Gravity Well Of A DarkStar

0 Members and 3 Guests are viewing this topic. Read 443707 times.

Vinnie R.

  • Industry Contributor
  • Posts: 4910
    • http://www.vinnierossi.com
Re: Gravity Well Of A DarkStar
« Reply #1080 on: 29 Aug 2006, 12:27 am »
Hi John (Acudoc),

Welcome to the RWA forum!

I had the opportunity to give the Solovox a listen a few weeks ago at In Living Stereo in NYC.  They are very unique in design and sound.  They are called an open baffle speaker, but their design not like other OBs that I've seen.  If you put your ear to the back center area, the sound has more bass than top end.  If you listen to the two sides (the small openings that are formed with the curved plywood), you hear more top end.   They use an OEM PHY 8" driver.  I was able to borrow what appears to be a similar driver, the PHY H 21 LB 15.  In my OBs I found the B200 sounded MUCH better.  But a similar looking PHY driver in the Solovox was quite impressive  :)  That is not a cheap speaker though...around $10k I believe  :o

Regarding the new Hemps, Louis is working on a new OEM high-Q driver with new basket, new magnet, new other stuff (and he is no longer associated with Hemp Acoustics...he is working directly with the Tone Tubbey guys and things have been moving forward much more quickly these days).  I can't wait to hear it!

As far as an OB circle, I think it would be a nice addition to audiocircle.  Are people still interested? 





-Richard-

  • Full Member
  • Posts: 853
Re: Gravity Well Of A DarkStar
« Reply #1081 on: 29 Aug 2006, 02:51 am »
Ahhhhh... the Dark Star thread has opened up again... phew!!!! all the oxygen had been
used up for quite a while... but now I can breath fresh air again ~

Keep us informed JeffB of your progress and your observations... remember we are all
learning here... so this is a very opened-ended exploration where what we hear is
what we learn
... so give yourself over to hearing your music with a fresh take on what
your OB's are doing to bring new life and space and intelligence to your music!!!

What I have learned has shattered any previous ideas I held about what was possible
in audio... a priceless opportunity to rethink everything awaits you ~

Warm Regards ~ Richard ~
« Last Edit: 29 Aug 2006, 04:29 am by -Richard- »

Russell Dawkins

Re: Gravity Well Of A DarkStar
« Reply #1082 on: 29 Aug 2006, 04:09 am »
I was able to borrow what appears to be a similar driver, the PHY H 21 LB 15.  In my OBs I found the B200 sounded MUCH better.  But a similar looking PHY driver in the Solovox was quite impressive  :) 

Vinnie, I would be interested in knowing your impressions of the difference between the PHY H 21 LB 15 and the Visaton B200. Interesting that two so highly regarded drivers can sound so different, isn't it?

It seems that Keith Aschenbrenner holds the PHY 8 in great respect:
http://www.6moons.com/audioreviews/auditorium23/23_3.html  (middle of top paragraph)
or
http://www.6moons.com/audioreviews/auditorium23/23.html
for the whole story.

Polarbear

Re: Gravity Well Of A DarkStar
« Reply #1083 on: 29 Aug 2006, 09:39 am »
Nice to have you around Björn. You should be able to comment about the Bastani Prometheus and those felt applications and also about
monopole vs dipole bass.

/Erling

Hi Erling and all others.

Regarding the feltpads, which are helping the HF dispersion as said, I have not tried without them. Another trick Bastani have done, is lacquer the wideband in a special way to make a controlled breakup and prevent beaming.

After reading this tread about wing/no wing, I wanted to try without wings. I unmounted the sides, and put some L's behind the baffle to keep it standing on the subs. The difference is easy heard. A better sondstage and less resonant performance. I realize I have redo my baffles/sidepanels with no obstacles on the side. The strange is, that there is not munch sidewings at all. Even so the effect is quite dramatic. (http://home.no/tricoloreis/18.JPG) (http://home.no/tricoloreis/21.JPG)

I have also upgraded the tweeter to MK2. It's a hornloaded dipole tweeter. A nice upgrade which integrated better with the dipole widebander.

