[JohnCZ]

Hi All,
Finally got a day off to show off and post my Open Baffle Build with the Tang Band 1808. They originally started out with the Visation on a 3 panel adjustable baffle. Right off the bat I was hooked with the open baffle sound. Not much bass but with certain music it was very nice. I had no room to put a bass module in the room so I went with the single baffle you see in the pics.

Started with Visation and added the Alpha 15. I tried to adjust the balance with the T-Bass filter someone here suggested and it worked ok, but using the transformer and a lot of parts - I wanted to get back to simple and less components. I was not totally satisfied with the Visation on all types of music and felt it had a peak that bothered me. Heard quite a bit about the Tang Band and I'm much more pleased with the overall presentation.

There's obviously more in the photo - a SB tweeter. I've experimented with it just to add some air to the Tang Band - still trying to decide for sure, but I'll probably keep it.

The baffle is a multi layered baltic ply piece. The bottom half with the Alpha 15 is a composition of 3 layers of baltic ply and the upper half, 2 layers. The base is the same material - about 2 inches thick. Side panels are 3/4" baltic ply.  The baffle still needs to be finished but its also a work in progress - along with my wiring!

I do have a question from the experienced builders that have used the Tang Band.  I do have a very slight peak on certain music. I am running the Tang Band without filters - full range. On the Alpha I have a 0.8 mh coil and a 6.8 uf cap.  Someone recommended a .9 mh coil but at the time I only had the .8 mh on hand.  The tweeter has a 2.2 uf cap.

Now that the drivers have a couple of hundred hours on them I would like to tweek the filters and possibly reduce that slight peak in the Tang Band. Anyone have recommendations as to what they have successfully used? Will upgrade the coil on the bass to a steel laminate inductor too.

Amp information:
Currently using the Vista el84 integrated and it is great. I will be picking up some NOS RCAs for it next week. My supplier also has Mullards - would they be worth the extra money?
Previously I had been using a vintage Fisher X202B that was amazingly good. Its now in the shop repairing some bad controls, tone, etc.

I also had the opportunity to get in on the TBI MG3 tour and had that amp for a couple of days. I would have purchased the amp on the spot if it had at least 2 inputs. Very close to the Vista in its presentation.

I've also used a vintage 20w ss Yamaha receiver with good results for a non tube amp.

I do want to thank the many members of the Forum that helped me along the way including MJK, Richard, opnly bafld, scorpion and mcgsxr in particular.

[-Richard-]

Hi JohnCZ ~  Your Open Baffle speakers look wonderful. I am very impressed. You seem to have constructed it with all of the essential structural elements, that as a community, we have learned and shared with each other.

What seems clear to me now... and this will probable sound controversial... and perhaps even nihilistic... is that any form of 'corrective' circuitry applied to 'taming' a drivers frequency anomalies extracts from the all-over musical presentation that magical sense of 'live'... that sense of hearing something that has a quality of spontaneous 'presence' that brings the music to life... and instead replaces it with a generic-like smoothness.

I mention controversial, because this goes against our usual 'problem-solving' approach that says, if there is something 'wrong', then fix it. The problem here is that fixing-it means also extracting from it the very quality that helps to give it a sense of life... that pulls one into the musical presentation because of this impossible-to-define sense of aliveness that is there when no form of corrective circuity (surgery) is allowed to interfere with it.

I am not necessarily talking about using parts, like inductors, to cut off upper frequencies from bass drivers, so that the wide-range drivers can function naturally to its lowest region... and the same would apply to tweeters regarding their lower frequencies. I am referring to 'correcting' or filtering things like your Tang Band's upper frequency emphasis.

If we allow ourselves to take this approach to its logical conclusive then we have only one alternative, to find a driver that works without any form of filtering. That is where I find myself now, looking to see if such a driver actually exists for our application.

For example I was dismayed to see the other day that Lowther America is using some form of ribbon foil or planar tweeter in their new Open Baffle set-up... creating a 3-way with their Lowther Alnico and a bass driver. To me this is an admission that they believe that their 8" full-range drivers cannot resolve the upper frequency sense of air and space that sophisticated audiophiles are looking for.

