Ultimate Low Frequency Extension

RBFC · Aug 5, 2016

Mark Seaton's newer offerings, the F18+ and the F18, are 18" single subwoofers that are meant to be stacked or "swarmed" in multiple units. These subs come either as 4000W powered "master" units ( the +), or as unpowered "slave" units that can draw power from a master unit. Seaton also custom-makes the connecting cables to your specified length (last price for cabling I saw was $100 for a 20 ft cable!). Therefore, one could inexpensively experiment with various placement/configuration options for several of these subs. The slave unit idea will allow placement where one does not have a 20A circuit located. This has certainly peaked my interest for upgrade path....

Lee

astrotoy · Aug 5, 2016

I've had subs in my system for many years. Currently it's a Velodyne DD18, even though I have Avantgarde Duos which go pretty deep. When I heard the Magico Q5's with a complete Constellation amp/preamp setup, they were wonderful, but I missed the deep bass of my system. My best reference are live symphony concerts with organ (the first movement of the Saint-Saens organ symphony has some 16Hz pedals that you feel in a big hall, deeper than in the more spectacular last movement - I was fortunate to hear Charles Munch conducting it back in the '60's with Berj Zamkochian playing the organ with the BSO in Symphony Hall in Boston (the same forces as the great RCA recording from 1961). Also hearing the great Berlioz Te Deum in London with Colin Davis conducting the LSO, the deep whacks on the bass drum made my body shudder. In my home system, I worry that something will come loose and tumble down. Having lived through the Loma Prieta earthquake in 1989, I can tell you what really low frequency waves feel like!

Larry

Ron Resnick · Aug 6, 2016

LL21 said:
I think one area where (i will hazard a guess) standalone subs could use some more work is in the quality/transparency of their crossover network. I think on the adjustability/variability, we have a few subs which have become quite sophisticated. I know Velodyne's standalone SMS-1 has been around for some time, and it is essentially built into their reference subs. I like the adjustability...but i am NOT so convinced about the quality of the crossover network as relates to the main speakers.

. . .

I think tbh, more people (incl me) would use the crossover in subs like the Velodyne to crossover the main speakers if we were convinced it was that good.

+1

If a company's whose electronics I currently use made an active cross-over then I would trust it.

LL21 · Aug 6, 2016

Ron Resnick said:
+1

If a company's whose electronics I currently use made an active cross-over then I would trust it.

You could buy an outboard active crossover you like, use it to dial-down the main speakers & deliver low end signal to the subwoofer and THEN use the subwoofer's own customization to further finetune. Or for example, you could simply by JL Audio subs with their new outboard crossover.

microstrip · Aug 6, 2016

LL21 said:
You could buy an outboard active crossover you like, use it to dial-down the main speakers & deliver low end signal to the subwoofer and THEN use the subwoofer's own customization to further finetune. Or for example, you could simply by JL Audio subs with their new outboard crossover.

It will depend on what you are prepared to accept in the path of your signal. Even the CR-1 uses JFET-input audio-grade op-amps. Some people would not sleep well knowing the signal coming from their tubes is going through such devices!

In the 90's Audio Research manufactured the EC22 http://www.arcdb.ws/EC22/EC22.html - an active crossover using discrete FETs circuits, using the same devices and a similar topology of their SS preamplifiers, such as the SP15. At less their users would not feel disturbed by the presence of ICs!

Ron Resnick · Aug 6, 2016

LL21 said:
You could buy an outboard active crossover you like, use it to dial-down the main speakers & deliver low end signal to the subwoofer and THEN use the subwoofer's own customization to further finetune. Or for example, you could simply by JL Audio subs with their new outboard crossover.

For me to trust it it would have to be made by Aesthetix or Gryphon or VTL or Lamm, etc.

LL21 · Aug 6, 2016

Ron Resnick said:
For me to trust it it would have to be made by Aesthetix or Gryphon or VTL or Lamm, etc.

OK...like any preference for electronics. I can see that. Personally, from what i am told, the current Wilson crossover is quite good as well, and if it was designed by DW for his XLFs, i have to imagine the last thing he would want is for his own equipment with his name on it to compromise the transparency of his reference speakers. I would also blindly trust the Arrakis active crossover since it was designed by Andy Payor as an inextricable part of his longstanding (and nothing-short-of-amazing) reference speaker.