Closed vs dipole woofer. I think you can make good solutions both ways. But in my opinion, it's easier to make a good dipole woofer, than closed box. It's much more demanding in making and integration. The box must be built like a tanks, and has to be carefully tuned and placed in the room to not attract attention. But there is a lot of considerations to deal with in choosing woofer system. Roomsize, placement, taste of sound, X-over freq., spl +++
In a small room, stereo against the backwall, you'd be better off with a closed woofer I'd think ;)

Cheers
Bjørn :thumb:
« Last Edit: 29 Aug 2006, 01:58 pm by Polarbear »

scorpion

Re: Gravity Well Of A DarkStar
« Reply #1084 on: 29 Aug 2006, 01:38 pm »
Hi Björn,

Thanks for your comments ! It is always with envy that I look at pictures of your beautiful speakers. I am no good carpenter I am afraid.
But now you seem ready to do away with some of that nice wood because wings are detrimental. Well, I suppose I have to
back down from my somewhat nasty comment made earlier. Mind you, I have always tried to avoid wings to form parallell surfaces
with my OBs.

But if I read you right your impression is that both sound an image were not subtly but in fact substantially improved when you removed
your small side wings. That is interesting ! Another exemple of what is nowadays coined 'lifelong learning'.  :D

I got my 16 8-inchers today. I'll come back with some discussion about what to do with them.

/Erling

Polarbear

Re: Gravity Well Of A DarkStar
« Reply #1085 on: 29 Aug 2006, 02:01 pm »

But if I read you right your impression is that both sound an image were not subtly but in fact substantially improved when you removed
your small side wings. That is interesting ! Another example of what is nowadays coined 'lifelong learning'.  :D

I got my 16 8-inchers today. I'll come back with some discussion about what to do with them.

/Erling

Thanks for your kind words Erling.
I used the wrong word for it yes :-) The change in sound is definitively there. I would say the change was for the better yes.

Cheers
Bjørn

Wind Chaser

Re: Gravity Well Of A DarkStar
« Reply #1086 on: 29 Aug 2006, 04:06 pm »

After reading this tread about wing/no wing, I wanted to try without wings. I unmounted the sides, and put some L's behind the baffle to keep it standing on the subs. The difference is easy heard. A better sondstage and less resonant performance. I realize I have redo my baffles/sidepanels with no obstacles on the side. The strange is, that there is not munch sidewings at all. Even so the effect is quite dramatic. (http://home.no/tricoloreis/18.JPG) (http://home.no/tricoloreis/21.JPG)


Bjørn,

Welcome to the club of higher discernment.  We look forward to reading more of your insights and contributions in all things OB

Isn't interesting how the effect of even most diminutive wings takes its toll on the soundstage?  You might want to share your revelation with Bastani.  In doing so you'll be able to take credit for improving the design.  :thumb:


John

Wind Chaser

Re: Gravity Well Of A DarkStar
« Reply #1087 on: 29 Aug 2006, 04:24 pm »
Scorpion,

I'm sure you will find the opening of the soundstage without wings to be very obvious.  The nice thing about OB is you don’t need anything more than the most nominal carpentry skills.

John


scorpion

Re: Gravity Well Of A DarkStar
« Reply #1088 on: 29 Aug 2006, 10:57 pm »
With regard to the Bastanis and Polarbear's find, it is rather Siegfried Linkwitz that should reconstruct the Orion !  :D

/Erling

Vinnie R.

  • Industry Contributor
  • Posts: 4910
    • http://www.vinnierossi.com
Re: Gravity Well Of A DarkStar
« Reply #1089 on: 30 Aug 2006, 12:14 am »

Vinnie, I would be interested in knowing your impressions of the difference between the PHY H 21 LB 15 and the Visaton B200. Interesting that two so highly regarded drivers can sound so different, isn't it?


