Subwoofer insight.


This is new territory to me. Current speakers are 2 way with frequency response of 60Hz-20KHz with +/- 2dB.  Sensitivity rated as 86dB. Chance to purchase a pair of REL 7 tis. I feel like I am missing something but will have to buy the subs to try out. My basic question is this. Does this purchase sound wise? I know what I am willing to spend but do you think I will notice an appreciable improvement.  I know that no one can listen through my ears but this is my first time doing this. Source is 75 watt integrated tube amp, McIntosh MA-2275. Thoughts appreciated. I am leaning towards going forward with the deal but would appreciate some feedback. Room is large and open, 28X38 feet with 9 foot ceilings. Thanks for any feedback.
ricmci
rwwear,
"The REL's just aren't real subs IMO. They don't even go down to 20hz. I have a friend with a pair of the REL Carbons. Even he acknowledges they don't perform like mine. I personally own Velodyne DD15s and I love them but would go for the SVS 16's if I needed a replacement. But you are right about personal preference Ric."
Have you ever heard SVS 16's or a REL in your system? 
We have different opinions about what's a real sub. I've owned SVS,  HSU, Martin Logan, JL Audio, and now REL. REL subwoofers don't thump like some subwoofers. In my system they provide different shades of bass and improve sound across the entire audio spectrum. In my opinion REL subs are very special with 2-channel, but they aren't the kind of subs that standout.   
No. I haven't heard them in my system but I've heard them in systems I'm well aware of. Setup is the key to making a sub work without thumping. The REL subs are decent but overpriced for less in many educated opinions.
I think after 30 years of experience and actually owning several subwoofers qualifies me as educated. Again, there are no absolutes in Audio, only preferences. So, I’ll continue to provide my opinion based on actual listening, but I won’t try to insult anyone that disagrees with me.
Okay. I have 30 years in the business of selling and installing systems and tuning them for many satisfied customers. I never intended to insult you Ric. I'm sure your system sounds good. I just know the RELs are twice the money of the SVS subs while getting less. If a sub can produce high quality bass below 20hz it has a much better chance of producing high quality 40hz bass.
Actually, the SVS 16s that you recommend start at $2000 each.  The question from OP wasn't about which sub to choose.  It was how to make the best use of RELs, which he bought.  That said, the T/7i that he bought currently retails at $900.  

Bringing the discussion back to OP, in my experience, the RELs are good for stereo.  I'm happy with mine, and honestly think that since adding dual REL subs, by system is better balanced at all FR and sounds better than it ever has.  We'd like to hear what you think after you get it all tuned in.

I will also say I"m a big fan of SVS.  My father asked me to help with his HT setup, and we got him a full set of SVS Ultra speakers and a pair of SVS 2000 subwoofers.  His system sounds fantastic, too.  For HT.
  • Sorry to the OP and I won't respond again. 
I don’t listen to any music that has bass any where near 20hz, let alone below 20hz. "I just know the RELs are twice the money of the SVS subs while getting less." You make your statement as fact, but it’s your opinion. I don’t want to defend REL, because I don’t have a financial interest in them. I submit "we" do a disservice to the audiophile community when we make comments like, "I just know the RELs are twice the money of the SVS subs while getting less." The truth is they’re different and to my ears, SVS just don’t produce different shades of bass. If someone said they required a subwoofer for HT and didn’t want to spend a lot of money I would recommend SVS. If someone said, they want a subwoofer that produces different shades of bass for 2-channel , that improves everything across the audio spectrum, I would recommend REL. If I had to recommend a subwoofer to someone with a dual purpose system combining HT with 2-channel and price isn’t a concern I recommend JL Audio.
My only reason for not buying a REL speaker is they don't dive deep enough. Notice I said speaker not sub....My SVS SB2000 can reach below 20Hz, has nothing to do about "hearing" this, its about feel and sustain of musical passages with deep notes.
My main speakers are prolly in the 35Hz range, why get a REL that is at 30Hz range, and pay 30-40% more.

