[-Richard-]

I go back and forth between Roger Modjeski's new 245.1/45 SET tube amp and Vinnie's
Signature 30 amp with my Open Baffle speakers... it keeps things fresh for me ~

In order to hear substantial bass from my B200 extended range drivers in my present OB
configuration I have been adding a pair of monitor speakers that help to fill in the bottom end.

I spoke to Vinnie a few days ago and he suggested I use a Step Correction circuit with the B200
drivers... it shelves down the mid to high range... flattening out the rising frequency curve of the
B200's... it makes the speakers less efficient but when volume is applied to them the all-over
sound is perceived with very substantial bass because the entire frequency lifts at the same time ~

I applied the SC circuit using Roger's 45 amp and there was noticeably more bass... just as Vinnie
said there would be... but the all-over sound seemed just a tad out of focus... I knew instinctively
with a flash of insight that the Signature 30 amp would sound fantastic with this new circuit in place...
I switched amps and fired up the Signature 30 and... WOW!!!!!!!!!

THIS IS NOT AT ALL SUBTLE... THE SIGNATURE 30 SOUNDS TRULY FANTASTIC!!!!!!!

Deb and I were immediately captivated by the sound and dropped everything we were doing...
Deb brewed some green tea and we sat down to listen to an assortment of our favorite CD's...
everything from female jazz voice with small ensemble backup to classical music sounds so
incredibly rich, dynamic, detailed and 3-Dimensionally present!!!!!!!!

The bass frequency response filled out to subwoofer dimensions!!!

I should also add that I am using a new Dac that is rather fabulous... with the right ancillary
equipment of course... the Citypulse Stereo D/A Converter DA7.2X... with its robust gain,
penchant for pulling out detail and ripe bass, together with the Signature 30 and the OB's,
the effect is truly beguiling... intimate, deeply textured, harmonically rich, intensely present...
with spatial cues that create a believable 3-Dimensional sense of reality ~

I am incredibly excited... Deb's response is exactly like mine... deep musical pleasure!!!!

This new SC circuit, the Signature 30, my OB's and the new Dac are creating exquisite magic
in my house ~

Thanks Vinnie... for your friendship, advice, insights and creative genius... you have really created
a masterpiece!!!!! May the audio gods forever smile on you... forever favor you with their
grace and benedictions ~

Warm Regards ~ Richard ~

[GHM]

Richard I'm glad to read you have discovered the BSC circuit isn't a bad thing. I know people like to keep it simple around here. But as you have discovered some extra components in the path can make a positive difference. Your descriptions mimic what I, JLM, Paul Bui, Bemopti123 discovered some time ago with the F200a drivers and the BSC. There's no way I would listen without it in the chain now.

All the best and good listening

[-Richard-]

Hi GHM ~

The particular eccentricities of the SC/BSC circuit seems to draw on the little 4 watt 45 amp in
a way that renders it drier and less liquid than it usually sounds... it could be a subtle clipping
that is creating a kind of contraction in the sound... on the other hand the Signature 30 has been
released to blossom in a remarkable way... somehow the synergy with this new circuit favors the
Signature 30's ability to render harmonic and spatial magic ~

This is not a subtle difference but substantially of a much higher order of resolution than I have
heard before... the Signature 30 has gone from the most beautifully sounding SS amp I have ever
heard to something quite different... even richer, much more intimate, digging much deeper into
the fabric of the music to render something ineffable... something so much like live music that
Deb and I are thrilled... it is like discovering an entirely new amp... yet again!!!

Perhaps, GHM, the new circuit has illuminated and fleshed out the bass of the B200 in such a way
that the Signature 30 can now show me what it is really capable of doing... there is something
totally new in its power to resolve the musical space... the inner dimension of the music!!!!

Of course you are right!!!! With this circuit no subwoofer need apply... now Deb wants me to sell
the cabinet speakers that I was using before the CS/BSC circuit!!!!

Always nice to read your thoughts, GHM!!!

Warm Regards ~ Richard ~

[GHM]

Hi Richard..what has happened is now you have a more balanced sound. No longer is the SD imbalanced towards the midrange or highs. The bass was always there. It was just masked by the protruding midrange. I think the 4 wpc amplifer may have lost the edge because the efficiency dropped a little. Just a guess...I'm also thinking the reason the RM or any other low wattage tube amplifier works so well with the SDs, is because of its character to help give the SD more of a perceived balanced sound. With a BSC in the chain..this certain character isn't needed. If you had a higher current tube amplifier ..everything would reappear that you love about tubes.

Now you're really ruined as the combo of SD and BSC will show you the weakness or imbalance of many speakers and equipment geared towards HiFi..even the recordings done this way.

I've always enjoyed reading your post, as you have a terrific way with words.

ATB

[Canyoneagle]

In order to hear substantial bass from my B200 extended range drivers in my present OB
configuration I have been adding a pair of monitor speakers that help to fill in the bottom end.

