Subwoofers - Final Thoughts with Martin Logan ESL 13A

@cundare2   : elodyne not only was measured in real time once but several times and in the other side and due that I listened at least 2 different Magico speaker  models I trust in what Magico says.

 

But, your last answer to me is ok, no problem at all. Merry Christmas.

 

R.

Dear @cundare2   : Thank's to post about the Perlisten and yes the manufacturer took care in its design and build quality level and according that design this subwoofer is a good unit.

 

However and always exist those " but " because in audio nothing is perfect.

 

The review and real time measurements that Audiolics made it showed that the reviewer never listened the Velodyne HGS 15 or 18 or even the 12 models where all those came with treated paper/pulp woofer material ( superior woofer material that any today one in that specific woofer designs. ) and not only that but he never measured the ( even today Velodyne DD models ) subwoofers with so low THD as the Velodyne units: 0.5% at below 20hz that's outperformed only by the 60K+ Magico unit ( o.4% ) that by " coincidence " uses treated paper for the woofers.

R.

@big_greg   Never mind. I posted my point. If I'm wrong p'lease just ignore it, why to worry about.

 

R.

@big_greg    You did not but you supported the post by @coltrane1  :

 

" 

I have never understood the preoccupation with bass. For half a century we didn’t even have subs. When you listen to a live band do you experience the bass is missing? I just don’t get it. I have ML’s, and I have more bass than I need. This without a sub. End rant. "

 

You made the point precisely.

 

R.

I forgot:

 

https://www.thebottomend.co.uk/ken_kreisel_int.php

Dear @big_greg    " For half a century we didn’t even have subs. When you listen to a live band do you experience the bass is missing? #"

and you posted this in your answer to that post:

 

"" You made the point precisely.  "

Well, he as you have a wide miunderstood about and are away fo at least a " mile ":

 

"

In one of my Ask Paul video questions, I was asked how far back subwoofers go in 2-channel audio. The community member had only become aware of subs as they related to home theater.

Of course, many readers of Paul's Post know subs date back much further than home theater.

From Wikipedia: In September 1964, Raymon Dones received the first patent for a subwoofer specifically designed to augment the low-frequency range of modern stereo systems (US patent 3150739). Able to reproduce distortion-free low frequencies down to 15 Hz, a specific objective of Dones's invention was to provide portable sound enclosures capable of high fidelity reproduction of low-frequency sound waves without giving an audible indication of the direction from which they emanated. Dones's loudspeaker was marketed in the US under the trade name "The Octavium" from the early 1960s to the mid-1970s. The Octavium was utilized by several recording artists of that era, most notably the Grateful Dead.

Two years later, in 1966, my former partner in Genesis Technologies and the co-founder of Infinity, Arnie Nudell, along with his airline pilot friend, Carry Christie, launched the second and perhaps most important subwoofer of its time, the Infinity Servo woofer, based on an 18" Cerwin Vega driver.

My experience with a subwoofer began a few years later when I was first introduced to a true high-end audio system. There, in the living room of local audiophile Norm Little, was serial numbers 1 and 2 of aerospace engineer Eugene J. "Gene" Czerwinski's creation, a pair of 18" Cerwin-Vega subwoofers capable of producing 130 dB at 30 Hz, an astonishing level during its time (or any time).

I suppose I have never gotten over the experience of hearing for the first time, all there is in the recordings, including subsonics.

Until you hear it all, you're not going to know what true high-end is.  "

 

"""" The first home subwoofer was developed during the 1960s by Ken Kreisel, the former president of the Miller & Kreisel Sound Corporation in Los Angeles. When Kreisel's business partner, Jonas Miller, who owned a high-end audio store in Los Angeles, told Kreisel that some purchasers of the store's high-end electrostatic speakers had complained about a lack of bass response in the electrostatics, Kreisel designed a powered woofer that would reproduce only those frequencies that were too low for the electrostatic speakers to convey. Infinity's full range electrostatic speaker system that was developed during the 1960s also used a woofer to cover the lower frequency range that its electrostatic arrays did not handle adequately.

