Choosing an amp for a subwoofer

my experience with both power cords and fuses on my sub towers speaks to how much nuance is part of subwoofer performance. and an amp that is not efficient but is asked to power a large bass driver in a sealed cabinet will likely stress your power grid to some degree and have trouble staying linear. so 'any well made power amplifier' will not necessarily perform optimally as a sub amp. obviously this is a subjective question. how good is 'good enough'?

what is your subwoofer/deep bass reference?

if you hear what a purpose designed class D amp can do when it is (1) purpose designed for it's job, and (2) used in a sub/bass unit that is fully designed to be fully integrated into the speaker system.........your expectations for a sub amp will change.

I am not sure how many crossovers include phase control (nor how many amps, for that matter). I suspect most if not all digital crossovers do, but far fewer analog crossovers. Phase control adds flexibility in subwoofer placement and allows tweaking to optimize room response. Without that your primary lever for optimum response is placement, but the need to phase-align sub(s) to mains at the crossover frequency means the optimal placement for smoothing room response and optimal placement to blend with the mains rarely matches...

Since the sub amp likely requires the most power, making it efficient is a reasonable goal. As Mike notes, reducing the average load on your power circuit is a good thing. Still have do deal with power peaks, natch. By offloading the sub band from the rest of the system, speakers and amps, overall sound typically improves.

I use one of the Crown XTi Series 2 amps for my subs. It has a very easy to use and powerful DSP built in and plenty of power, the only potential issue is fan noise. At low speed it's hard to hear but at high it's loud. If you have your amps in a separate equipment room than it will be no issue.

Rob

Mike Lavigne said:

my experience with both power cords and fuses on my sub towers speaks to how much nuance is part of subwoofer performance. and an amp that is not efficient but is asked to power a large bass driver in a sealed cabinet will likely stress your power grid to some degree and have trouble staying linear. so 'any well made power amplifier' will not necessarily perform optimally as a sub amp. obviously this is a subjective question. how good is 'good enough'?

what is your subwoofer/deep bass reference?

if you hear what a purpose designed class D amp can do when it is (1) purpose designed for it's job, and (2) used in a sub/bass unit that is fully designed to be fully integrated into the speaker system.........your expectations for a sub amp will change.

Click to expand...

Mike

I am willing to grant you that you hear the contribution of cable in a system .. up there in frequencies above 200 Hz... My position on cables has not changed, just for the sake of civil discussions, I will grant you that... I, however have the greatest doubt that fuses or power cods contribution is audible with a subwoofer. I also don't think that fuses contribution in the power supply is audible, that is an aside. but in the bass on subs? My skepticism is taking the consistency of granite.
Now as for built for the purpose subs ... I am of the opinion that in most rooms , with most speakers, the quality of bass reproduction is increased by the addition of subwoofers. Your speakers may not need subs at the listening position due to the fact that the mains go very lowe by their lone selves and indeed the towers are their subwoofers.. I don't think I would bother to add subs to the Genesis Dragon either ... I do however believe that aside from those speakers and similar designs , I will use subs and they don't have to be built for the specific speakers. Any good subs (as in any thing in life there are good and bad) with appropriate crossover (read with phase control, flexible slopes, types and cut off frequencies) correctly set up will do

I am not sure I understand what you mean by "stressing your power grid".Also my subwoofer bass reference ... The best bass I have heard was from an IB with a Pro amp 4 x 18 inch LMS drivers driven by Crown amps, ... The next ,the bass from the genesis 1.2, Another one which surprised by the quality was an IB driven by QSC amps with only 2 Blueprint 15 inch drivers, helped by an in-the-room Martin Logan Descent... I also very much like what I heard from the top Paradigm subs, the JL Audio Gotham and the Submersive, they all come with their own amplifiers not built for the purpose of one given speaker.

FrantzM said:

Mike

I am willing to grant you that you hear the contribution of cable in a system .. up there in frequencies above 200 Hz... My position on cables has not changed, just for the sake of civil discussions, I will grant you that... I, however have the greatest doubt that fuses or power cods contribution is audible with a subwoofer. I also don't think that fuses contribution in the power supply is audible, that is an aside. but in the bass on subs? My skepticism is taking the consistency of granite.

Click to expand...