Hi Russell,

I used the H 21 LB 15 in my OB.  Compared to the B200, the top end lacked extension....certainly less detailed and less spacious.  The mids were ok, but the B200s offered better clarity and just a better overall sense of what was going on in the recording.  The bass of the B200 was tighter, "punchier", and was able to be played louder without showing signs of overload.  The PHY in my OB just didn't cut it for me and after about an hour of sampling different tracks, I couldn't take it anymore and put the B200s back in and EVERYTHING sounded so much better  :singing:

Note -- This is NOT my impressions of the Auditorium 23 Solovox, which uses a very similar looking PHY (it is actually an OEM driver with a different voice coil and a few other mods I believe I read).  The Solovox left me very impressed after listening, and left me wanting to hear more of it and to learn more about the design.  It is a fascinating design IMO!  :idea:

Also note that the OB recommend by PHY for the H 21 LB 15 is a similar design to what I'm using, but larger, as shown here:
http://www.phy-hp.com/English/Communication_E/Com_E_Baffle_Plan.html


All,

I am getting opposite results with the wings.  When I open them up I seem to be getting a larger soundstage and these OBs image extremely well. 

Just to recap on my OB design:

-- The center baffle is 10" wide
-- One wing is 12" wide and the other is 13.5" wide
-- The height is 48". 
-- The material is 0.75", 13-layer baltic birch ply that is vaneered on both sides (vaneer uses a phenolic backing). 
-- The wings are attached via "piano style" hinges.  Sandwiched between the hinge and the wood is now a layer of foam gasketing tape, which is crushed in between when the screws are torqued down.  I am now using beefier screws that really make the hinges tight.  I need to take new pics.  They are very solid!
-- I have the wings open about equally... about half way between fully opened and fully closed.  The larger wings are on the outside.
-- Baffles are approx 5 feet out from the wall behind them.

As has been mentioned here in the past, adjusting the wings adjusts how the backwave interacts with your room.  I've used wingless baffles before (about 24" wide), but the wings are working very well in my situation.  Luckily, it is very cheap to experiment on some plywood.  If I were new to this and starting out, I'd try it a few different ways and see what works best for your situation. 

I also want to add that I've been really enjoying reading all of your different experiments and experiences here!   :thumb:



BrassEar

  • Jr. Member
  • Posts: 248
Re: Gravity Well Of A DarkStar
« Reply #1090 on: 30 Aug 2006, 12:19 am »
OK, I have a question for Richard. I'm assuming the answer is not contained in the 100+ pages of this thread.

Not to sound flippant but is this Visaton B200 thing for real? I am a big Maggie fan (addicted is more like it). Since you used to own and comment on the 1.6, how on earth can the B200 open baffle compare to the Maggie?

Maggies + Tripaths are a magic combo IMO. Would seriously love to read your thoughts on this.

Dmason

  • Full Member
  • Posts: 1283
Re: Gravity Well Of A DarkStar
« Reply #1091 on: 30 Aug 2006, 12:20 am »
Vinnie

Do you notice a difference, with the gasket foam as a decoupler? Mo' pix please. Sooo glad you like. My main convert.

A note about wings: One wing works really well too, especially if you have use of side walls. You pick up the freebie bonus of boundary gain of the wall, in the lower register, if you tape the edge of the outside wing to the wall. Now you have boundary gain from the floor AND the wall.  \__     __/

Vinnie R.

  • Industry Contributor
  • Posts: 4910
    • http://www.vinnierossi.com
Re: Gravity Well Of A DarkStar
« Reply #1092 on: 30 Aug 2006, 12:59 am »
Hey Dmason,

YES!  The gasket foam as a decoupler DOES make a difference.  The bass is even more precise.  You can really crank up the music and everything is tight and controlled.  It is also noticeable when using test tones...

These B200s do like power!  I had them up loud before and they keep it together under pressure. :o

I need to try your idea about the one-wing + side wall...

Thanks,

Vinnie

Dmason

  • Full Member
  • Posts: 1283
Re: Gravity Well Of A DarkStar
« Reply #1093 on: 30 Aug 2006, 01:19 am »
....or two wings and the side wall.