The first use of a subwoofer in a recording session was in 1973 for mixing the Steely Dan album Pretzel Logic when recording engineer Roger Nichols arranged for Kreisel to bring a prototype of his subwoofer to Village Recorders. Further design modifications were made by Kreisel over the next ten years, and in the 1970s and 1980s by engineer John P. D'Arcy; record producer Daniel Levitin served as a consultant and "golden ears" for the design of the crossover network (used to partition the frequency spectrum so that the subwoofer would not attempt to reproduce frequencies too high for its effective range, and so that the main speakers would not need to handle frequencies too low for their effective range).

Subwoofers received a great deal of publicity in 1974 with the movie Earthquake which was released in Sensurround. Initially installed in 17 U.S. theaters, the Sensurround system used large subwoofers which were driven by racks of 500 watt amplifiers which were triggered by control tones printed on one of the audio tracks on the film. Four of the subwoofers were positioned in front of the audience under (or behind) the film screen and two more were placed together at the rear of the audience on a platform. Powerful noise energy in the range of 5 Hz to 40 Hz was generated at the level of 110-120 dB(SPL). The new low frequency entertainment method helped the film become a box office success. More Sensurround systems were assembled and installed. By 1976 there were almost 300 Sensurround systems leapfrogging through select theaters. Other films to use the effect include the WW II naval battle epic Midway in 1976 and Rollercoaster in 1977.

With the advent of the compact cassette and consumer digital audio formats, the reproduction of deep, loud bass was no longer limited by the ability of a phonograph record stylus to track a groove. It became possible to add more low frequency content to recordings. Home subwoofers grew in popularity, as they were easy to add to existing multimedia speaker setups and they were easy to position or hide.  """"

 

I'm almost sure that both of you never heard about Hartley subs.

 

tw, multiple subwoofers in an home system is only for HT in a two only stereo audio home system and for one seat position no one in any room needs more than two true self powered subs integrated to the room/main speakers through a high pass filter crossover..

 

R.

Dear firends all of you: We have to remdember that MUSIC belongs to the bass range and as better our room/system bass management as better the whole quality levels of the Room/system reproduction.

 

Other issue is that MUSIC starts ( rithm, dynamic power, natural color, natural agresiveness and brihtness, etc, etc,, nuances, ) with a fast TRANSIENT RESPONSE where the first " beat "in any instrument is the one that will makes a " rigth " harmonics development in all frequency ranges.

 

So name of the MUSIC is TR and only subwoofers can do it in the bass low range.

 

R.

@navyachts : " And would they be on the inside or the outside on the FL/FR speakers? "

 

With all respect that is a question you don’t need to make due that even if the other gentleman could has the same ML model as you the ROOM and probably the whole system chain linksand his preferences are different ( even the wife, if any. ).

 

Today subs come with a true advanced DSP electronic/software tool to integrates subs to almost any speaker room/system.

Look, my Velodyne models ( old ones. ) has no those tools and I took 1+ year to achieve where I’am today. I tested/try: behind the speakers, at side of the speakers, back between speakers, front between speakers.

My room is an inverted L shape so one of the speakers has not a near side wall. Finally the Velodyne’s are seated exactly near and in front of each speaker and subs are side firing ( the 15" woofers. ) in between , clearly not an orthodox positions

 

Btw, phase at 180º .

 

R.

 

@audphile1   : " No speaker is perfect. " 

You are rigth and not onlyabout speakers but no one audio home system item is perfect due that always it has trade-offs and is our personal choice which trade offs we take /took.

 

R.

@audphile1  : Wilson Wamm Master Subsonic goes from 10hz to 100hz using class A amplifier and Wilson has on sale active croosovers.-

 

What do you think of this vintage Krell:

 

Krell Master Reference Subwoofer Subwoofers user reviews : 4.5 out of 5 - 4 reviews - audioreview.com

 

R.

@ricred1  : Yes¡ ¡ ¡, certainly not you are wrong about: Velodyne is only a name as is REL or Sonus Faber or other names just names.

Maybe I have an advatage over you and this is that I always am willing to learn from any one including new comers/roockies. Eacc single day is a learning one for me.

 

I'm a MUSIC lover not a hardware lover but we need that hardware to listen MUSIC.