In contrast the Indian designer of Rethym speakers, Jacob George, after years of struggling to 'correct' the anomolies presented by Lowther drivers in his beautifully designed 'horn' style speakers, decided to design his own wide-range drivers that perfectly suit his design. Although he uses some of the re-directed back wave to augment the wide-range drivers presentation (like all inner-horn baffles) and also uses modest bass drivers to fill in the lower frequencies not covered by the full range driver, just as we do with our Open Baffle designs, there is no filtering of the wide-range driver needed. The result is that his new Rethym designs are received with incredible acclaim. There is no filtering to rob the drivers of that sense of aliveness.

I mentioned nihilism before, because I honestly feel that we may have taken our Open Baffle experiments using cone drivers as far as we can in terms of the baffles structure. It is the drivers themselves that seems to be holding us back from enjoying the ultimate sense of 'freedom' from frequency anomalies that detract from our pleasure.

If we wish to continue working with cone drivers, I think we are now looking for that rare one that will deliver the goods perfectly without any need for filtering... if we want the ultimate sense of aliveness. I am just thinking out-loud here.

I do not want to use a 3-driver solution if that is possible. Just for the sake of my 'personal' design aesthetic which does not like complexity. I love simplicity. passing off different frequencies to different drivers like Lowther seems to be now doing with their OB's, based perhaps on Choppers design solutions, is unacceptable to me... at least for now.

I don't want to give up trying to find a wide-range driver that will work in a 2-way OB design.

Thanks, John, for sharing your wonderful OB designs and experience with us. I deeply appreciate your work and insights.

With Warmest Regards ~ Richard

[exspec]

While Lowther utilizing HF augmentation in their design is an admission of sorts that there is some benefit to be had... I would also suggest this may be more market driven. It's not a written in stone admission of guilt. There have been plenty of companies who have come and gone because they tried to tell customers what they want rather than selling them what the customer wants. There isn't a day that goes by someone doesn't knock Bose speakers... but the reason they are around still is because they built products people wanted. This is not to say Amar Bose knew nothing about sound or electronics. Before I bought a full range driver, I had heard it all "no enough bass, not enough highs" and that sort... if that is enough to deter some potential buyers, adding a tweeter to a design while the company really feels it "isn't necessary" is totally logical from a marketing standpoint.

To the OP... I have a Visaton B200 and am certain it doesnt hit 20kHz like a dedicated tweeter, and am pursuing adding a tweeter or employing a two-way mid-tweet in my system and removing the Visaton altogether. I would say the major benefit to a FR driver is that the crossover moves out of the more critical range. Your orchestra recording may have been recorded with only 2 mics, but there may have been 40 sources of sound those two mics were picking up. So having 3 devices on your end reproducing all of those sounds seems to make perfect sense to me. As for the filters, I use none, just an active crossover. I am sure there is much to be gained through the use of filters, especially when dealing with less than optimal conditions, but am attempting to use as many design parameters as possible regarding the driver, baffle and their setup before using any filters. It is my hope that getting most of it dealt with this way will eliminate the need for excessive signal alteration.

Adding duct seal to deaden the baskets made a difference in the performance of my Visatons... as did bracing the magnet.

[matevana]

What seems clear to me now... and this will probable sound controversial... and perhaps even nihilistic... is that any form of 'corrective' circuitry applied to 'taming' a drivers frequency anomalies extracts from the all-over musical presentation that magical sense of 'live'... that sense of hearing something that has a quality of spontaneous 'presence' that brings the music to life... and instead replaces it with a generic-like smoothness.

Richard,

Your assumption is just not true my friend. You imply that any type of tank circuit robs a driver of presence and prevents it from bringing music to life. No driver is linear both on and off axis and the best speakers in the world make use of some type of correction, separate from limiting frequencies. I can pretty much assure you that I can measure and correct a driver which you would prefer in a blind test over the same unaltered driver at the same relative loudness. People often mistake loudness for presence and are opposed to any component that lies in the signal path. Of course they subsequently complain about things like driver shout and off axis linearity. Speaker design is based on establishing priorities, considering your environment and in many cases, compromise.  There is no free lunch. 

[mcgsxr]

Looks like a great project, and I love that you shared the history and development of how you explored and refined along the way.

That part, to me, is the critical part.

It was Dmason all those years ago that spurred me into experimentation with OB, and ultimately the b200 Visaton.

