[-Richard-]

Hi Pardales ~

Congratulations!!! Lowther's have a wonderful reputation and in a very real sense they
have stood the test of time as one of the essential "full-range" single-driver speakers ~

There is perhaps something of a similarity to all incredibly fast, high efficiency wide-range
speakers... taking that into consideration, I suspect that placing a Lowther in a ported box
must sound something like the Omega boxed speakers that use the B200's... truck loads of
detail and a very coherent sound space... perhaps with the addition of the second top
firing speaker the Ambience do in fact create a more "ambient" sense of space...
which must sound very satisfying indeed!!

This Open Baffle thread is for the adventurous, and/or audio lovers on a very tight budget
who are interested in finding out what can be achieved by completely liberating the drivers
from the box entirely... it turns out that boxes and drivers do not get along with each
other very well... there are a myriad of problems that using a driver in a box creates ~

For example: the back wave must be essentially surpressed and absorbed so it does
not re-enter the speaker cone where it will "cancel" similar frequencies in the front firing wave...
there is also the pressure build-up in the box that must be dissipated so it does not distort the
cone as it moves through its excursion... and then there are potential resonances in the
cabinetry that create frequency anomalies, exaggerating certain frequency segments ...
and ported boxes, while they can be tuned to allow some of the lower frequencies to be
pushed a bit lower than the driver is able to reproduce by itself (thus adding more "bass")
are not always as refined in sound as what the driver is producing, causing yet
another "distortion" in the all-over sound... then there is the way boxed speakers load
the room... essentially all boxed speakers "beam" their information in a radiating pattern
that is limited by the box itself... and to make matter even worse, this limited radiation
pattern interacts with the room in a way that stimulates room node anomalies... again,
further exaggerating certain frequency segments... there are ways to get around this
somewhat, like introducing rounded corners on the front of the baffle, for example...
or the use of a second driver on top, to load the room "indirectly" as in your Ambience speakers ~

As you can see, speaker designers who create box speakers have huge problems
facing them when they start off to design a box speaker that they somehow must try to
get around ~

And to get around these very real issues they use various strategies to "compensate" for a
design strategy that never actually solves some of these essential problems ~

Open Baffle speakers start off by throwing away the largest problem that boxed speakers
have... the box!!! ~

It turns out that any driver loads a room better without a box than in a box!!! and drivers
in Open Baffle speakers load the room in such a way that actually avoids many of the
room interactions that boxed speakers stimulate ~

And of course... the expense of this essentially DIY project is much lower than a boxed
speaker... which makes experimentation worthwhile ~

I have shared this information with you, Pardales, so that perhaps you can get a sense
of why someone might spend some time to wade through this admittedly lengthy thread
to try and make sense of where they could begin to get involved in this phenomena ~

Most of us do not have the highly developed skills of a good cabinet maker... but most
of us can have a simple baffle cut by the local Lowes or Home Depot and then cut a hole
with a jigsaw when we get it home to fit a B200 in, so we can get an idea what all the raves
are all about on this thread ~

It is all about learning what is possible with home sound reproduction... this learning experience
is what this thread is all about... and what Dmason had in mind when he started it... what
one learns with Open Baffle speakers can be applied to ones speaker choices for the
rest of our lives... it is that important!!!

Best of luck with your new speakers ~

Warm Regards ~ Richard ~

[pardales]

Thanks for the kind replies. I have no doubt that there is much for me to learn here. At some point I will read back through this monster thread. I tend to jump in first and then hope I can swim.....These are my first single driver speakers. One of the neat things about these is that I can turn off the ambience driver via a switch on the back. I would have loved to try the open baffle style but after a brief discussion with someone who knows something about open baffle designs it was determined that my room would not be conducive to some open baffle design (given where I have to place speakers, it does not leave me much room to manipulate the wings--so I went with a ported box).

Maybe someday I will be able to try an open baffle. For now I have become a single driver speaker lover!     

[scorpion]

MarkC,

I am now playing with a carefully calculated BSC-circuit consisting of 8 ohm MOX in parallell with a 1 mH inductor in the signal lead.
So far absolutly the best. Very good in fact !

