[Danny Richie]

Not that I don't doubt you, Dave,... but has this been confirmed by anyone here in this thread using "real" test measurement gear?  If so, can someone please direct me to the post?

FYI, the SPL meter that Gary laid on my leg was an $1,800 Breul & Kjaer meter model 2232.

[sfdoddsy]

Once again, this 'SPL statement is meaningless. Presumably you were listening to music, which has a range of frequencies. So the measurement was of the overall output of the speakers. No-one is doubting they can easily hit 105db or whatever somewhere. What some of us are doubting is whether they can hit 20Hz specifically at those levels. As you claimed.

[sfdoddsy]

Wow! What a discussion!
I have 3 12" OB GR subs on a side and I am pretty pleased with them. I had also tried out a number of other subs, but could not get them to integrate well with my Sound Labs. These are the best yet.
Are they perfect? No.
What would I like: More slam. As I understand it, the real low-bass impact in classical music actually comes from the 40-80Hz region (timpani, low piano notes, bass drum). Although my bass is clean, goes very low and has great texture, it still lacks the "startle factor" I have experienced in previous systems with x-mission lines (Hartley 24" in a huge home-made box).
Maybe: a. I am expecting too much; b. I was confusing distortion with slam; c. It's mostly a room problem; d. After much fiddling I still do not have the right setup. Maybe all or none of the above.
But, questions: a. Have the servo 12's reached their highest potential? b. Are you working on improvements to the drivers? c. Are you working on improvements to the amps? d. Would the bigger amps be better in my setup?
Don't get me wrong. You have a great product. This is all about my relentless pursuit of perfection.

Dipole bass pressurizes the room differently. This is part of what makes it sound so clean.

The trade-off is that you won't get the bass slam you get from say a typical sealed sub. Servo or otherwise.

[dBe]

deleted by Dave

[dBe]

Terra Sonde AudioToolBox: http://www.terrasonde.com/products/dat.php  Mine was an ATB Plus calibrated and the SPL measurements agreed with my B&K.  I still Have my ATB1



Dave

Here is an article about the original:  http://www.soundonsound.com/sos/feb00/articles/audiotoolbox.htm  I'm fortunate in that the one I have still works and is the quickest spot-check unit that I have ever had.  I sold the Plus because it was too quirky and they tried to pound too much into a small package.

An addition.  When someone says: "Not that I doubt you..., but........"  that means that they do doubt and just don't want to own it.  Kinda' circumspect in my book.

[lowtech]

Here is an article about the original:  http://www.soundonsound.com/sos/feb00/articles/audiotoolbox.htm  I'm fortunate in that the one I have still works and is the quickest spot-check unit that I have ever had.  I sold the Plus because it was too quirky and they tried to pound too much into a small package.

An addition.  When someone says: "Not that I doubt you..., but........"  that means that they do doubt and just don't want to own it.  Kinda' circumspect in my book.

Dave, Just trying to be polite and somewhat P.C. about it.   

The claim is suspect for a variety of reasons already mentioned in this highly informational thread.  And, as Steve points out, there is a big difference between measuring a 20Hz sine wave and music at 100+ db.  I'm looking for verification about the low-bass output capabilities that have been claimed by the designer.  Like I said, measuring this accurately seems pretty straight forward.  Perhaps Danny can step up and provide what I'm asking?  I think others' will find the results useful too - if nothing else, we can put this issue to rest.   

[THROWBACK]

SFDODDSY: "Dipole bass pressurizes the room differently. This is part of what makes it sound so clean.
The trade-off is that you won't get the bass slam you get from other types of bass."

I guess I don't get that. Seems to me that the impact from the fundamental of a timpani beat at 65Hz or a bass drum beat at 45Hz would have more to do with how the wave is launched from the speaker than with the room. Am I wrong? (Actually, I was wrong once in 1956 and the memory still haunts me...)

I suppose I could be getting some cancellation in the overlap between the subs and the ESLs if they are out of phase, but so far my measurements (Stereophile Disc 2 warble tones and Radio Shack meter) do not seem to show that.

[jtwrace]

I am using a prototype DAC from db Audio Labs. I have been in the beta testing group for its development for the past year. Big strides have been made. No wait, "huge" strides have been made...   

I did A/B compare an earlier version of it to the Light Harmonic DaVinci DAC. That is another really good DAC. I think at the time it was $12k or something. The latest version is now $20k. So a bit pricey, but at the top of the performance chain.