I am not at all surprised the gasket makes a difference. It seems that strips of metal could quite easily find a way to resonate at their secret frequency, given enough amplitude. Metal is good at that.

As for power and B200, I used mine with a Hafler 9505, 250 watt A/AB monster for awhile, and the B200 really, really love all that current, and can sink buckets of power without ANY trouble at all. They sounded really sweet with the Class A TransNova circuit in place. With DSP in place, you can pull down the rising Fr to EQ the bass, and get tons of bass on OB. At least it sounded like bass, despite all the quasi-science to the contrary :thumb:

opnly bafld

Re: Gravity Well Of A DarkStar
« Reply #1094 on: 30 Aug 2006, 03:22 am »
At least it sounded like bass, despite all the quasi-science to the contrary :thumb:

Maybe it was just SLOOOOOOW TREBLE. :lol:

Lin

-Richard-

  • Full Member
  • Posts: 853
Re: Gravity Well Of A DarkStar
« Reply #1095 on: 30 Aug 2006, 03:58 am »
Hi BrassEar ~

Your question is not only important but it points to the strange incredulity of the entire
Open Baffle phenomena ~

Several years (light years) ago I was involved with Dmason and several other AC members
in investigating digital amplification which seemed so promising and finally found
sublime resolution in Vinnie's Signature 30... a more gorgeous sounding SS amp does
not exist!!!

During that time I had a pair of Maggie 1.6's... and like you, BrassEar, I was in love with them!

Maggie's give you an enormous slice of what dipole sound is all about... fast, transparent,
detailed, rich tonality, all-in-all a very alive sound space... everyone who heard my 1.6's
was extremely impressed... and Deb loved them as much as I did!!

Also during that period Dmason was moving through various speaker designs with an escalating
appetite for trying on everything of value that was available... at least within a reasonable
price range... our correspondence became more fascinating as Dmason articulated his
experiences with his speakers... at some point Dmason began to grasp an overview of
everything that was out there in speaker design... he research broadened and deepened
and he began to penetrate the "underground" and DIY information resources ~

At some point Dmason discovered Open Baffles and the Visaton B200 which was being
explored in Germany and other places... he built a simple baffle based on the then current
understanding of what was working best and he became incredibly excited about it and
suggested I try it myself ~

By that time I had been corresponding with Dmason long enough to realize that he had
an extraordinary talent for hearing where the magic was in audio... the fact that Dmason
studied classical piano in college, played in a successful rock band for many years, and
had experience building his own audio gear, gave him a tremendous pool of experience to
draw from ~

I jumped in just for the fun of it... and what I discovered has utterly changed my thinking
about audio's potential to deliver a musical event intact... with all the life and energy
that was there in the original performance ~

So let me see, Brass Ear, if I can point out what you will be hearing with the B200 OB's that
the Maggies did not do for me... just to give you some sense of what the B200's are actually
doing: the Maggie's are wonderful... but they still sound as if they are a lens between
you and the music... a window if you like... clear to be sure... but compared to the OB
experience the Maggie's seem a tad recessed within the fabric of the speaker itself ~

In the end the music cannot quite break free of some kind of restraint that is built into the
speaker design... we are speaking of a certain uncanny spatial resonance here ~

The OB experience is very different... what I am hearing has nothing about it that is mechanical...
it is not real of course... but that is not the way it sounds... IT SOUNDS REAL!!!!!!!!!!