/Erling

[markC]

Scorpion;
I'm most interested in your experiment. Please keep us informed. I've had a bad weekend with my baffles, applying varnish to the cork reacted with the "super 77" spray adhesive and the seams started coming apart. Now it's contact cement to the rescue and wait and see. Thinking out loud here, I'm inclined to implement a notch filter which will tame the 2k to 4k octave. Just initial thoughts, mind you, and the passive components seem to be fairly unobtrusive. Can't remember off hand, but I think something like a 0.6 mh coil, a 4 ohm resister and a 3 uf cap. I would definitely have to re-check those values, as they are from memory before my cork began to peel and cause me grief. Super 77 my ass. Water base varnish, (in hind site), would be the way to go. Oh well, if the baffles go for a shit I'll burn them and build a pair slightly larger out of Russian birch ply. By the way, what is a MOX?
After checking the values of the components, it looks more like an 8 or 10 uf cap with a .25 mH inductor and a 3-4 ohm R  which may cause some phasing issues.

[scorpion]

markC,

MOX is a metal oxide resistor. I am experimenting further and no doubt I will be successful. I have
introduced a Zobel network and played around with resistor and inductor values. I have learnt a bit by looking at
Visaton's filters that they have on their Web.

I measured response today with my SPL 1 m from the right speaker, left not playing, and I have now a response of
+ - 5 db from 40 to 10000 Hz indoors. I am bound to agree with Wind Chaser that the B200 do not lack bass at normal listening
levels. But I think I have lost a bit above 10000 Hz, just the tiniest bit, it may be the price to pay.

Best of all, when I have got that balanced result now that I have aimed at, suddenly the whole presentation falls in place.
I just have a fabulous soundpicture now. Presentation in the sweetspot is almost physical, especially vocals are so
realistic that you do not quite think it is true (with good sources). Amazing. Probably the best I ever heard. I can hear the magic
of this speaker now.

Bass is helped by the short distance to the floor only 40 cms (16 inches). I'll go on with permanent baffles for the B200s and report
when I have progressed further. 
/Erling

[-Richard-]

Hi Erling ~

You are most certainly hearing what we are hearing... congratulations!!!!!

You experimented based on your "intuition" of what is possible... and that is what
this thread is all about... each of us seems to have found a method that works!!!!

And the result is WORLD CLASS SOUND FOR A PITTANCE!!!!!

Let me be so bold as to suggest that the more you listen the more you will find
yourself falling into a permanent state of amazement... Deb and I are listening to music
this morning and just like each and every day we listen, we are  TRULY AMAZED!!!!!!

The voice and instruments are free to live in our listening room...  UTTERLY FREE!!!!!!

Please keep us informed of your insights ~

Warm Regards ~ Richard ~

[JeffB]

scorpion,

Is the 16 inches measured from the floor to the bottom of the B200 or to the middle of the B200?

[scorpion]

JeffB,

To the middle. There is also a 10 degree backward slope.

/Erling

[lizardBrain]

Hi all. Been lurking around here for a while and have built a couple of versions of the B200 OBs (with and without wings). Although it has been said before, I just want to give thanks to all of you for sharing your ideas and knowledge and allowing amateurs like me to stand on your shoulder and have some real fun with this hobby.

I have a question for Richard. I noticed in one post you said that you are using a simple coil to "crossover" at around 150 to bipoles. I am interested in something similar. I have some 15" woofers sitting around that I would like to integrate into a simple baffle, 4'x2' approximately (Ala Jamo). Two per side with a simple coil. I was just wondering how this setup was working for you and if you had any pictures and what advice you had.

Thanks,
Matt 

[opnly bafld]

Welcome Matt,
My $.02 FWIW.
A good thing about using an inductor is the gradual rolloff helps fill in the upper bass.
A potentially bad side is not many drivers playing that high will integrate well with the B200 IMO.

My best advise is try it and see if you like.

Lin

[lizardBrain]

Thanks Lin
What are the characteristics of a woofer that would determine if it would integrate well with the b200s in that range?

Matt

[opnly bafld]

Matt,
The two main specs to look at are qts and fs.
Qts should be at least .5 and a higher number (closer to 1+) will produce more OB bass.
Unfortunately, even though specs help, they don't tell you exactly how a given driver will sound.
You might want to start a new OB thread, asking what woofers have been tried with B's or what people have used to augment the bass.

Some, myself included, have used 2 B200s this way (lower one very close to the floor) with good results.
This allows more options, IMO, of what to use for lower bass.
I think some are content with just the 2 B's.

Currently, I am trying out 2 B's, top and middle, in a 1.5 way with an inductor on the lower driver (roll off starting at 80hz @6dB/oct), and a Hawthorne Audio 15" Augie on the bottom at 80hz 24dB/oct.
I had the HA 15" before I tried 2 B200s and I didn't feel it integrated well using it up to the 100hz-300hz range with the coil.
Now just using it in the 100hz down range it sounds much better IMO.