Well, I look forward to all the measurements on this dac.  I'll say that the ODAC which was designed soley on engineering and measurements is pretty amazing for the $150 retail cost.  One doesn't need to spend thousands of dollars to get excellent digital playback. 

BTW-what computer do you use for your tests?  Apple or Mac?

[cab]

BTW-what computer do you use for your tests?  Apple or Mac?

Is that a trick question?

[dBe]

Dave, Just trying to be polite and somewhat P.C. about it.   

The claim is suspect for a variety of reasons already mentioned in this highly informational thread.  And, as Steve points out, there is a big difference between measuring a 20Hz sine wave and music at 100+ db.  I'm looking for verification about the low-bass output capabilities that have been claimed by the designer.  Like I said, measuring this accurately seems pretty straight forward.  Perhaps Danny can step up and provide what I'm asking?  I think others' will find the results useful too - if nothing else, we can put this issue to rest.   

Politeness and political correctness will yield nothing but inane BS in a discussion such as this.  You are either calling a person a liar or you aren't.  The person is either telling the truth or they are not.  I consider the words I use very carefully. "The word "disingenuous" has been bandied about a lot in this thread and that just sucks.  To say: "Not that I don't doubt you, Dave,... but..." is the definition of that word.

sfdoddsy said this: "Once again, this 'SPL statement is meaningless. Presumably you were listening to music, which has a range of frequencies. So the measurement was of the overall output of the speakers. No-one is doubting they can easily hit 105db or whatever somewhere. What some of us are doubting is whether they can hit 20Hz specifically at those levels. As you claimed"

Seriously?  Do you think we are amateurs at this?  I was using a Peak/Hold RTA tool that captured all of the frequencies within a certain time window defined by the selections made of measurement parameters on the tool itself.  This was in 3 second intervals.  If you know the piece of music at all you would know that this is a valid time slice to get the true frequency dependent response consist for that particular piece of music.  The 18Hz tone lies at the bottom threshold of the DAC used at the time which employed no brick wall filters to distort the readings.  First, know what you are arguing and then don't make assumptions that others are novices at their craft.

What really, really concerns me about this thread is the attitude taken by the questioners.  I understand that it is PC to assume that people in business are nefarious, dastardly bastards that want nothing more than to separate their customers from their wallets.  We have it beaten into our heads by the Guv'mint every day.  Neither Danny or I qualify for the 1% at the top to get taxed to death.  We are just the guys trying to run businesses in the face of all of the Guv'mint regs that are killing us.  I am a man of faith and run my business accordingly.  That is why I have a 100%, no quibble money back guarantee on my products.  I have less tha a 1% return ratio on what I build.  Like wise, I have known Danny for many years and one of the reasons that he and I are great friends and business associates is that he not only shares my faith, but my business ethics.  Neither one of us will lie to a customer.  That is not the way to run a business and it is no way to answer to Someone Greater than us.  Once again, truth is truth and lies are lies.  Neither one of us will do that intentionally.  We may be wrong... we are human.  Thing is both of us will entertain the discussion of what makes great sound and how we can add to it.  We bust our butts day after day trying to put out GREAT sounding products at reasonable prices.  For the most part we have great businesses built by people that are satisfied customers and word of mouth.  Great small businesses are not built on lies.  That is the quickest way to bankruptcy that I know of.

Dave, back to the shop at 5:52PM MST

[AJinFLA]

I hope you don't mind, if I ask that could we for a while discuss about "Dipole basses for Maggies"..? ;=)

Well, there isn't exactly an overabundance of those. Danny's servo kit is one of the few options and sounds very good to boot. Will it fit your needs/room, etc, etc? Possibly so.

cheers,

AJ

[lowtech]

Politeness and political correctness will yield nothing but inane BS in a discussion such as this.  You are either calling a person a liar or you aren't.  The person is either telling the truth or they are not.  I consider the words I use very carefully. "The word "disingenuous" has been bandied about a lot in this thread and that just sucks.  To say: "Not that I don't doubt you, Dave,... but..." is the definition of that word.

sfdoddsy said this: "Once again, this 'SPL statement is meaningless. Presumably you were listening to music, which has a range of frequencies. So the measurement was of the overall output of the speakers. No-one is doubting they can easily hit 105db or whatever somewhere. What some of us are doubting is whether they can hit 20Hz specifically at those levels. As you claimed"

Seriously?  Do you think we are amateurs at this?  I was using a Peak/Hold RTA tool that captured all of the frequencies within a certain time window defined by the selections made of measurement parameters on the tool itself.  This was in 3 second intervals.  If you know the piece of music at all you would know that this is a valid time slice to get the true frequency dependent response consist for that particular piece of music.  The 18Hz tone lies at the bottom threshold of the DAC used at the time which employed no brick wall filters to distort the readings.  First, know what you are arguing and then don't make assumptions that others are novices at their craft.