I feel that given the differences in rooms, musical preference, and how we listen (volume, what we key in on in a piece etc) there are so many different and satisfying ways to build a speaker that you can live with.  I tried bsc type circuits with the OB speakers I built, and did not like what they brought to the table in my system for my ears.

I lived with ported monitors for 10 years, then OB Visatons for another 7 or so.  Totally different experience, but both ultimately took me away from daily life and gave me a satisfying peek into the music.

I am currently without a dedicated 2 channel setup, living with a good HT system that I built up for my basement when we finished it earlier this year.

I am also on the hunt for the next project, but WAF has worked into the space given it is now attractive to others to come to!

Again, a well constructed and thought through implementation and thanks for sharing the pics, I love it!

[-Richard-]

Hi Matevana ~

"Your assumption is just not true my friend."

What I shared with the OB community is just my observation, based on having played around with a few different drivers and circuits.

It is not an 'assumption', in the literal sense of that word... which means an idea that is preformed... that has no actual observation or experience behind it, like an opinion.

However, my experience is limited and you may very well be right, that a well-done circuit used to 'tame' a drivers frequency anomalies (peaks and/or valleys) is entirely possible without affecting its sense of life.

Your suggestion that: "People often mistake loudness for presence", is indescipherable to me. I have no idea what you mean by "presence" used in the context you describe here, relating it to loudness.

I am not certain I can adequately describe 'presence' as I used it in my post. For me it is an effect that goes beyond any one quality that can be named or accounted for in 'measurable' terms. It is a sense of 'aliveness'... or perhaps the illusion of "aliveness" and "there-ness" that allows the mind to feel that the music has a spontaneous life to it... that it is not merely being mechanically reproduced.

If what I just wrote does not mean anything to you, there is no problem at all. For me it is an affect that seems to bring with it an enormous pleasure to the music I am listening to.

With Warmest Regards ~ Richard

[planet10]

I don't want to give up trying to find a wide-range driver that will work in a 2-way OB design.

You may want to look at the new Mark Audio Alpair10p.

dave

[planet10]

As for the filters, I use none, just an active crossover.

An active XO IS a set of filters.

dave

[-Richard-]

Hi Dave ~

Strangely I have been meaning to contact you recently. There was a question I had for you that at this moment eludes me.

Thanks for the heads-up on the Mark Audio Alpair10p. I saw that Madisound is selling it for a little over $100.

Have you had a chance to hear it in an OB application, Dave?

Yes... active XO is a filter... and it seems that many people who work with EQ feel that 'active' is less intrusive than a 'mechanical' parts approach. I read one person, a while back, who works with the Behringer, who feels that getting out of their analog circuit and reconfiguring it to operate in the digital domain made a huge difference in having the Behringer disappear. However, it was too complicated for me, so I dropped the idea of using the Behringer for EQ'ing my present drivers. Perhaps I should re-think that.

With Warmest Regards ~ Richard

[planet10]

Have you had a chance to hear it in an OB application, Dave?

Not in an OB ... all the OBs we have done so far have the same characteristic sonic flaw. I do have at least 1 more OB project (deep) in the queue, and A10PeN is the leading candidate for mid-tweeter.

dave

[-Richard-]

Hi Dave ~

Your post begs the question: What is the "characteristic sonic flaw"?

Thanks in advance for any feedback you can share with us.

I will contact you soon.

With Warmest Regards ~ Richard

[planet10]

Your post begs the question: What is the "characteristic sonic flaw"?

I would guess it is the time delayed stuff off the back of the OB ... even outside with little or no reflection it is audible.

dave

[guest42212]

I would guess it is the time delayed stuff off the back of the OB ... even outside with little or no reflection it is audible.

dave

One mans best attribute is another mans flaw

[-Richard-]

Hi Dave ~

The 'time delay' I think you are referring to is an attribute that I find sets the OB paradigm apart from almost every 'box' speaker I have heard. My knowledge of horn speakers is unfortunately limited. Although I love the ideas they implement, helping to make the 'Single Driver' design approach a viable alternative to multi-driver speakers.

In my listening space, the attribute of the 'time delay'... the back wave of the drivers bouncing off of a wall behind the speaker and joining the front wave a few fractions of a second behind its 'throw', seems to create a holistic 'open' presentation that permeates the air/space with a very realistic (or the illusion of a realistic) sense of singers and or instruments floating in space.