Ron Resnick · Aug 6, 2016

LL21 said:
OK...like any preference for electronics. I can see that. Personally, from what i am told, the current Wilson crossover is quite good as well, and if it was designed by DW for his XLFs, i have to imagine the last thing he would want is for his own equipment with his name on it to compromise the transparency of his reference speakers. I would also blindly trust the Arrakis active crossover since it was designed by Andy Payor as an inextricable part of his longstanding (and nothing-short-of-amazing) reference speaker.

About the Wilson Audio Watch Controller and about the Rockport Technologies Arrakis cross-over I think that is a completely reasonable assumption -- but we don't know, because these guys do not specialize in electronics.

LL21 · Aug 6, 2016

Ron Resnick said:
About the Wilson Audio Watch Controller and about the Rockport Technologies Arrakis cross-over I think that is a completely reasonable assumption -- but we don't know, because these guys do not specialize in electronics.

No, though I admit with Andy Payor designing one of the great TTs of all time, and [apparently] doing a lot of design and manufacturing work on his own speakers in-house, i would categorically trust his design aptitude...particularly when one of the MOST critical parts (ie setup/calibration to a particular speaker) has already been done as part of the design.

Regarding Wilson, i take your point here as i have again been told the original Wilson Controller from many, many years ago was too expensive and not particularly good. No longer the case today...but i can imagine that a SOTA active crossover could well best it even in a Wilson setup. What i DONT know is whether even within flexible active crossover networks, whether it helps to KNOW what speaker you are designing the active crossover for. Are there variables most crossovers do not quite allow one to customize fully which then are best matched with certain speakers? no clue.

Ron Resnick · Aug 6, 2016

LL21 said:
. . . What i DONT know is whether even within flexible active crossover networks, whether it helps to KNOW what speaker you are designing the active crossover for. Are there variables most crossovers do not quite allow one to customize fully which then are best matched with certain speakers? no clue.

This is an excellent question. Knowing the speaker and parameters in advance must help -- if for no other reason than to avoid unnecessary flexibility and components and circuits in the crossover.

GaryProtein · Aug 6, 2016

Digital crossovers have tremendous flexibility and will allow you to create almost any target curve you can scribble on a graph, but they obviously involve the use of ADC and DAC's.

On the analog side, the Pass Labs XVR1 allows a great degree of flexibility in crossover points and slopes. On the Pass, unused poles of the crossover are not in the circuit, keeping noise and distortion to an absolute minimum.

Ron Resnick · Aug 6, 2016

GaryProtein said:
. . .
On the analog side, the Pass Labs XVR1 allows a great degree of flexibility in crossover points and slopes. On the Pass, unused poles of the crossover are not in the circuit, keeping noise and distortion to an absolute minimum.

Gary, Have you read the operating manual for the XVR1? The first tip literally is: Peace of Mind Required

Settings can be changed only with the unit off and by plugging in shorting jumpers to select a few out of hundreds of possible settings. To me it is user-(very)unfriendly.

LL21 · Aug 6, 2016

Ron Resnick said:
Gary, Have you read the operating manual for the XVR1? The first tip literally is: Peace of Mind Required

Settings can be changed only with the unit off and by plugging in shorting jumpers to select a few out of thousands of possible settings. To me it is user-(very)unfriendly.

Oh my word...i cannot imagine how that works for anyone who is not a serious expert. Someone who can calibrate a system [almost] without listening to it by knowing the measurements and the math. otherwise, it can become a serious exercise in frustration where one powers down the system...changes something...powers it back up, etc.

Good, bad or indifferent, the Velodyne allows me to make changes to a test tone while the measurement is live, and also while i am listening to music which allows me to test for certain drums/beats i [think] i know well in real time and listen to the adjustments as i am making them.

LL21 · Aug 6, 2016

Coming back to my question (whether an external crossover designed by a speaker designer has any inherent advantage in blending with that particular designers speakers due to some unique internal speaker design elements), here is an off-shoot of the original question:

are there are any super-specific design features/measurements/design elements of a main speaker's bass (phase, delay, resistance, [insert proper technical terms here]) where (even with an INFINITELY adjustable crossover) one must still actually KNOW EXACTLY all of those precise measurements/features of all of those various elements in order to be able to truly adjust the crossover to get an external sub to match the main speaker's bass in an ideal way?