 

R.

Dear @audphile1  :  I could think that owning the Wilson Sabrina you already know from where came the today design or which are its roots. Any way this is the history:

 

first that D. Wilson designed his first speaker he was working by several years as recording engineering for different labels ( I own 3-4 different LPs recorded by D.Wilson that when I bougth it I was almost ignorant not only who was D. Wilson but many other audio main subjects. ).

The DW decided to design and manufacture a proffesional small monitor lovely speaker that was named Watt and that was used for many LP recording studios and latter on by audiophiles and had so success with the Watt that when all the people were asking for that Watt speaker but with more extended bass range and DW designed the Puppie ( bass unit ) that had great success too till the Watt Puppie VI. The Sabrina came from there in today version, so very fine " pedigree ".

No problem if you can't be aware of the IMD in the Sabrina even that it's down there and this is not the matters of this post but here the J.Atkinson real time measurements that confirms what I'm saying due its around 350hz woofer crossover frequency. E ven that a truly fine speaker:

 

" Wilson Audio Specialties Sabrina loudspeaker Measurements | Stereophile.com

 

In the other side, yes I'm enjoying my " old " whole system that when I bougth the ADS L2030 Proffesional Monitor speakers I was totally ignorant what  I bougth but this really special ADS speakers , as your Sabrina, has its own history.

 

Things are that in those old times ( early 80's ) Telarc Recording LP label ask to ADS to design and build a dedicated monitor according Telarc needs and it comes not the L2030's but a customer design with main speaker and subwoofer that were paired by Threshold big class A amplifiers designed by today N.Pass.

Telarc was happy but they ask for more and ADS introduce to Telarc in the customer design L2030 and the L1530 and theese Proffesional Monitors were the ones used in around 70 pressed Telarc different scores.

I born and live in México city and at the USA border in Laredo,TX an audio big store saler offered me the ADS L2030 that was only in exibition but only in passive way so I never heard and I bougth it because impressed me with out its big grille and bougth it: only subjectivity and ignorant of the L2030.

 

Well this ADS speaker is a true full range one with -5db at 16hz to 30khz. Its driver units are unique even for today top standards:

with two  14" PAPER pulp woofers ( as the today Evolution subs. Paper pulp has the best quality performance material that it's not outperformed by today other materialsssssss reproducing bass range: period. ) wired in parallel in different and closed " house " ( the overall speaker design is not only sealed one but each driver acoustic suspension design.).

Been a Professional Monitor the L2030 was designed with two midrange options: Line source and Point source along the single Tweeter. In Line Source mode the speakers runs the midrange through four midrange silk domes where 3 are the auxiliar drivers and one a very special main midrange that comes with bigger magnet and along the silk dome special Tweeter whe in Point Source mode runs only the main midrange with the tweeter where both driver are not coaxil but extremely close in between.

The main midrange silk dome and the silk dome tweeter where made expressily for ADS in Germany and both drivers are unique. The 1" silk dome has 24K Gauss as its motor ¡ ¡ ¡  The linearity true linearity of these two drivers is just exeptional and almost free of distortions.

My L2030 are up graded by me in this way:

 

"" These L 2030 was designed by Mike Kelly ( Aerial speakers ) and till today it match all my priorities.

It is " heavy " tweaked to do that: first it has " three hands " ( internally ) of a insulation/antivibrational treatment ( like a white paint. I can't remember the ingredients. ) from Acoustical Magic Company ( it works marvelous ) inside all the box ( a big one box: 58-5/8" ( H ) x 27-1/4" (W) x 13-1/8" (D) ).

It is internally hard wired with Silver Oval by Analysis Plus cable and KCAG by Kimber Kable. 

I take out the crossover ( now is external ) and change all the parts: resistors ( Powertron by Vishay. ), all silver air core solid ribbon ( 5.5 cms. of pure silver. Almost 2kg. of silver in the bigest one. ) Alpha-Core inductors , WIMA FKP 1 and KEMET caps  in the crossover, the speakers cables goes soldered directly to the crossover parts. This speaker crossover is tri-hard-wired from the  amps output to the 3-way crossover parts and speaker drivers. 