I spoke to Vinnie a few days ago and he suggested I use a Step Correction circuit with the B200
drivers... it shelves down the mid to high range... flattening out the rising frequency curve of the
B200's... it makes the speakers less efficient but when volume is applied to them the all-over
sound is perceived with very substantial bass because the entire frequency lifts at the same time ~

Hi Richard.
So, am I understanding correctly that the step circuit allows you to eliminate the monitors and allow the OB's to stand alone?
Thanks,
Michael

[-Richard-]

Hi Richard.
So, am I understanding correctly that the step circuit allows you to eliminate the monitors and allow the OB's to stand alone?
Thanks,
Michael

Hi Canyoneagle/Michael ~

There is no question about it... the B200's with the Step Correction circuit now has the characteristics
of a full-range driver... the bass is there to create the all important "ground" of the music... there is
no sense of anything missing... the gestalt of every musical form I listen to feels fully fleshed out ~

It is important to qualify that somewhat by saying that in most of the music Deb and I listen to
the suggestion and a bit of the visceral "presence" of the bass is all that we need to create the illusion
that the bass is ripe... any emphasis on the bass beyond that sounds artificial to us ~

I can explain this better by giving an analogy... Sam Tellig once remarked that a full orchestra
playing symphonies is not an appropriate scale of music for home reproduction... he suggested that no
home audio system could be made to reproduce the sweeping dynamic range and sheer volume that
would simulate what you would hear in the concert hall... I feel that insight could be extended to
any musical form that has powerful driving bass lines as well... I realize that many reading this might
think I suffer from an overly sensitive response to what for them would constitute the thrill
and exhilaration they derive from music that pulsates its powerful rhythms as part of the music's
expressive "language" ~

But it is important for me to feel that the music "fits" my home space in a way that makes sense...
powerful driving bass lines beyond a certain sonic level would easily saturate our living space
and overpower our senses... the result would be a fatiguing and a numbing of the senses ~

I have never attended a rock concert for that reason ~

The pleasure we now derive from RWA's Signature 30 amp and the B200's in OB using the
Step Correction circuit cannot be overly emphasized... all the thrills are there!!!!!!!
and the bass sounds powerfully present... enough to satisfy our sense of what the music needs
to come fully alive!!!!

GHM's take on what is going on sounds quite right to me... his wealth of experience and careful
listening habits shows in his insights ~

But the Signature 30 amplifier sounds so rich harmonically, so refined, it captures the fleeting
inner intelligence of the music with such uncanny precision, that I now feel that nothing is
missing that an SET amplifier would add to the dimension of the music... everything is there!!!!

Warm Regards ~ Richard ~

[Vinnie R.]

Hi Richard,

I had a very good feeling that you'd love the BSC circuit with your B200 baffles. 

Here is a thread about it over on the Open Baffle Circle (I have added some comments as well): http://www.audiocircle.com/index.php?topic=31582.0
Scorpion made some posts about it on the Darkstar thread and I figured it was worth a shot, especially because the parts were not much $$$ and this was so quick and easy to do.

The 30-watts really comes in handy because you do lose some efficiency, but man is it so worth it! 

Thanks for your post!


Hi GHM,

I know people like to keep it simple around here. But as you have discovered some extra components in the path can make a positive difference. Your descriptions mimic what I, JLM, Paul Bui, Bemopti123 discovered some time ago with the F200a drivers and the BSC. There's no way I would listen without it in the chain now.

I am in the same boat and cannot go back to listening w/o the BSC circuit.... it just makes everything sound so well balanced.  I'll steal Richard's words to describe it:

intimate, deeply textured, harmonically rich, intensely present...
with spatial cues that create a believable 3-Dimensional sense of reality ~

Yeah, that's how I'm hearing it and LOVING it! 

I'm also thinking the reason the RM or any other low wattage tube amplifier works so well with the SDs, is because of its character to help give the SD more of a perceived balanced sound. With a BSC in the chain..this certain character isn't needed. If you had a higher current tube amplifier ..everything would reappear that you love about tubes.

I think GHM nailed it here... at least this is how I found it to be when using an Almarro A205 SEP (5 watts?).  When running the baffles without the BSC circuit, I found the Almarro to color the sound (expecially with "looser" and less controlled bass, darker mids and highs) in such a way that I think helped give a more fleshed-out bottom end.  After the BSC circuit was installed, I couldn't stand listening to the Almarro for more than a couple of songs... the balance was totally lost and it sounded much too colored, slower, less engaging, etc.  The lack of power also wasn't good when I wanted to turn up the volume.  This brings me to another point... with the BSC circuit the sound is really, really nice at louder levels.  It is such a pleasure to listen to! 

As for the efficiency with the BSC, I can only take a guess that it is in the 90 to 93dB range.  The Signature 30 drives them with total ease, and the Signature 70 Monoblocks do an even better job! 

Thanks for posting, guys!

Vinnie

[Canyoneagle]

Richard,
It sounds to me like you and your wife share similar perspectives on audio (as well as other things, it would appear...).  Like you, we do not feel the need to be overwhelmed by bass - we are more interested in the musical experience.
I have recently acquired a slightly used pair of compact hemptones, (which I plan to drive with a sig 30), and words cannot convey what I feel when I sit and listen to them.  Many would characterize these as "bass shy", but they convey enough of the visceral impact (that you describe) for my preferences.