Frantz, Frantz, Frantz.

why would an improvement to power supply performance (a fuse upgrade) be so hard to imagine to where skepticism is so strong? and why would a power cord change be relatively credible compared to the fuse? they are both working on the same problem.

I can tell you that both made small but easily heard improvements. not earth shaking, but valuable and appreciated.

btw, happy Sunday morning to you.

Now as for built for the purpose subs ... I am of the opinion that in most rooms , with most speakers, the quality of bass reproduction is increased by the addition of subwoofers. Your speakers may not need subs at the listening position due to the fact that the mains go very lowe by their lone selves and indeed the towers are their subwoofers.. I don't think I would bother to add subs to the Genesis Dragon either ... I do however believe that aside from those speakers and similar designs , I will use subs and they don't have to be built for the specific speakers. Any good subs (as in any thing in life there are good and bad) with appropriate crossover (read with phase control, flexible slopes, types and cut off frequencies) correctly set up will do

Click to expand...

i'm sure that somewhere there is a system with full range speakers which has added subwoofers that fully, completely, absolutely integrate. I've simply never heard one yet that does that. not that subwoofers cannot overall take you further, but to my ears there is always a price to pay at some point in coherence. so while I agree that most systems can benefit from added subwoofers, the result is not all positive. and an added full range crossover has it's own sonic limitations.

I am not sure I understand what you mean by "stressing your power grid".Also my subwoofer bass reference ... The best bass I have heard was from an IB with a Pro amp 4 x 18 inch LMS drivers driven by Crown amps, ... The next ,the bass from the genesis 1.2, Another one which surprised by the quality was an IB driven by QSC amps with only 2 Blueprint 15 inch drivers, helped by an in-the-room Martin Logan Descent... I also very much like what I heard from the top Paradigm subs, the JL Audio Gotham and the Submersive, they all come with their own amplifiers not built for the purpose of one given speaker.

Click to expand...

I was reacting to Gary's comment;

GaryProtein said:

For a subwoofer almost any well made high power amplifier will do the job well.

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I don't agree with that comment. I do agree that there are some good high power amps that are good subwoofer amps.

and as far as some amps stressing the power grid, that is not that uncommon.

in my system I have -4- Class D 1000 watt amplifiers on the bass towers, and then the two darTZeel 458's. that is 5000 watts to power potentially. with a 96db 6 ohm main towers, and the -8- 15" drivers in the bass towers which need minimal excursion none of the amps get stressed, especially with the efficiency of the class d amps. if my class D amps were conventional topography, and my speakers were a tough load of some sort, the load on my power grid could be double or more than what I have. and at that point getting 100% of the peak current needed at warp 9 starts to become an issue.

so amplifier efficiency is an issue along with speaker efficiency. a purpose built amp for the bass drivers has it's benefits.

the issue is 'headroom'. the more of that you have the easier the amps have to work and the more relaxed and flowing the music is.

and as I said in my first post of this thread;

I feel that the main issue involved is ultimate coherence.

Click to expand...

so getting back to your original question; the amp itself is secondary......it's more about how the whole system integrates. it's only after solving that problem that the actual amplifier performance becomes an issue.

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Everything makes a difference...... but sometimes not the way we think that they do.

A few years ago, I was exploring a new subwoofer amp design. The amp was driving a large (ok... huge) resistor as I was looking how it behaved at high loads. Changing the power supply of the subwoofer amp changed the sound of my system. It wasn't the quality of the bass that changed - the amp was driving a resistor. It was the quality of the midrange and high frequencies that changed because the subwoofer amp was plugged into the same electrical circuit. When I separated the main amp from the subwoofer amp by plugging them into separate Titans, the influence was still there, but far less.

This is one of the reasons why I went towards a Hypex module instead of an ICEpower module. The Hypex module is half-bridge whereas the ICEpower module is full-bridge. To supply the ICE, you need a 0-100V single rail. To supply the Hypex requites -50V 0 +50V. The cost of the power supply to supply two rails is almost twice the cost to supply a single rail. However, and this is an important however, the damage that the power supply does to the incoming AC supply is far less.

On an oscilloscope, you can see the single-rail supply gives the incoming AC supply a "flat top" when high current is drawn. With the two-rail supply, the damage is halved and it is symmetric.