In reality are three separate/stand alone crossovers: one for the tweeter, one for the midrange and the other for the woofer, all these hard-wired directly to the amps ( no connectors. )

I'm only not biamp my system ( with the subs. ) but these ADS main/satellite speakers are true tri-wired in hard-wire directly from the amps to each crossover parts in the three way speaker design all the way down to the amplifier output.

I change the internal damping glass fiber by 10kg ( each one ) of long hair 100% virgin wool and change the fabric cloth of the grille for a " transparent one ".

Both speakers have at the rear-center the Antiresonant Vibration System by MICROSCAN model TM-8 that works from 20hz to 1.5Khz.

These L 2030 have: One acoustic suspension 1" silk dome tweeter, one main acoustic suspension 2" silk dome midrange, three auxiliar acoustic suspension 2" silk dome midranges ( similar to the main midrange but with a less powerful magnet. ) and two long-excursion acoustic suspension ( sealed. ) paper 14" woofers.

These are exceptional drivers especially the tweeter/main midrange ones.

These L2030 midrange design permit to " run " the speakers on " point source " mode ( tweeter and main midrange ) or through a " weighted " line source mode ( tweeter plus the 4 midranges. ), in this last " fashion " is how I have it ( hard-wired too. ). Its efficiency is 95dbs.  """

 

The main speakers are paired with a very old true Reference M:Levinson 20.6 monobloks designed by legendary J.Curl and these amps are up graded too and between other things and due that the pure class A are coupled my capacitor I changed that input capacitor for a way lower capacitanse Wima FKP1 cap ( better that even the copper Teflon Vcaps ( I tested and the Wima outperformed the over 300 dollars Vcaps for only 10 Wima dollars and it's with this cap change that the high pass filter for the L2030 happens so no additional stage for the high pass crossover. The signal comes directly from the phonolinepreamp and the signal to my Velodyne subwoofers comes directly too from that same phonolinepreamp and I'm croosing the subs/main at around 80hz, just a beauty. My Velodyne subs are not the latest model but are the last Velodyne where the woofer drivers are builded with paper pulp material similar to the L2030 woofers and to the Evolution today subwoofers. Go figure ¡ ¡ if I'm enjoying my room system. where I'm nearer to the recording that never before ( only two self powered subs. ).

Due that the 3-way L2030 drivers are wired all in parallel the amps looks around 1.7ohms impedance and the monobloks 20.6 puts  around 500 watts pure class A , nothing alter these monobloks at any SPL as nothing alter the L2030 response at any SPL. In some of my personal test proccess and with some tracks inside that test proccess I make some test with 97db SPL at seat position ( near field position ) with peaks at over a little 106db and I listened to that so high SPL only by a few minutes due that's only a performance quality test.

R.

Dear @ricred1  " " I don't want to be rude, but I simply own REL subwoofers. I don't work for them, I'm not a REL fanboy(I don't like their subs with a passive radiator), and I don't get into measurements.  ""

NO, you are not, you don't have to worry about. This is a dialogue.

 

" I don't get into measurements. " Well, I posted in this thread that always it's essential that every audiophile you included need to mantain a good equilibrium between our subjectivity and the objectivity ( specs, measurements, technical issues and the like ) and I can see that you have not that kind of equilibrium and go " walking " through 100% subjectivity as: " I like it " or that's the way I like it. Nothing wrong with that becaus that's you and that you use your room/system as HTS too and that's what REL site says and what REL makes always but REL is not truly competitive against say this today Velodyne that by specs and measurements puts on shame any REL subwoofer:

 

Digital Drive Plus - Velodyne Acoustics

 

There is no contest down there and only the 60K+ per unit  Magico subs are near the Velodyne with a 0.4% THD or the fantastic subwoofer coming by Evolution Acoustics that goes -3db at 7hz-100hz and -6d at 3hz to 100hz.

 

That Evolution subs unit comes with 4 treated PAPER  15" woofers and each sub weogths around 300kg and very expensive as are the Wilson subwoofers too. ( why treated paper instead other today materials?, please read my next post).

Those are two examples why objectivity is so important even that you don't care about and that is up to you and I respect that.