<snip>

Dave, back to the shop at 5:52PM MST

Dave, I'm truly sorry you have taken such offense to my question and/or the way I asked for someone to substantiate the claim.  Up to now, I've read ZERO details about how you took your measurements.  I first I had thought you used an iPhone and then learned that you used a B&K meter.  Now, I learn that you did use music but used a peak-hold feature while some low-frequency information (music?) was occurring.  Perhaps if you had presented this information up front I would have phrased my question slightlly differently.  Music is music, and while you may think that you're measuring 18hZ or 20Hz or 30Hz or whatever, it's not very scientific.  I think you'll pobably agree?  There may have even been a few other vendors in the building doing the same thing at the same time?

Still, I'm looking to Danny or an idependent 3rd part to take some SPL measurements with some "reasonable" test gear to substatntiate the claims of 100+ db output at 20Hz.  I'm not sure why you seem so heavily invested in defending Danny - he's capable of taking these measurements and reporting back the results without a fuss (or at least he should be).  It may only take him 10 minutes of his time to accomplish this...   

[sfdoddsy]

What really, really concerns me about this thread is the attitude taken by the questioners. 

Dave, back to the shop at 5:52PM MST

The attitude of the questioners is due entirely to the way Danny in particular uses hyperbole and exaggeration to hype his own products, and denigrate those of everyone else.

We've actually been quite moderate, compared his characterisation of some his questioners as lacking the education to understand his products, others as 'flat-earthers', his earlier comments about DEQX etc etc etc.

As has been mentioned earlier, no-one is saying the OB servo subs are not very good products. But they do not blow everything else out of the water. They will not, barring an unprecedented repeal of the laws of physics, play at the levels Danny suggests down low unless the T/S parameters on his site are incorrect. And his claims about caps, cables, anti-vibration products and so forth are at the very least debatable.

When you present your products in the tone and manner of a snake oil salesman, people start to suspect that that is indeed what you are.

And they start to look at everything you say through that lens.

This has been pointed out several times in this thread, and it is shame you and his other business associates are unable to see it.

It may be unfair, but that is how it is.

[dBe]

Dave, I'm truly sorry you have taken such offense to my question and/or the way I asked for someone to substantiate the claim.  Up to now, I've read ZERO details about how you took your measurements.  I first I had thought you used an iPhone and then learned that you used a B&K meter.  Now, I learn that you did use music but used a peak-hold feature while some low-frequency information (music?) was occurring.  Perhaps if you had presented this information up front I would have phrased my question slightlly differently.  Music is music, and while you may think that you're measuring 18hZ or 20Hz or 30Hz or whatever, it's not very scientific.  I think you'll pobably agree?  There may have even been a few other vendors in the building doing the same thing at the same time?

Still, I'm looking to Danny or an idependent 3rd part to take some SPL measurements with some "reasonable" test gear to substatntiate the claims of 100+ db output at 20Hz.  I'm not sure why you seem so heavily invested in defending Danny - he's capable of taking these measurements and reporting back the results without a fuss (or at least he should be).  It may only take him 10 minutes of his time to accomplish this...   

Please read very carefully what I said:  I used a Terra Sonde AudioToolBox Plus to do the measurements.  I stated that it calibrated to (agreed with) my B&K.  I used the Real Time Analyzer function that reads in 1/6 octave increments with a high pass at 15Hz to a lowpass at 22KHz.  Rooms were separated by other rooms and it was a closed room system... hence the easy 100dB (+-ish) at 18Hz readings.  It would really help if you read all of the words and not just skim.

I assume that you understand what a RTA measurement tool does.  Perhaps that is my bad, but I made an assumption that since you were adamantly participating in this thread that you have a grasp of measurement methodology.  I still assume that this is correct.