Now you know the real reason. When asked why I use Hypex modules and not ICEpower modules in my speakers and I say "because it -sounds better" - not because the bass sounds better, but because the music sounds better. The actual sonic quality of the amplifier makes little sonic difference - hence the power supply for the Genesis subwoofer amps is designed to cause as little damage as possible to the AC since some customers may be plugging the speakers into the same power strip as their main amplifiers. If you took out my subwoofer amp and listened to it as a full-range amp, it would sound pretty awful.

Frantz, you may be skeptical about power cords making a difference in the sound quality of Mike's system, but the power cords are my design. They are not designed to be "the best power cords". They are designed to be the "proper interface" between the equipment and the outlet. This does not mean huge current carrying capacity or supremely low impedance. It means understand what a power supply does, and what an AC outlet does, and properly interfacing between the two. They are by no means universal. On some gear, they make no difference. On some gear, they may sound worse. But on some gear, they will make a big positive difference.

garylkoh said:

(...) The actual sonic quality of the amplifier makes little sonic difference - hence the power supply for the Genesis subwoofer amps is designed to cause as little damage as possible to the AC since some customers may be plugging the speakers into the same power strip as their main amplifiers. (... )

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Gary,
You are not the alone referring to this aspect - I remember reading an interview with an audio designer complaining that some digital amplifiers would create distortion and noise in the mains power lines and would seriously affect the performance of his equipment.

garylkoh said:

Everything makes a difference...... but sometimes not the way we think that they do.

<snip>

Frantz, you may be skeptical about power cords making a difference in the sound quality of Mike's system, but the power cords are my design. They are not designed to be "the best power cords". They are designed to be the "proper interface" between the equipment and the outlet. This does not mean huge current carrying capacity or supremely low impedance. It means understand what a power supply does, and what an AC outlet does, and properly interfacing between the two. They are by no means universal. On some gear, they make no difference. On some gear, they may sound worse. But on some gear, they will make a big positive difference.

Click to expand...

Garry

I love your speakers and am looking forward to audition the 5 and the 1 and e jr and the Dragon .. I remain more than skeptical about power cords. And this has been m position for the longest time even when I believed that cables made a "huge" difference and spent a ungodly amount of US Dollars on audiophile cables. I tested Power cables and never found them making a difference, i did find that the quality of the AC mattered and still believe so, using APC double conversion UPS for my current systems. Now if we are talking about the repercussions of different power supplies on the AC mains we are moving the goal posts. We are talking about what are the requirements for bass amplifiers and in my book it is power , stability, headroom and drive capacity IOW able to drive the transducers within their frequency range without distortion from the amp itself. And in the bass the Pro amps from the lowly Behringers to the Lab Grupen or Stellavox will do it as well as anything we audiophiles would like to spend ( a lot of )our money on and they'll do it with their run-of-the-mill power cords and radio shack fuses. I maintain furthermore that fuse contribution will not be audible in the region where a subwoofer is supposed to work that is under 70 Hz (Up there in frequency my position is the same but let's be nice and civil ) ..unless the fuse is totally bad or poorly designed

garylkoh said:

Everything makes a difference...... but sometimes not the way we think that they do.

Now you know the real reason. When asked why I use Hypex modules and not ICEpower modules in my speakers and I say "because it -sounds better" - not because the bass sounds better, but because the music sounds better. The actual sonic quality of the amplifier makes little sonic difference - hence the power supply for the Genesis subwoofer amps is designed to cause as little damage as possible to the AC since some customers may be plugging the speakers into the same power strip as their main amplifiers. If you took out my subwoofer amp and listened to it as a full-range amp, it would sound pretty awful.

Click to expand...

microstrip said:

Gary,
You are not the alone referring to this aspect - I remember reading an interview with an audio designer complaining that some digital amplifiers would create distortion and noise in the mains power lines and would seriously affect the performance of his equipment.

Click to expand...

there is a good reason I have filters to deal with back-fill noise on three circuits of my Equi=tech panel. the one for the digital player/dac and the 2 more for each set of subwoofer amps. no matter the class D amp there will be a certain amount of noise to be eliminated.

no doubt some class D amps have less noise than others, but they all tend to be noisy.

Mike Lavigne said:

i'm sure that somewhere there is a system with full range speakers which has added subwoofers that fully, completely, absolutely integrate. I've simply never heard one yet that does that.