 

R.

Dear @ricred1 : In this link and in any REL information you can’t find out which is the 31/32 THD that is essentially a meaning of the true quality subwoofer performance levels. If you have information about then please share with us:

 

No.32-One-Sheet-August-17-Vfinal.pdf

 

In the REL manual we can read the main target of REL subwoofers:

" A REL is designed to augment the performance of " full range " speaker systems in order to provide linear response below 15 hz. "

There is no information which kind of " linear " response below 15 hz ¡ ¡ ¡ ? ? ? when it says in the specs that is down 15 hz with a -6db deviation. That has no sense.

That " augment " means that the " full range " speakers " continue to play " full range " with high MD and now you have two bass sources playing together from 90hz and belows it ¡ ¡ ¡ ¡ ¡ Terrible for say the least and then you pay over 10K for one Rel unit.

 

I respect all your opinions but as mine is only an opinion that IMHO is full of misunderstood in this particular subject and REL specifically.

 

Btw @tablejockey " swarm ( 4 or more subs in the room ) function as the Harman link posted in this thread shows only to even the low bass response all over the room ( if you have only one seat position and cares only about your seat position you don’t need more than 2 subs as confirmed the Harman link. ) and it does not look for bass quality response and/or the quality response of the main speakers and its woofers developed IMD: swarm just does not helps about. Get it? and yes I can be wrong but this is my whole take rigth now .

 

Thismis the link:

Microsoft Word - whitepaper10.doc

 

R.

 

Dear  @audphile1   : Overall agree with you however there is one issue where almost does not matters the room/system you own and this is the IMD developed by speaker woofers if the speaker passive internal crossover is high as in the ML or your Sabrina. Wilson is no exception to that IMD.

 

Now:  " Turn up the bass level knob in the back of the ML woofer cabinets. "

 

If @navyachts  makes that then the IMD will goes higher and higher, IMHO it's not the " solution ". There is no way to lower that ML woofers IMD.

 

R.

Dear @navyachts  :  The SVS App will be tell you all about the placement of 2 subs and everything around:

 

SVS App Specs:

• The most powerful and flexible Bluetooth controlled subwoofer DSP app, works with both iOS and Android operating systems.
• Easiest and most convenient way to adjust crossover frequencies, parametric EQ, polarity, room gain and all other bass management functions.
• Three convenient custom presets allow for perfect tuning in any room or system, from your favorite seat.

• Single tap adjustment for controlling variable port tuning with standard, extended and sealed modes.
• Unique bidirectional feedback shows adjustments in real time on both app and subwoofer interface.
• Easy-to-follow tutorial provides clear guidance for all functions

You need a High-Pass filter for your main ML speakers, this is critical.

 

Yes the 4000 can function for your room/system

 

R.

 

R.

@navyachts : Pleaso do it you a favor and stay away of REL that it’s not a true sealed subwoofer but with a passive radiator that almost function as a ported one.

 

In this link you can read about and the reference by REL on Home Theater use.

 

Here this could be your game:

 

SB16-Ultra Subwoofer | SVS

 

Btw this is not true about the ML subs on not faster enough:  " and that they are not fast enough for my speakers "

 

SoundStage! Max dB - Fast Bass, Slow Bass - Myth vs. Fact (06/1999)

 

R.

 

Dear @audphile1  :  I like your Wilson speakers and the Boulder electronic that I already listened.

 

Even that your Sabrina is  IMHO better than the ML the subwoofer issue is the same as is the same the trouble with the Sabrina developed IMD and you can't change it in the way you posted.

 

Look from the same expert ( not an audiophile as us ) that I posted his explanation:

 

" 

TYPES OF "MAIN" SPEAKERS

In addition to all the above, there is the complex issue of the "main" speaker you are coupling to. There are essentially 6 types of speakers that exist:

1) sealed
2) port in the front
3) port in the bottom
4) port in the back
5) a dipole, which is a flat panel such as an electrostatic (Sound Lab, Magnepan, Quad, Beveridge, Martin Logan, etc.)
6) an true omnidirectional system such as the MBL or the BEOLAB 5.

