

Like x says, they are both essentially ML-TQWT. What's 'best' depends on many factors, including your own taste and the room size and acoustics. Certain aspects about speakers can be measured objectively, but how you value them is subjective.

An obvious difference here is enclosure size. The Simphony is 3x bigger by volume than the Karlsonator 8, which will greatly influence bass response. For the VisatonBG-20, my gut feeling based on specs is that it would be better if scaled up in size. I'd guess about 25%, which will approximately double the volume. A sim or two should be looked at first though.

IMO the Simphony has been maximized for deepest possible bass extension. I typically prefer a smaller volume TQWT with a slightly higher tuning. This favors a strong and solid midbass over deepest possible bass. That is usually the tradeoff. It's a taste thing though. Also, it depends on the room.

That cheap trick 230 looks like a cool and simple design, but it is a two-way, albeit with an unfashionably high crossover point. I'd consider it though. Probably very nice.

The other big thing to mention is that the BG-20 has seriously climbing treble response, and this is before the baffle step. A Karlsonator will likely be just fine with the driver direct wired, but the Simphony and about anything else will require an electrical notch filter.

 

[Greg B]

For the VisatonBG-20, my gut feeling based on specs is that it would be better if scaled up in size. I'd guess about 25%, which will approximately double the volume. A sim or two should be looked at first though.

Sorry that's not clear. Written before coffee.

I mean the Karlsonator 8 would be better if bigger.

The Simphony is definitely on the big side already.

 

[GM]

I typically prefer a smaller volume TQWT with a slightly higher tuning. This favors a strong and solid midbass over deepest possible bass. That is usually the tradeoff. It's a taste thing though. Also, it depends on the room.

With bass, very much so; my room has very little gain even in corners, so need all the acoustic gain I can 'afford' whereas someone in a concrete room only needs a low tuning with the bass rolling off at ~80 Hz or even higher in some apps.

GM

 

[freddi]

I don't know thejessman's measurement conditions but fwiw here's his BG20 in his Karlsonator8 (red) vs the same BG20 in my Karlsonator12 - - (his mic obviously was off the central HF lobe)

I liked BG20 in the little 35 liter fake Druid pipe - I may mount one again with a "phenolic" ring helper tweeter - the
tweeters I have need impedance nulling to work right

here's my BG20 in a 7-slit vent Karlson12 copy vs the newer Beta10cx woofer section - IIRC, the mic was pretty much pointed
at BG20's dustcap/whizzer

An externally hosted image should be here but it was not working when we last tested it.

 

[Greg B]

Interesting. Thanks Freddy. So it works pretty well in the 'standard' K'ator 8 as well as the much bigger full sized Karlsonator. Presumably an in between one as I suggested would be fine too, but not strictly necessary. Considering I originally used the FE206 to kludge the modeling, I'm a little surprised it works this well with the BG20 specs.

Either way, this Visaton driver in a Karlsonator will have a moderate smiley curve in the response if not EQ'd. This makes for a mellow sound and helps to make poor recordings sound better, but it's not to everyone's taste. If the flattest possible freq response is desired, starting with a conventional TQWT or BR and using notch filters and EQ to correct the response may be better.

 

[Tony44]

Gentlemen, what is the Qtc to boxes at Karlsonator8 in Simphoni BG-20?
How much lower the frequency at -3 dB in one and in the other boxes?
thanks!

 

[Greg B]

Qtc is typically used to described sealed boxes, not vented. In both cases it would depend on how much stuffing is used. You could measure it after assembly, or take it from one of the posted graphs - if you care to do the math.

The F3 is going to depend on the driver used. Looks like about 42hz with the BG-20 in a Karlsonator 8. I've no idea what it is for the Simphony. Should be lower as it is 3x the volume.

 

[Tony44]

Qtc is typically used to described sealed boxes, not vented. In both cases it would depend on how much stuffing is used. You could measure it after assembly, or take it from one of the posted graphs - if you care to do the math.

The F3 is going to depend on the driver used. Looks like about 42hz with the BG-20 in a Karlsonator 8. I've no idea what it is for the Simphony. Should be lower as it is 3x the volume.

This is Simphoni BG-20!!

 

[talaerts]

There are interesting projects in the German magazines with it. In some cases they even cut the tweeter cone out and add an extra magnet (project Aurum, and I think Notch as well)

Check here and click Bausatze einblenden to expand the projects:

http://www.lautsprechershop.de/chassis2/visaton_fullrange-bg-20-8-ohm.htm#V-3020