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Mike-Am I missing something or did you just describe your speakers? You have full range speakers with woofer towers no? So do your speakers not integrate?

Mike Lavigne said:

n my system I have -4- Class D 1000 watt amplifiers on the bass towers, and then the two darTZeel 458's. that is 5000 watts to power potentially. with a 96db 6 ohm main towers, and the -8- 15" drivers in the bass towers which need minimal excursion none of the amps get stressed, especially with the efficiency of the class d amps. if my class D amps were conventional topography, and my speakers were a tough load of some sort, the load on my power grid could be double or more than what I have. and at that point getting 100% of the peak current needed at warp 9 starts to become an issue.

Click to expand...

In my system I have four 1800 watt Class D amps driving four 14" woofers which is 7200 watts plus the KSA-250 which can put out 4000 watts into .5 ohms. Somehow, I don't think the combination of all these amps can stress my power grid.

I'm also running a lot of power. I am running two, 2kW amps on my woofers, two 600W amps on my midranges and two 600W amps on my tweeters, and running them off a dedicated subpanel. Nothing is stressed. Each amplifier is on its own home run circuit and the sources and preamps are also on their own home run separate circuit.

I'll also say I have never cranked it to use all that power. I value my hearing.

FrantzM said:

Garry

I love your speakers and am looking forward to audition the 5 and the 1 and e jr and the Dragon .. I remain more than skeptical about power cords. And this has been m position for the longest time even when I believed that cables made a "huge" difference and spent a ungodly amount of US Dollars on audiophile cables. I tested Power cables and never found them making a difference, i did find that the quality of the AC mattered and still believe so, using APC double conversion UPS for my current systems. Now if we are talking about the repercussions of different power supplies on the AC mains we are moving the goal posts. We are talking about what are the requirements for bass amplifiers and in my book it is power , stability, headroom and drive capacity IOW able to drive the transducers within their frequency range without distortion from the amp itself. And in the bass the Pro amps from the lowly Behringers to the Lab Grupen or Stellavox will do it as well as anything we audiophiles would like to spend ( a lot of )our money on and they'll do it with their run-of-the-mill power cords and radio shack fuses. I maintain furthermore that fuse contribution will not be audible in the region where a subwoofer is supposed to work that is under 70 Hz (Up there in frequency my position is the same but let's be nice and civil ) ..unless the fuse is totally bad or poorly designed

Click to expand...

Frantz, thank you. I appreciate your candor. Less than 5 years ago, I was as adamant as you are now that power cables could make no difference - to the point of insisting that my customers use the supplied black power cords and not try to use anything else.

mep said:

Mike-Am I missing something or did you just describe your speakers? You have full range speakers with woofer towers no? So do your speakers not integrate?

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no, my main towers are not intended to be full range. they do have content into the 20hz range, but do not have the fullness and foundation in the lower bass that a full range speaker has, precisely so they integrate properly with the bass towers. it is an integrated system. not a full range speaker plus a subwoofer.

my point was simply that any speaker designed to have an audibly 'complete' bottom end is going to have a very difficult time changing that aspect of their character to not 'double' that same characteristic of any subwoofer.

In my system I have four 1800 watt Class D amps driving four 14" woofers which is 7200 watts plus the KSA-250 which can put out 4000 watts into .5 ohms. Somehow, I don't think the combination of all these amps can stress my power grid.

Click to expand...

exactly. since your class d amps don't put such a strain on the power grid you don't stress it.....which was my point. if you had four conventional topography 1800 watt mega amps that likely would be a different story depending on the efficiency of the woofers and how loud you played.

From a very interesting interview published in UltraAudio about active speakers:

Quoting Andy Payor "I find that one real challenge is educating the customer that, in a truly high-end system, it is unwise to use radically dissimilar amplifier topologies in a multi-amplified system. In an age where relatively inexpensive class-D amplification is often used in powered subwoofers, it’s sometimes difficult to stress enough the importance of having system amplifiers with the same transfer function if high fidelity is actually the objective. The notion that one can use a 15W single-ended triode for the main amplifier (because it doesn’t have to contend with making bass) coupled to a 1000W class-D amplifier for the bass may sound like the best of both worlds, but in practice it doesn’t work very well. This approach has been responsible for robbing the true performance potential of many a biamped system, as have poor setup and integration of levels within the system. Sometimes, when the flexibility and power are available, it’s difficult to resist turning the bass up to 11, even though it’s at the expense of natural tonal balance and a correct fundamental-to-harmonic-series relationship. . . . I make it a point to affirm that the active Arrakis has no “subwoofer” section, but that the extremely light, very compliant, low-distortion twin 15” woofers, each with approximately four cubic feet of volume, should be viewed as the foundation of the system, not merely an adjunct to extend bass. Because we are not attempting a lawless coercion of nature to extend the bass response, the integration is exceptional."