Fully alive and intact and organic and filling the listening space with tremendous energy and
a palpable presence that is completely 3-dimensional ~

I do not think this is achievable without some kind of modification... I am currently using
my pair of Bipoles behind my OB panels cut off at 150 Hz to supply some lower frequency
presence... and that has snapped the whole thing together for me... what I am hearing with
this combination is no longer hi-fi... it is real-fi... a total immersion in the musical space...
it has become so powerful an experience that it is no longer CD dependent... CD's that seemed
weak... or simply unlistenable for one reason or another... now pulsate with life and intelligence...
and I am using the cheapest mass market CD player imaginable... and cheap wire from Lowes ~

Now Brass Ear, some experimentation is needed here... after all I am talking about a level
of sound that should cost (if one wants to think is these terms) perhaps $20,000 to $30,0000.
So for less than $500 in drivers and material you have to expect some trial and error in order
to achieve a maximum implementation of this really incredibly phenomena ~

But for me it is an utter revolution in my audio thinking... I hope this helps ~

Warm Regards ~ Richard ~
« Last Edit: 30 Aug 2006, 07:02 am by -Richard- »

JohninCR

  • Full Member
  • Posts: 947
Re: Gravity Well Of A DarkStar
« Reply #1096 on: 30 Aug 2006, 05:34 am »
Dan,
I'm surprized that you'd egg on the mob like that, unless you are
getting ready to sell something.  Quasi-science indeed.  I bet you
didn't say that when you met with Mr. Linkwitz, and you know that
all my stuff related to OB bass is directly from his technical info put
into laymen's terms.  Did you get a chance to listen to his Orions
while you were there?  Did you ask him why he uses 2 10's and plus
a sub at the very bottom, when he could simply use a B200 and
get "tons of bass"? :thumb:

What pray tell is the reference to using your Hafler?  Headroom and
plenty of current on tap is great, but we all know that throwing more
than a handful of watts at a B200 running full range on OB is going
to send it into over-excursion unless you're playing something like
violin solos or other music with little content below 60hz or so.


John,
I don't know what you're laughing about.  You added an extra driver
to help with the bass, and you'll be adding more later too, once you're
on to your next greatest thing since sliced bread.  BTW, not once have
I said that I didn't like the B200.  I wouldn't have purchased a second
pair if I didn't.  I'm just realistic in working around their compromises,
and all drivers have compromises, especially once you talk about freeing
them of their boxes.


Bjorn,
Don't give up so quickly on your beautiful baffles.  Even small wings
on relatively narrow baffles can form surfaces of reflection if you don't
address the issue.  Now that you've heard the difference, just tweak
it out.  Plus, you need the extra material to create an appropriate
round over at the baffle's edge.  A recent topic elsewhere indicates
that edge diffraction is twice as much of an issue with OB's than
with boxes.  This supports my personal results in this area, and it
means that unless you use about a 4" thick baffle there's no way to
address it with a flat baffle.  Even then you'd still have to address
the "closed in sound" resulting from the driver cutout.  Add edge
diffraction to my list of why OB's are considered to not image as well
as small boxes.

If you give up the structural rigidity your current wings give you,
then you'd be introducing a new compromise unless you go with a
magnet mount and isolation from the baffle, for which Nigel (OldTimer
here) sets a great example.  Bracing and damping will clear up the
resonance issue in your woofer section.


Scorpion,
I agree that SL could improve the Orion's construction, but the only
change I'd make which is related to side panel depth is to get rid of
that lip on the front side.  The only reason I suspect it's there is for
the grill cover, so that's a conscious form over function decision.   I'd
also address those little backside wings for the mids, which  act as
reflection points and add significant bracing in the woofer section.  He
talks about matrix bracing needed every 4" or so in his literature, but
completely forgets it on the Orion.


Sure the B200 and a handful of other drivers can sound great all alone
on a largish flat baffle, and even provide a reasonable amount of bass.
However, we mustn't lose sight of the fact that the most DIYers are
under the false impression that large baffles are a requirement of OB's.
This is the most common excuse for not trying something so simple.
Without additional drivers, the only way around a large baffle is to use
wings, but with wings a number of other issues come into play.  If you
address these issues properly, then you can retain the sonic advantages
of flat baffles and enjoy some key audible advantages over them.

Polarbear

Re: Gravity Well Of A DarkStar
« Reply #1097 on: 30 Aug 2006, 07:15 am »
Thanks John, for taking the time to comment on my (and other) findings.