Each of these speaker types couples somewhat differently to the room, and certainly to a sub in that room, and therein lie the problems in acceptable integration.

A port is ALWAYS nothing more than a cheap way to attempt to get free bass out of an enclosure and /or driver that's too small. It's a holdover from the 1930's when because of driver inefficiencies (especially when compared to today's units) you had to do everything possible to increase the useable output over the desired range of low frequencies.

At one level, all the guyz want 9 foot speakers in the living room (read "man-cave"). All spouses, of whatever gender, want tiny 3" speaker cubes that disappear, but expect 9-foot results from them. Since they haven't repealed ohms law or any other laws of physics while we were sleeping, the only way to get correct sound is to move a correct amount of air.

Lets examine ported speakers. We'll start with the worst case, the port in the front. At mid bass frequencies, say 50-80 Hz, the LF driver moves IN the cabinet, the air in the cabinet is elastic, and the port air moves out of the cabinet. Because of the frequency at which the cone is moving, by the time the cone moves out (forward) again, the port air is now moving out, so in front of the cabinet the two air pressure sources sum together and you get a fake bass "bump" or "boost".

As you go lower and lower in frequency, at some low frequency the air pressure from the LF driver and the air pressure from the port are exactly opposite each other, so they cancel, and there is no more audio at that frequency: it disappears.

When the manufacturer of a speaker cabinet defines the frequency response (i.e., 37 Hz - 20kHz +/- 3dB) this is what is defined by the entire arrangement of the port and the air in the cabinet and the driver. At some low frequency the port air is exactly out of phase with the driver air pressure and since they cancel, there is NO output from the cabinet into the room. Therefore with a ported cabinet, the entire sloppy concept is this juggling game between the response of the drivers under air pressure, the passive crossover inside the box, the port size and placement.

You must understand that ANY driver goes down to 0 Hz, or DC. If you put a battery across a speaker, the cone moves out and stays there. If you were to have a DC coupled power amp feeding a speaker - ANY speaker, from a 1" dome tweeter to an 18" rock n roll stage bass driver - and you put 4 Hz into it, it would simply move back and forth at 4 Hz. Of course in order to actually "hear" the audio it would have to be in the generally accepted passband of 20-20,000 Hz and the cone diameter would have to be enough to actually move some air in the room. So it is the overall combination of the driver size, the excursion, the box size, (therefore the air back pressure) and many other factors that determines the overall response of that "speaker" AS AN ENTITY.

That means IF you were to simply put those same frequencies through the mains and the sub (that means with no crossover, and this is the mistake that nearly everyone makes) you would now have 3 sources of LF energy and differing phase: the 'main' LF driver, the port, and the sub, all fighting with each other in the time domain. A further corollary is that since the air inside the [mains] cabinet is elastic, the phase relationship of the port air to the driver air is also a sliding one; that means it's "out of phase" — and smearing — over a wider range of frequencies than you might think.

If the port is on the back, again, a cheap attempt to use the back wave bouncing off a wall to give 'additional' bass, you have the ADDITIONAL issue of the transit time it takes for the back port pressure (already delayed because of the elasticity) to leave the cabinet, travel back, hit a wall, and bounce back around the front of the cabinet again; therefore this LF wave MIGHT be "in phase" with the front driver BUT BE 360 OR EVEN 720 DEGREES LATE; therefore it sounds like the bass frequencies are ok in the frequency domain but the IMPULSE RESPONSE is now muddied.

Also, in the case of back ported or (type 5) dipole speakers, since the path length from the back of the speaker to the wall and bouncing back around to the front of the speaker is a fixed physical entity, at some frequencies you are adding and at some frequencies you are canceling: you have simply made a physical/mechanical frequency comb filter that you can't do anything about. Sound Lab's answer to this (for use with their flat panel electrostatic speakers, which are dipoles) is they sell you a "Sallie", which is an absorber to absorb the entire back wave output of the electrostatic panel. Since now there is no comb filtering; all you are therefore hearing is the front signal.

PORTED SUBS

A ported sub for home use is even more wrong than ported mains. Now you would be attempting to acoustically add together in the room at least SIX low frequency sources with differing phase and frequency slope conditions: the LF drivers in your two mains, their ports, the sub driver, and its port. In addition, since it's a bandpass it cannot go down low enough for serious Home Theater effects. (that typically means a real 20Hz or close to it.)