Hope this helps,
Lin

[lizardBrain]

Your advice is much appreciated.

The woofers I will be trying out have an fs of 36 and a qts of .88 (and xmax of around 3 I think) , with a sensitivity of 100. I am looking forward to seeing how they integrate in with the b200. I like the wings, but I can't use them at this time with a 1.5 year old and a 2.7 year old poking everything (I have already lost one 92jxs from my triangle mltl. I don't want to talk about it ) So, I am going with just a straight baffle.

I will report back.

 
Matt

[-Richard-]

Hi Matt ~

I am glad you have felt sufficiently adventurous to begin to experiment with the B200's
in OB... welcome to the journey ~

I feel I can safely say that what you will be learning about the potential of this potent speaker
paradigm will cast its spell on you for the rest of your life... so that all your future speaker
choices will be deeply affected by the amazingly sophisticated level of music reproduction your
OB's will be offering you ~

You are searching for an enhancement of your OB experience with the use of drivers that can
integrate the lower frequencies seamlessly with your B200's... that seems like the logical next
step after getting to know what your B200's alone sound like... several people have contributed
to this thread with their versions of what they think is the best approach to this... and their
solutions are based perhaps on the music they listen to, their amplification and also perhaps
the size of their room ~

Separate sealed subs, 2 B200's per panel, EQ devices, subwoofer-drivers attached to the lower
area of the OB panels, wings, the position of the drivers on the panels, the relative distance of the
panels to the back wall for its bass reinforcement, are all valid possibilities that are being tried
and that seem to work effectively with the B200's in OB ~

There are some contributors to this thread that feel that dipole bass is by far superior to bass
created in any other way: they cite better seamless integration and a "purer" OB sound...
perhaps less visceral bass energy in absolute terms but more realistic and with better detail ~

I once tried a sub that was nicely worked out with a plate amp and nice controls including an
option for simple but effective EQ'ing and was not at all impressed with the results... it added
nothing to the all-over sound of my OB's and Deborah felt it lacked "musical" vitality... I agreed!!!

I tried Dmason's suggestion of using 2 B200's... the lower one merely inches from the floor and
that worked very nicely for a great deal of music... however in my room with my amplification
choices I found it a tad light on the bottom ~

Then merely for the sake of experimentation I hooked up a pair of Bipoles to the top B200
drivers in parallel using a simple coiled copper inductor which can be purchased from Parts
Express rather reasonably: click on the link below to see what they have:

http://www.partsexpress.com/webpage.cfm?DID=7&WebPage_ID=3&Start=5&Filter=Jantzen%2Binductors&searchorderby=1&sm=1&so=1&search_type=main&desc=ASC

I have 2 pairs... one that cuts off at 100Hz and one that cuts off at 150Hz... I am currently using
the pair that cut off at 150 Hz... here is how it works... a positive lead from the speaker cable
wire from each Bipole speaker is attached to the INSIDE prong of one inductor (the coiled inductor
has 2 prongs... one that "starts" on the INSIDE of the coil and one that ends at the OUTSIDE of
the coil... just like a bale of wool or roll of string) the positive lead of the speaker cable wire
from each B200 driver is attached to the OUTSIDE prong of one of the inductors... the neutral leads
tie together... what you have done is spliced the inductor "in-between" the speaker cable wire from
the B200 to another set of drivers ~

to many this will seem like a simplistic temporary solution to the bass reproduction issues that
a single B200 driver in a panel seems to present ~

Actually, the sound I am getting is truly fantastic... Jim McCarthy, who built my OB panels and is a
composer, song-writer, recording engineer was amazed to hear the effect this simple combination
created... he admitted: "I thought the sound of the single B200 was incredible but this is really
much better... tonally rich and very palpable in-the-room presentation!!!"

I used to think that what I wanted most was a fully transparent sound that I thought electrostatics
came close to realizing... except that I never was convinced by the lack of dynamics that seemed
to be an inherent problem of electrostatics... not anymore... I am thrilled to hear a slightly more
opaque sound that the Bipoles introduce because combined with the B200's they create
an amazing REALISM... THE SAME REALISM THAT YOU HEAR AT A LIVE UN-AMPLIFIED CONCERT ~

Dmason is experimenting with horn speakers that he feels comes "dangerously" close to sounding
as good as Open Baffle speakers... and for all their simplicity of build are able to generate
sound down to 30Hz that according to the good doctor "sound exactly like dipole bass... incredible" ~

I intend to pursue the good doctor's RX for deep dipole-sounding bass from what he describes
as "a very tall flute with a small footprint"... perhaps Dmason might be swayed to re-enter his
Dark Star thread to share some of these ideas with everyone... or perhaps he may be tempted
to start another thread that deals specifically with this simple but apparently devastatingly effective
DIY horn speaker paradigm ~

Let us know of your findings, Matt... so we can all learn from your experiences!!!!