See it all at http://www.ultraaudio.com/index.php/features-menu/general-interest-interviews-menu/343-active-loudspeaker-systems-on-the-rise-peter-roth-talks-with-andy-payor-laurence-dickie-and-richard-vandersteen

FrantzM said:

(...) Any good subs (as in any thing in life there are good and bad) with appropriate crossover (read with phase control, flexible slopes, types and cut off frequencies) correctly set up will do (...)

Click to expand...

My little experience with a few subs and a microphone setup suggests me that a bass equalizer with Q factor, frequency and amplitude adjustment for a few frequencies is mandatory for a proper equalization in my room. And yes, a measuring system is also needed.

But I never managed to fully integrate a small speaker with a sub - as some people say the best speakers to use with a sub is one that does not need it. The best sub integration i have ever listened to used the Martin Logan Descent sub with Martin Logan Prodigy's.

microstrip said:

My little experience with a few subs and a microphone setup suggests me that a bass equalizer with Q factor, frequency and amplitude adjustment for a few frequencies is mandatory for a proper equalization in my room. And yes, a measuring system is also needed.

But I never managed to fully integrate a small speaker with a sub - as some people say the best speakers to use with a sub is one that does not need it. The best sub integration i have ever listened to used the Martin Logan Descent sub with Martin Logan Prodigy's.

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microstrip

No problem with the first part of your reply but do take a seocnd and reread your post.

a bass equalizer with Q factor, frequency and amplitude adjustment for a few frequencies is mandatory for a proper equalization in my room

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How would you accomplish this with a full range speaker? Are you suggesting to place an equalizer in the main signal chain? i doubt that is what you meant but ...
The reality of the situation is when facts clashes with belief or to be more precise belief systems because there is an audiophile core of beliefs, a system if you will. The physical fact is that the best position for imaging, soundstage and the rest of the spectrum is usually not the best for optimal bass reproduction. This is dues to physics and no amount of wishful thinking will change that. Thus we find the best compromise in separating the subs from the mains. There again audiophile orthodoxy wants the subs, preferably towers to be in close proximity to the mains... Often not their best positions for optimum bass. For the most part in most rooms virtually all speakers regardless of bass capability, need subwoofers, preferably more than 2 but definitely not one.
It should be noted that in the bass harmonics are often more audible than the fundamental. While 30 Hz is mostly a rumble its first harmonics 60 Hz can be perceived as low bass by most and is very audible. The third harmonics is squat in the region of high ear sensitivity 90 Hz and the fourth is 120 Hz .. you are getting the drift, thus for clean bass reproduction one needs a driver/amplifier with low distortion and power to control the cone (most likely candidate for true low bass unless you go rotary subs but then 20Hz is your upper limit ). You need the appropriate power to control the driver to maximum extension without the amp suffering and sending garbage to the driver. You want a strong and accurate amp. The notion of using similar amps will sound good to us audiophiles and we will find ourselves using extremely powerful tubes amplifiers on subs or woofer towers to “match" the mains. Not the best combo if you ask me and a waste of quality watts .. but the system will look impressive, cost a lot and sound reasonably good.. Although a Class D amp would have been a better match. Often when subs are used in a system, sight helping, many will claim a lack of integration and a bass “flavor” different from the mains sound. Often an honest assessment and an open mind would tell a different story. Anyone who has heard Steve Williams’ system can attest to that, the bass is integrated with the main despite the abyss of difference between the amps in the JL Audio SS likely Class D or AB, very high power with DSP for sure and the Direct Heated Triode SET he uses for the mains and I have had the same experience having lived very closely for over two years with Genesis speakers (the II and the V) which use their own bass amplifiers. The bass would take the "flavor "of the main amplifiers in all cases. You could even judge of the quality of the main amplifier bass performance through the Genesis although they have their own amp. Such is the case with a good subwoofer set-up. Steve Williams system uses subwoofer and the last time I heard it, was with the JL Audio Gotham (@Steve, I still regret you selling these by the way, they would have worked great in this room) there wasn’t a lack of integration to my ears, to Steve’s and most who have heard his system. I am speaking for myself here: the Magnepan integrated very with Paradigm subwoofers, I know someone on this board who uses MG 3.7 with cone subs. Additionally, many here use speakers with integrated subs and I have NO doubt their bass is well integrated. Jack D201, mep, Mike Lavigne, etc. come to mind.
Long post but to repeat my answer to the original question. Use a good powerful amp , it is good also to add a flexible crossover/Equalizer with your subs, Digital is good for the purpose the best commercial subs use digital EQ with great results ( paradigm Sub-1, JL Audio Gotham, etc) …