I find your experiences with your OB's and the sig 30 VEEEERRRRRY intriguing, and would love to learn more about what you have done (in a more appropriate venue, to avoid going off topic).

So, more fuel for Vinnie's already brightly burning fire, please........
It seems that Vinnie has a real gift (as does Louis) and is doing his heart's work here.

Warmly,
Michael

[miklorsmith]

Tangent -

I have a pair of the new 70's ordered that I will be able to compare with my Yamamoto A-08s.  My speakers are Def. Pro's, so the power difference won't be a factor.  Or will it?  I have a feeling that it will, despite what the "numbers" would indicate.

Adam at Zu really likes 200 wpc tube amps on his Def's.  Overkill?  Maybe not?  If the Signature amps can really keep the magic of SETs with power and control, a whole new world of magic opens to lovers of speakers under 100 db efficient (pretty much everybody).

Based on the early returns, it seems we are all in for a treat.  What a time to be listening!

[bprice2]

Just curious...would a BSC circuit added to a 4.5", Fostex, single driver speaker perform as described above with the B200 OB configuration?  I assume this addition is only applicable to the B200 and/or OB speakers in general, but had to ask anyway.

Thanks,

Brett

[-Richard-]

Hi bprice2 ~

Vinnie was able to recommend the use of the Step Correction circuit because he is currently
using them on his own B200 Open Baffle speakers... Vinnie experimented with several variations of
this circuit before he felt certain that it was the optimal implementation of that circuit given the
functional operating parameters of the B200 drivers ~

Your question should be put directly to the person who designed your closed baffles... once a driver
is placed into a box an entirely different set of operating parameters are brought into play...
as compared to a driver that is operating in an Open Baffle implementation ~

Most closed baffles are designed to extend or modify at least some of the frequencies of a driver...
usually the bass, for example, is pushed down by the ingenious (hopefully) use of ports ~

I hope this helps a little ~

Warm Regards ~ Richard ~

[ashok]

Just curious...would a BSC circuit added to a 4.5", Fostex, single driver speaker perform as described above with the B200 OB configuration?  I assume this addition is only applicable to the B200 and/or OB speakers in general, but had to ask anyway.

I use a BSC circuit in my Omega TS-1 bass reflex speakers, which use the Fostex 207E 8" drivers. The function of the circuit is the same - tame the rising frequency response of the driver beyond the baffle step frequency. The width of the baffle plays a part in the circuit component values. You can take a look at the following: http://www.quarter-wave.com/General/BSC_Sizing.pdf for an excellent description of the problem. I also used Martin King's Excel spreadsheet to come up with the component values for the BSC circuit for my Omegas. Works very well.

Regards,

Ashok

[bprice2]

Your question should be put directly to the person who designed your closed baffles...

Thanks, Richard.  Sounds like sage advice to me.  BTW, I enjoy reading your posts.  I believe we share some of the same equipment in common...Signature 30 and Omega Super 3 Bipoles, if I remember correctly.  I will ask Louis about his thoughts on implementing a BSC circuit.

You can take a look at the following: http://www.quarter-wave.com/General/BSC_Sizing.pdf for an excellent description of the problem.

Thanks, Ashok.  I appreciate the paper.  It helped me understand some of what Richard was saying.

[Bwanagreg]

Richard,

I'm accomplishing the same thing in the digital domain on my PC music server using EQ. I works like a charm, doesn't it? The B200s (mine are homebuilt aperiodics) don't seem to mind the extra bass energy they are being fed a all. In fact they thrive when driven hard. I'm going to have to go the RWA 70 route to get even more headroom, I can tell. I'm still using my first generation Bolder Tripath battery wonderbox.

[JLM]

I tried the BSC (baffle step circuit) in my Bob Brines FTA-2000 speakers (same as GHM, Paul Bui, Bemopti 123, and others) with a 12 wpc tube amp and it over compensated the bass.  Tubes of course are known for their poor damping characteristics and the resulting exagerated, uncontrolled (flabby) bass.  Sans BSC, the tube amp provided relatively flat, but loose bass resopnse.

Now with 40 wpc of chip amp power the BSC is indispensable, even though it only adds about 3 dB to the bass output in my estimation.  Keep in mind that the raw driver used, the mighty Fostex F200A, is rated down 10 dB at 30 Hz in free air to start with.

In an open baffle, more compensation of course would be needed.  The B200, or any smaller driver I'm aware of, would need even more compensation.  I would expect this to drop overall efficiency down to near where the FTA-2000 is and within a couple of dB of the F200A in open baffle.  Hard to find a free lunch when you knock heads with the laws of physics.

As my BSC is raw (off the shelf parts thrown together and left naked) I first thought about building a nice box, playing with boutique parts, and wiring it directly to the driver (to eliminate a connection).  But in my attempts to over think (and avoid work), the idea of using a  Berhinger DEQ 2496 (between transport and DAC), came to mind.  But alais, I'm a poor audiophile and need to secure "research funding" in order to complete room treatments, provide a pre-amp, and mod my CDP to accept the DEQ before I can proceed.