Warm Regards ~ Richard ~

[lizardBrain]

Thanks Richard:

I am however a bit confused by this description:"I have 2 pairs... one that cuts off at 100Hz and one that cuts off at 150Hz... I am currently using
the pair that cut off at 150 Hz... here is how it works... a positive lead from the speaker cable
wire from each Bipole speaker is attached to the INSIDE prong of one inductor (the coiled inductor
has 2 prongs... one that "starts" on the INSIDE of the coil and one that ends at the OUTSIDE of
the coil... just like a bale of wool or roll of string) the positive lead of the speaker cable wire
from each B200 driver is attached to the OUTSIDE prong of one of the inductors... the neutral leads
tie together... what you have done is spliced the inductor "in-between" the speaker cable wire from
the B200 to another set of drivers ~"

Can you, or someone, draw this out?

Thanks

[-Richard-]

Hi Matt ~

It would be wonderful if I knew how to download a picture for you... the truth is I don't
know how... if someone would care to explain to me and anyone else who might be interested
how to download an image to this or any other AC thread that would be most helpful ~

Let me try to explain again how the inductor "splices" into the speaker cable that goes from the
B200's to the Bipoles and see if I can write a bit more clearly:

I am using a pair of cheap Lowes speaker cables that goes from my amp to the
top pair of B200's in my OB panel... the bottom driver is not being used right now:

I also have another speaker cable that goes from the same top drivers in my OB's
to my Bipoles: in effect one amp is driving the B200's and the Bipoles:
so that the speaker cable goes from the amp to the B200's and then from the B200's
to the Bipoles... I believe connecting the B200's and the Bipoles this way is considered
a parallel connection:

Spliced into the speaker cables that go from the B200's to the Bipoles is an inductor:

So let's think about the speaker cable that goes from each B200 to each Bipole for a moment:
spliced into that cable is the inductor... so there is speaker cable on both sides of the
inductor... one side is coming from the B200... the other side is going to the Bipoles:
both of these "sections" of speaker cable (coming to the inductor and going from it) are attached to
the inductor by using the positive leads only... one "positive" lead from each section of cable attaches
to one of the two prongs of the inductor (each coiled inductor has 2 prongs... sticking out at each end
of the coil)... the neutral lead wires of each section of wire are attached to themselves...
not to the inductor ~

I hope this makes sense ~

Let me know, Matt ~

Warm Regards ~ Richard ~

[Wind Chaser]

.
Not quite what you'd call a picture, more of an illustration...


A  + + + + + + + +          + + + + + INDUCTOR + + + + + + +
M                                B200                                                                BASS
P  - - - - - - - - - - -          - - - - - - - - - - - - - - - - - - - - - - -
L
I
F
I   + + + + + + + +          + + + + + INDUCTOR + + + + + + +                           
E                                B200                                                                 BASS
R  - - - - - - - - - - -            - - - - - - - - - - - - - - - - - - - - - - -


The ERSE Super Q inductors cost about 1/3 of the Jantzen and have a much lower DCR.

http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=266-946

These will equate to a 6db roll off at 100Hz in a 6 ohm load.


John

[lizardBrain]

I've got it now. Thanks for your help.

[mcgsxr]

Here's my latest rendition, a b200, plus a Mach 5 Audio 12 inch woofer, per panel.

Better bass, more vibrations, exactly as those in the know predicted.

My next step includes exploring the vibration solutions (thicker panels, air gap around the woofer in a separate panel), and the possible addition of a 2nd 12 per panel...

Oh, and for those looking to explore open-baffle speakers, we have a new circle dedicated to this here on AC, have a look, and join the fun!  Should end up easier to post new queries, and find out information, vs searching through this exceptional thread.

http://www.audiocircle.com/index.php?board=90.0

[Vinnie R.]

Hey mcgsxr,

Nice work in that basement bunker! 

Are you using a separate amp for the 12 inchers?  Active or passive X-over?

Thanks,

Vinnie