This effect may very well be room dependent to work to advantage. A room with highly absorptive surfaces may work against this effect. My listing space leans a little bit more to the 'alive' response which may be sympathetic to the 'time delay' effect.

A designer friend once explained to me that that is how tubes work as well... the tube has a built-in 'time delay' that allows the signal to echo slightly, and it may well be that effect that helps to create the 'rounded' perception that many people find to be closer to the sound of 'live' music, or more 'wholistic' sounding than the apparent 'flatter' presentation of solid state amplification.

When you said, "even outside with little or no reflection it is audible"... do you mean outside in the open air with no walls to reflect against? That would be fascinating if that is what you meant... that somehow the back wave is able to be heard even though there is no surface to bounce off of. Since I respect the high level at which you stay involved with DIY audio, I take your observations quite seriously.

It would be interesting to visit your studio some day to hear what you consider to be a well-implemented audio design. In fact it is always interesting to visit peoples sound-rooms to hear what they hear.

Thanks for sharing with us Dave.

With Warmest Regards ~ Richard

[planet10]

... the back wave of the drivers bouncing off of a wall behind the speaker and joining the front wave a few fractions of a second behind its 'throw', seems to create a holistic 'open' presentation that permeates the air/space with a very realistic (or the illusion of a realistic) sense of singers and or instruments floating in space.

I don't think that is it. I do not have the same issue with bipoles which do the same (althou phase is 180 degrees different, and usually a more uniform match to the front radiation)

dave

[JohnR]

Just wondering if you measured the FR of the OBs that you tried? It's not hard to produce a nice null in the midrange if baffle shape and driver location aren't done carefully.

[planet10]

Just wondering if you measured the FR of the OBs that you tried? It's not hard to produce a nice null in the midrange if baffle shape and driver location aren't done carefully.

No. A null can be produced by moving the mic too.

This observation is across a number of quite different OBs. Lest problem (sonically) with the BIG baffle (16' wide)

dave

[MJK]

Your assumption is just not true my friend. You imply that any type of tank circuit robs a driver of presence and prevents it from bringing music to life. No driver is linear both on and off axis and the best speakers in the world make use of some type of correction, separate from limiting frequencies. I can pretty much assure you that I can measure and correct a driver which you would prefer in a blind test over the same unaltered driver at the same relative loudness. People often mistake loudness for presence and are opposed to any component that lies in the signal path. Of course they subsequently complain about things like driver shout and off axis linearity. Speaker design is based on establishing priorities, considering your environment and in many cases, compromise.  There is no free lunch.

I agree completely. When I am designing a speaker I will use anything that will improve the sound, filters are a standard and poweful tool. Adding a passive filter can help or hurt the performance, but with a properly sized and applied filter I have found the sound of a speaker is always improved compared to the purist approach of not accepting the added circuitry between the amp and the driver. I have yet to hear any of my speaker designs that have sounded better naked without filters then with just the right amount of passive adjustment. Making the right adjustments blind without measurement or analysis is not much better then just throwing a driver in any old box or on any old baffle and hoping it works well, sometimes you get lucky but not very often.

[matevana]

Hi Matevana ~

Your suggestion that: "People often mistake loudness for presence", is indescipherable to me. I have no idea what you mean by "presence" used in the context you describe here, relating it to loudness.

I am not certain I can adequately describe 'presence' as I used it in my post. For me it is an effect that goes beyond any one quality that can be named or accounted for in 'measurable' terms. It is a sense of 'aliveness'... or perhaps the illusion of "aliveness" and "there-ness" that allows the mind to feel that the music has a spontaneous life to it... that it is not merely being mechanically reproduced.

With Warmest Regards ~ Richard

In audio, the word "presence" generally refers to mid frequencies which affect how voices and instruments appear "present" in the mix.  Passive components used in-line to shape a drivers response will often reduce a driver's efficiency as part of the energy conversion. It is this reduction in efficiency that people can mistake for a less forward presence or a less lively sound.

You talk about this being an effect that goes beyond any one quality that can be named or accounted for in "measurable" terms. This sounds a bit like snake oil. There are very few driver characteristics that cannot be "measured" in some shape or form. So perhaps I'm not understanding your point.