In some cases such as a bandpass sub used in a club or on a modest-sized stage in your local pub, you are most concerned with efficiency and not with getting frequency response "flat" down to 20 Hz; therefore a correctly set up bandpass box that might roll off at 35 to 45 Hz is quite sufficient and also very efficient for the defined purpose. And again, as a point of reference, "flat" response in the frequency domain is FAR AND AWAY the LEAST important phenomena: impulse response in the time domain is the most important, but it cannot be measured with a handheld meter therefore almost everyone simply ignores it. If you're interested in learning about the newest (and evolving) pro sound system / stage methods of "steering" bass, Dave Rat has some very cool videos here:

part 1  www.youtube.com/watch?v=VwLH7zP6Lwo

part 2  www.youtube.com/watch?v=B-3pURYOwfw

part 3  www.youtube.com/watch?v=aSZK9Altvm8

There's a nice article here:
www.prosoundweb.com/channels/study_hall/tech-topic-friends-in-low-places

But back to our Home / HI-FI / 2-channel / Audiophile / Surround Sound systems: There is ONLY ONE truly correct way to "add a sub" to a system in an controlled listening room situation: you must correctly cross over the 2 sealed cabinets; and their timing must be correct. ANY other method will lessen the focus and clarity and imaging you have tried so hard to preserve.

I have many clients and customers with extremely exotic high-end 2-channel systems that are all chasing the holy grail of 3D holographic sound imaging, and until they follow my distinct guidelines they are never completely satisfied with the results.  "

 

Audiophiles as us and MUSIC lovers as us need to have as a fact it's a MUST to have or  develop an EQUILIBRIUM between OBJECTIVITY and SUBJECTIVITY

in all our room/systems decisions to achieve the best overall quality MUSIC level performance that puts us nearer to the recording and NO it's not other " road " to achieve that target but all these is each to each one of us and not what I said.

 

Please read this link and even the whole thread:

 

https://forum.audiogon.com/discussions/do-you-think-you-need-a-subwoofer/post?postid=310058#310058

 

R.

Dear @ozzy  : I respect your opinions.

 

" Running the main speaker’s full range and augmenting the lowest frequencies with the sub(s) is the best of both worlds. "

 

Unfortunatelly it does not exist those " both worlds " and probably you don't understood what I posted about that very high ML crossover 300hz frequency that procuce a very high Intermodulation Distortion that contaminates all the ML quality response.

What that ML is doing is to develops " trash "allover the MLspeakers through that severe IMD.

When that " trash " is out of that ML woofers then the midrange, midbass and high frequency ranges now arepristine, with clear sound, nearer to the original signal and shiny all that system as never before:NO MATTERS WHAT.

 

@navyachts  deserves the best from his room/system.Btw, Velodyne is not the only subs that can help you inside your budget.Only look for a sealed subwoofer design.

 

R.

Dear @navyachts :Main subjectUissue why add subwoofers in an stereo room system is not really " add more/deeper bass ".

All speakers including yours and the lovely S7 owned by @orthomead or the great Rockport owned by  @workeuptobose normally are designed using a internal passive CROSSOVER from a 2-way speakers to 4-way and up speakers.

Where is the " problem " there about that crossover frequencies for the different speaker drivers frequency range?:

In your case your ML crossovetr frequency to the woofer is 300hz and the speaker can goes down to around 22hz and; what that means?

it means that at the same time that that woofer drive must handle the 22hz, 30hz or 4o hz it must has too reproduce frequencies that can go over 300hz and the big woofer excursion need it to develop 22hz makes that the frequencies over 100hz develops a high INTERMODULATION DISTORTIONS ( no matters what. ) and this IMD is a huge signal reproduced degradation and it’s precisely here where 2 self powered subwoofers ( NOT ONE. ) helps a lot because when the woofer of the ML main speaker handled frequencies above 80hz-90hz and is liberated from the bass below 80hz-90hz that IMD goes automaticallt down and not only the bass range will shines but the midrange and hi frequency range too because we have to remember that MUSIC harmonics are developed by all the speaker drivers and if the IMD already gone down in the bass the bass range harmonics will be CLEAN with lower distortions and will permits that the mid range and hi frequency ranges stay in the same way: lower in distortions and clean/purity with lower signal degradation.