FrantzM · Aug 6, 2016

LL21

There ways and they are rather well known. Amir, for one, has written some excellent articles on the matter. I am too lazy to point you toward these

The fact of the matter is that it is not that difficult to mate subs with mains. One has to be willing to learn, to understand, measure and experiment. One has to reconcile oneself with digital which reigns supreme down low. One must measure then adjust to ear and to taste.

One interesting way to learn how to mate your mains with subs:
Get REW: A free tool of incredible power, install it on your laptop.
Get a calibrated microphone such as the umik USB circa $100
get a decent tripod <$50
Read on how to use REW to measure your bass... Free but leaning curve can be steep.
Read, measure, read, read,measure ...
Try to put your hands on a pair of cheap subs, leave the Velodyne in the system, of course
Read, measure, read , measure.. Ask questions on this forum and others
Read, measure ...

The results may shock you even with the Velodyne plus cheap subs...

microstrip · Aug 6, 2016

Ron Resnick said:
Gary, Have you read the operating manual for the XVR1? The first tip literally is: Peace of Mind Required

Settings can be changed only with the unit off and by plugging in shorting jumpers to select a few out of thousands of possible settings. To me it is user-(very)unfriendly.

It is the price to pay to have fine tuning and only selected discrete elements in the section handling the signal - the JL Audio uses multiplication DACs to carry this function.

microstrip · Aug 6, 2016

LL21 said:
Coming back to my question (whether an external crossover designed by a speaker designer has any inherent advantage in blending with that particular designers speakers due to some unique internal speaker design elements), here is an off-shoot of the original question:

are there are any super-specific design features/measurements/design elements of a main speaker's bass (phase, delay, resistance, [insert proper technical terms here]) where (even with an INFINITELY adjustable crossover) one must still actually KNOW EXACTLY all of those precise measurements/features of all of those various elements in order to be able to truly adjust the crossover to get an external sub to match the main speaker's bass in an ideal way?

Lloyd,

IMHO no. And most of of those who will tell you yes, either have no proper work to show or have very different sound preferences from you.

Measurements can help setting a system, but are not an indicator of a "good match in an ideal way". And yes, I was using REW last night.

But I am prepared to learn from different opinions.

GaryProtein · Aug 6, 2016

Ron Resnick said:
Gary, Have you read the operating manual for the XVR1? The first tip literally is: Peace of Mind Required

Settings can be changed only with the unit off and by plugging in shorting jumpers to select a few out of thousands of possible settings. To me it is user-(very)unfriendly.

Yes I have. Cover to cover. If you do not read it thoroughly, you might as well leave the XVR1 in the three cartons it comes in. For those who are interested and dedicated, the effort has its rewards.

I loved Nelson's opening paragraph. Here it is:

PASS LABORATORIES XVR1 ELECTRONIC CROSSOVER NETWORK OWNERS MANUAL

Some audio products are designed for anybody who can put batteries in a flashlight. This product is not like that.

Some audio products are designed so that you don’t have to study the manual. This product is not like that, either.

Some audio products are designed so that you plug them in and you don’t have to fool around with them for a year before the system is greatly improved....

LL21 · Aug 6, 2016

Thanks, FrantzM and Micro. Good to know. The bass response using the microphone & test signal at the location where i listen is +/-3db from 15hz to 200hz and closer to +/- 1.5-2db from 20hz to 100hz, so on that simple line chart, it looks pretty good. I still hear minor anomalies on music from time to time, but its definitely far better than i've heard it (incl our old place where we were for nearly 10 years). I am sure there are loads of other measurements (off axis, delay, etc) but i am not sure i have the technical expertise to figure out how to delay or remove time delay, etc particularly given that the sub can really only go in 1 spot.

microstrip · Aug 6, 2016

LL21 said:
Thanks, FrantzM and Micro. Good to know. The bass response using the microphone & test signal at the location where i listen is +/-3db from 15hz to 200hz and closer to +/- 1.5-2db from 20hz to 100hz, so on that simple line chart, it looks pretty good. I still hear minor anomalies on music from time to time, but its definitely far better than i've heard it (incl our old place where we were for nearly 10 years). I am sure there are loads of other measurements (off axis, delay, etc) but i am not sure i have the technical expertise to figure out how to delay or remove time delay, etc particularly given that the sub can really only go in 1 spot.

We should remember that systems with self adjustment and optimization are becoming very good. As far as I understood in Marty system using the CR1 crossover and the new mk2 Gotham's with the new Digital Automatic Room Optimization (D.A.R.O.) system Marty is using the settings coming from the D.A.R.O. setting.

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