Bjorn,
Don't give up so quickly on your beautiful baffles.  Even small wings
on relatively narrow baffles can form surfaces of reflection if you don't
address the issue.  Now that you've heard the difference, just tweak
it out.

I would not be removing the whole wing, just remove the material around the widebander making the wing. Like it would be a flat baffle up there. Down by the woofersection it would remain the same. How would you tweak it out if not removing the wing?

Quote
  Plus, you need the extra material to create an appropriate
round over at the baffle's edge.  A recent topic elsewhere indicates
that edge diffraction is twice as much of an issue with OB's than
with boxes.  This supports my personal results in this area, and it
means that unless you use about a 4" thick baffle there's no way to
address it with a flat baffle. 

I did not quite get this. Extra material where?

Quote
If you give up the structural rigidity your current wings give you,
then you'd be introducing a new compromise unless you go with a
magnet mount and isolation from the baffle, for which Nigel (OldTimer
here) sets a great example. 

I would not give up the structural rigidity. The wings will be there, but not as deep.
I am also planning to decouple the driver from the baffle, but in another way by clamping the the driver between felt and wood.

Quote
Bracing and damping will clear up the
resonance issue in your woofer section.

How would you do that?`


Cheers

Bjørn  :thumb:

Russell Dawkins

Re: Gravity Well Of A DarkStar
« Reply #1098 on: 30 Aug 2006, 07:30 am »
The PHY in my OB just didn't cut it for me and after about an hour of sampling different tracks, I couldn't take it anymore and put the B200s back in and EVERYTHING sounded so much better  :singing:

Note -- This is NOT my impressions of the Auditorium 23 Solovox, which uses a very similar looking PHY (it is actually an OEM driver with a different voice coil and a few other mods I believe I read).  The Solovox left me very impressed after listening, and left me wanting to hear more of it and to learn more about the design.  It is a fascinating design IMO!  :idea:

Thanks, Vinnie,
I am getting the picture that the 8" sounds better than the 12".
I wonder if the 8" in the Solovox is maybe the silver voice coil version and you heard the copper.

I have often wondered which version of the 8 sounds better. I notice the specs are identical for both, except for power handling, which is listed as 15 w for the silver and 25 w for the copper. The performance charts (frequency response and impulse response) are not similar, they're the same charts!

« Last Edit: 30 Aug 2006, 07:40 am by Russell Dawkins »

JohninCR

  • Full Member
  • Posts: 947
Re: Gravity Well Of A DarkStar
« Reply #1099 on: 30 Aug 2006, 08:10 am »
Bjorn,

You can try a triangular wedge that extends from the rear edge of
the wing to the baffle cutout.  Then instead of the rear wave expanding
and reflecting off of your wings, it will expand smoothly (like with a flat
baffle) from when it leaves the driver until it clears the baffle.

This will give you plenty of material thickness at the corners to do large
radius roundovers on the front.  Also round over the rear edge of the
wing using as large a radius as possible.  The reason I believe this is
more important than for boxed speakers is at the sides of an OB, the
air molecule movement is greater and faster than a box.  As the waves
expand around the edges of the baffle one side has a pressure and the
other a rarefaction, so the molecules will rush toward the rarefaction.
Then as the wave progresses 1/2 wavelength the pressure and rarefaction
are opposite, so the molecules rush back.  The reason this velocity flow
is greater with OB's is that you have 2 separate and opposite wave sources
meeting each other.  With a box you have just the back and forth movement
from one source.

The smoother the curve of the surface that this back and forth movement
travels around, the less turbulent the flow and less disturbance in the
waveform expanding from that area.  I think this is more important with
narrower baffles vs big baffles because the bending around the baffle begins
to occur at higher frequencies, where imaging information is more crucial.

Resonant sounds in the bass region can have multiple causes.  Play some
bass heavy music and feel for panel vibration, which bracing can help to
correct.  Damping on the interior side of the panels can also help damp the
panel vibrations.  You may also be getting some cavity resonance, which
is easily cured with polyfill in the rear cavity.

If you implement any of these strategies, please share how they work out.