The " side " benefits of adding those subwoofers are not only what I posted but now the low bass range it will be reproduced by a dedicated driver designed in specific to handled with absolut applomb the frequency range and go deeper too in that range and with a dedicated amplifier that was designed to run on that bass specific range too along that your main amplifier will be a lot les distressed when is not playing/looking the low bass frequency range.

All those means that we need a high-pass filter to separates the frequency that goes through the subwoofers and the frequency that goes through the main speakers.

The solution that way is: win to win.

You said you need to improve the quality performance ( including bass. ) to one seat position and this means you need ONLY 2 self powered subwoofers crossed at 80hz, you don’t need the swarm solution that is for several seat positions.

Other issue with subwoofers is that exist quality levels between different manufacturers designs and due that the foundation and where the MUSIC belongs is the bass range you need subwoofers with very low developed distortion levels .

 

@ozzy posted to you: " play the main speakers full range " and with all respect this is a mistake that almost all audiophiles made/make by recomendation as REL manufacturer. Here you can read by an expert in the subject why that assuption is wrong even if we own the Magico S7 ( I can’t find any where the crossover frequencies of the S7 but obviously use a crossover and develops too IMD as the Rockport too that additional is a ported design and this means that here we have 3 bass sources: the front woofers, the back port and the subwoofers ( no one can control timing to run in our ears bass range because those 3 bass range coming with different delay) ):

 

"

The ONLY correct way to add a sub to system is to define everything ABOVE the sub’s [frequency] range as an entity; clearly define the impulse, phase, and lastly frequency response of this entity; and then make a new "2-way" system where the sub is one way and everything above it is the ’other’ way. The parts must be combined correctly so that there are no cancellations and no smearing of time-related musical events.

This CANNOT be easily measured in the frequency domain, because you could have (as an example) an 80 Hz signal coming from both the mains and the sub, and if the sub is 12.5 msec late the two sources will "seem" to be in phase but the sub really will be 360 degrees, or one full wavelength late. It is the impulse smearing that this affects, but people don’t measure that because there is no simple "hand held" phase or impulse meter as there is an SPL meter.

The REASON this meter does not and essentially cannot exist is that in order to measure impulse response or phase response you need a starting REFERENCE point, (in time) and in a speaker system, since the signal has to travel through circuitry, amplifiers, passive crossovers inside the speaker box and then hit the driver; therefore the first reference point MUST be acoustic.

There ARE computer based impulse response systems such as the TEF, ( very quick technical blurb HERE; full story HERE ) but they are involved, require real instrumentation, are expensive, have a seriously steep learning curve, and they are absolutely not the kind of thing most ’consumers’ -- or audiophles, can be bothered with or have patience for.

So the overall view of adding a sub is this: In essence you are designing and assembling a new speaker system which is "2-way": the sub is one way and everything "else" above it in frequency is the 2nd way.

Simply connecting a sub to existing mains speaker (or amp) terminals ( or self powered subs. ) is the WORST POSSIBLE WAY to do this. EVERYTHING scientific and acoustic about this method is wrong, from the additive delay issues to the back EMF of the mains affecting the LF signal. However there are plenty of people who simply do not understand correctly integrated bass, and they will be reasonably happy simply sticking another box on to their system without regard to timing, phase and frequency issues, and they will think it sounds "ok" or "good" and for those people it doesn’t really matter.

Indeed the only thing that does matter is an individual’s happiness with their system, whether I or anyone else thinks it’s right or wrong.

But I want you to know and understand the truth, so to get purely technical...."

 

Btw, the subwoofer with lower THD ( Total Harmonic Distortion ) level and reasonable price are these by Veñodyne esclusively design due that too comes with high pass filter:

 

Digital Drive Plus - Velodyne Acoustics

 

Regards and enjoy the MUSIC NOT DISTORTIONS,

R.