[-Richard-]

All this sounds very erudite and has the illusion of 'certainty' about it. We are trained to think that we can be certain of everything we have an interest to 'know'... that everything can and should be known. We need only apply ourselves to measuring this and that, creating workable formulas that address the criteria that we think solves the problem and there we are.

We are trained to be problem solvers. And so we live inside of problems where we feel safe and secure in what we think we know. If someone suggests a paradigm that is 'outside' of what we think we know, it agitates us and we find ourselves defending what we know as a 'position'... we locate ourselves even deeper in what we think we know as a certainty.

If we love the sound of 'live' music that is not electrically amplified (spaces can be designed to 'amplify' sound) and we are interested in re-creating a recorded 'musical event' in our homes using electronic devices, there are several design approaches that have gained traction through commercial application.

The truth is that if we wish to design our own speakers, we are stuck with 'off-the-shelf' drivers, at least for the most part, that we do not create ourselves for the purpose we have in mind, and so must 'make the best of it' by modifying these drivers in some way to sound their best in our particular application.

We think that we want our drivers to not exaggerate any particular frequency gamuts and so modify them with circuits, or use digital EQ devices that bring the all-over frequency to be level. However, the sound of 'live' un-amplified music is an entirely different thing. The problem with reproducing music to sound as 'live' as possible is that our current technology is limited. So we try to get around that by discovering which application gets us a little closer to the sound of live.

On the way to doing this, all sorts of ideas enter into our considerations that bend our wish to create a close reflection of 'live', and quite often a perfectionist need to 'control' takes over our search.

I have never heard a speaker that reproduces every kind of music effectively. Most speakers favor different kinds of music, and even different kinds of voices and ranges of voices. If we design speakers and assemble components ourselves, we should be able to get closer to reproducing the music we love to listen to.

Deborah and I happen to love classical music. We attend live performances whenever it is available to us, either in Ojai or Santa Barbara. We are fortunate to have a marvelous music school in Santa Barbara, the Music Academy of the West, that holds master-class workshops once a year during the summer that is open to the public. Young musicians from all over the world are invited to attend these classes and for a few weeks, Deborah and I go from one master-class to another listening to these extraordinary musicians play their instruments or sing, and learn from master teachers, who demonstrate on their own instruments. We have attended these classes for many years and it imprints on the mind, as much as is possible, what live classical music sounds like in spaces that are not designed to necessarily amplify sound, such as a concert hall.

I also built a fully-keyed clavichord from a kit when I was in my late twenties and learned to tune it myself. That also imprinted a sense of what 'live' sounds like when strings are struck by brass tangents and begin to vibrate, creating lush and complex overtones (although this can only be heard in complete silence... the night is the magical realm of the clavichord). I currently play (not particularly well) a classical guitar.

So, my suggestion that the sense of 'live', that can sometimes be experienced with reproduced music by one's audio system, is not measurable, seems simple enough to me.

One can put together components and apply measurable formulas but the music may not have that ineffable sense of being 'live'. Now I think it might be helpful to suggest that if the music one listens to is already the result of electronic amplification, like electric guitar, then that is quite different, I think, then trying to reproduce un-amplified classical instruments.

In case you think I am some form of musical snob, nothing can be further from the truth. Deborah and I love musical forms that span the musical universe. I love Muddy Waters, or Willy Nelson or Johnny Cash or Miles Davis, and Deborah loves Billy Holiday and Cassandra Wilson and Keith Jarrett (just to mention 2 out of hundreds of great American musical geniuses) But we do listen to classical music, mostly favoring the voice, for most of our listening enjoyment. So that is what I am aiming for in my audio system.

That sense of sounding 'alive'... the sense of the music sounding 'live' in one's audio system... is most usually an accident. It is not the result of measurements. There are thousands of speakers (and their supporting gear) out there that do not sound 'live', although they may sound generically 'correct', and they are the result of carefully applied measurements. I am not trying to tweek the noses of the highly skilled speaker designers in our community. I have learned a great deal from all of you and I am deeply appreciative of your generous help and sharing of your insights as you discover things along the way of your own research. I am only sharing my 'personal' experience.

With Warmest Regards ~ Richard