Thanks for the kudos Frantz but IMO those Gotham subs would have blown the walls out in my room as the Fathom subs come close to doing such now with the master volume up

In my last system it took me 3 months to get close to proper integration of the Gotham subs with my speakers. In this system only in the past several weeks have I brought this close to fruition as I was guided by my acoustician in the set up. It was with her mathematical graphing of my room with the speaker position in the room as well as the subs that she was able to give me the exact "phase" setting on the Fathom subs

Steve Williams said:

Thanks for the kudos Frantz but IMO those Gotham subs would have blown the walls out in my room as the Fathom subs come close to doing such now with the master volume up

In my last system it took me 3 months to get close to proper integration of the Gotham subs with my speakers. In this system only in the past several weeks have I brought this close to fruition as I was guided by my acoustician in the set up. It was with her mathematical graphing of my room with the speaker position in the room as well as the subs that she was able to give me the exact "phase" setting on the Fathom subs

Click to expand...

It is a matter of settings. If you set them up to blow the house they sure would. The point is that the Gotham would have been idling for the most part which usually translates into very low distortion in the operating range. But this is OT .. Back to amp for subs ..

FrantzM said:

microstrip

No problem with the first part of your reply but do take a seocnd and reread your post. How would you accomplish this with a full range speaker? Are you suggesting to place an equalizer in the main signal chain? i doubt that is what you meant but (...)

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Easy. Some of the speakers I am referring have by-wire capability for the big subwoofers - the Aida crosses at 55 Hz and the JMLab Grande Utopia Be at around 50Hz. If wanted, the main speaker sub can be driven also from the equalizer and separate bass amplifiers. And IMHO when using others such as the SoundLabs or the Wilson Audio X2 the speakers should be driven full range and the subs just to complement the main ones - it is why you need the equalizer with all its capabilities. Yes, no equalizer should be allowed in the man signal chain!

BTW, did you ever listen to the X2 paired with the Wilson Thor subs in a system having a similar quality to Steve's one?

Dear friends: I read it the whole thread learning about. If I want to add subs at any audio system with passive main speakers I will go for an active/powered subwoofers.

Active/powered subs are a matched integrated subs system where almost all are in control. When we are choosing for an amplifier ( any ) to mate it to a passive subs we and the amp have control over almost nothing and this means: higher distortions.

IMHO, any passive speakers ( including full range ones. ) benefit on added active/powered subwoofers and it does not matters the room dimensions.

This is something that I writed time ago but I think I can use it to explain my opinion about:

http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1117893153&openflup&27&4#27


additional there is something that we as audiophiles have to take care when we add or are going to choose " which subs are for my system? " and is the subs THD level.
Example the JL subs has around 10% THD at 20hz where the Velodyne has only 0.5% THD at 20 hz.

why that important difference between the JLs ( and several other subs. ) and Velodynes? because almost no one of those subs really has control on the movements of their woofers in all playback condition where the Velodyne sense aroun 16K times each second the woofer excursion to control it remaining at no more than 0.5% THD. Velodynes has a very good system that control each single woofer characteristic on normal or overloaded conditions.

other advantage on adding stand alone active subs :

http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1117893153&openflup&31&4#31

as a stand alone units the subs can be positioned in the room according with that room needs in the best position ( independent of the main speakers room position. ) that we can't do it with a speaker system that's integrated/monolithic.

Remember, adding subs main target is not to reinforce low bass.


Regards and enjoy the music,
R.