FYI, I made several measurements in the room when we played the "Deeper" track.  The 100dB reading @ 18Hz was the low reading.  I measured over 106 in a room corner which is to be expected even with dipoles.  We started doing measurements because we found ourselves getting really, REALLY loud due to the low distortion that we had in the system.  It is way too easy to get dangerously loud with a low distortion system.

I'm beginning to agree with Brian.  Here we are beating our brains out in a thread trying to defend what we know, do, measure and make our livings at to people that want to pick nits.  I have a lot of orders to get out and here I am...  I need to apologize to my customers athat are waiting on me to get their units out and will do so pointing to this thread.  Perhaps THEY may wish to weigh in.

Dave

[dBe]

The attitude of the questioners is due entirely to the way Danny in particular uses hyperbole and exaggeration to hype his own products, and denigrate those of everyone else.

We've actually been quite moderate, compared his characterisation of some his questioners as lacking the education to understand his products, others as 'flat-earthers', his earlier comments about DEQX etc etc etc.

As has been mentioned earlier, no-one is saying the OB servo subs are not very good products. But they do not blow everything else out of the water. They will not, barring an unprecedented repeal of the laws of physics, play at the levels Danny suggests down low unless the T/S parameters on his site are incorrect. And his claims about caps, cables, anti-vibration products and so forth are at the very least debatable.

When you present your products in the tone and manner of a snake oil salesman, people start to suspect that that is indeed what you are.

And they start to look at everything you say through that lens.

This has been pointed out several times in this thread, and it is shame you and his other business associates are unable to see it.

It may be unfair, but that is how it is.

Whatever.

[sfdoddsy]

SFDODDSY: "Dipole bass pressurizes the room differently. This is part of what makes it sound so clean.
The trade-off is that you won't get the bass slam you get from other types of bass."

I guess I don't get that. Seems to me that the impact from the fundamental of a timpani beat at 65Hz or a bass drum beat at 45Hz would have more to do with how the wave is launched from the speaker than with the room. Am I wrong? (Actually, I was wrong once in 1956 and the memory still haunts me...)

I suppose I could be getting some cancellation in the overlap between the subs and the ESLs if they are out of phase, but so far my measurements (Stereophile Disc 2 warble tones and Radio Shack meter) do not seem to show that.

There is much discussion aout  this here:

http://www.audiocircle.com/index.php?topic=35304.0;nowap

The link to the Linkwitz paper is worthwhile.

[lowtech]

Please read very carefully what I said:  <snip>

Dave

Cool beans, Dave.  Perhaps you can reread my post?  It ended asking for a link to the detailed information that you have since provided.  You could have just responded with a link... without all the heated rhetoric.

Now we just need to understand how the laws of physics are being broken.   

Cheers!

[sfdoddsy]

Whatever.

Thank you for amplifying my point.

Two recent threads in the OB forum have gone off the rails recently. This one, and Studiotech's build thread (now cleaned up).

What, I wonder, do they have in common?

[dBe]

Cool beans, Dave.  Perhaps you can reread my post?  It ended asking for a link to the detailed information that you have since provided.  You could have just responded with a link to what you've since provided... without all the heated rhetoric.

For a Christian, you sure seem to have a short fuse.

Cheers!

Not really.  Where does it state that a Christian (you drew that assumption... I could be a Druid for all you know.)  has to take it in the shorts?  Grace in all things certainly, but tell the truth is paramount.  There is no short fuse here at all.  I was simply stating facts.  I suppose that "Christians" (if indeed that is what I am) need to be meek and apologetic for our view points.  BTW:  there are supposed to be no references or denigration of religion here.

You seem to confuse my position with anger.  I dn't get angry much anymore.  Totally counterproductive.  I do recognize denigration of position for what it is and will call it EVERY time I see it.  either gainst me, my acquaintances or others that I feel are getting raked for no particular reason than to satisfy ego.  Ego is over rated, too.  You either have a certain capability or you don't.  Doesn't mean that one has to get all jacked up about things that really don't matter in the overall context of life.  This discussion is what it is: dumb.  No one is going to concede their positions and there will be no winners.  There never are in discussion such as these.  All they do is piss some people off and others, like me, just wonder WTF all of this is about in the context of good audio.  Chest beating is great sport , but completely nonproductive.

Again, YMMV

Dave

[dBe]

Thank you for amplifying my point.

Two recent threads in the OB forum have gone off the rails recently. This one, and Studiotech's build thread (now cleaned up).

What, I wonder, do they have in common?

I don't care.  Sincerely.

But I question.  You, perhaps?