Super pleased at what the SVS does to my 2-channel.....Proper setup is critical.
It only took this OP a couple of days before he quickly realized the undeniable shortcoming of old school set-it and forget-it subwoofers. Smart guy. 


I don’t listen to any music that has bass any where near 20hz, let alone below 20hz.

These low frequencies are inherent in the acoustic resonance of large spaces. Therefore present in all music that is well recorded in a large space. Its not "music" in the sense of any particular instrument playing it. Although this is definitely the case with a lot of music. But it is also there in a surprisingly large number of recordings of all kinds of music.

In other words its not that its not in the music you're listening to. Rest assured it is. Its just that your system is unable to reproduce it. If it were, you would experience it. Specifically, you would experience it as a heightened sense of envelopment, of being in the recording space, as opposed to merely being in your room. No doubt about it. Read the comments.
https://systems.audiogon.com/systems/8367
I appreciate all the responses. It has been a long stretch of working 10 nights. Now got 5 days off. Plan on trying to tune them in as best I can the next few days. Should be a good time and am excited to simply enjoy the music more than anything (no music except car radio for the last 10 days). Arghh! Might even try some of the alternative recommendations on connections that others have suggested here. Right now have connected as suggested by REL. I have been following this thread and even though it drifted off topic a few times and got over my head with building crossovers and the such, I appreciate everyone’s insight. Stay well.
Am I the only one that thinks this system is underpowered?  86dB 1w/1M on a 75W tube amp in a big space does not sound correct to me; I'd pick a good 200W/ch amp and see how that does.  I may agree with some of the sub comments, but you don't even have your main speakers set up right yet.  You won't know how the speaker really sounds until they are properly powered.

Underpowering speakers is the #1 most detrimental thing you can do to a speaker.  Running very long speaker cable runs is another, as those long cables suck all your power away and drastically decrease dampening factor so you get very poor bass performance.   so with a  75W amp, you don't have much room for error.  Try your speakers on a 1 foot length of 12 gauge OFC and see what happens.  Then borrow someone's big amp and try that, using your integrated as a preamp.  I bet its night and day. 

I work with speakers and amps all the time and I know from the ATC SCM19s i import, putting them on a small amp (say like a modern receiver, Denon, Yamaha, etc) they sound good.  Plenty of folks would be happy.  Put them on preamp with a big 200W or 300W amp (even if its a new Yamaha or Rotel or NAD -something like that) they sound like a different speaker- amazing!  Way more bass, way more dynamics, headroom etc.  If I tried that first, I might not add a sub.       

Brad
These low frequencies are inherent in the acoustic resonance of large spaces. Therefore present in all music that is well recorded in a large space.
Nonsense! It’s only present if the material was not filtered, which was often SOP for records. Any or all of the microphone, input channel, mix output, cutter could have been filtered to make the disk more playable.

OTOH, some unfiltered large space recording have enough sub-audible low end to put a plate amp sub into thermal shutdown. Adding a 12v 100 or 120mm computer fan run on ≈3.5vdc will keep the amp cool and dramatically extend its life.
see http://ielogical.com/assets/WinterBlues/Force_Fan.jpg Airflow is toward plate to force air up the channels.
The fan is held in place with the compliant mounting plugs. Even Saving Private Ryan or Telarc 1812 w cannon won’t shake it loose.
ricred1
I don’t listen to any music that has bass any where near 20hz, let alone below 20hz.

millercarbonThese low frequencies are inherent in the acoustic resonance of large spaces.
Huh? You must be hearing things!
I suggest you try and measure this "inherent" acoustic resonance. Feel free to report back with your findings.
Thanks Brad, easier said than done. I have often said to myself the same question. I know no one whom participates in these activities so borrowing is not an immediate option. Sure, I could make a local effort and see what is available but that is not who I am. Sure, I could use more power and more efficient speakers. To my ears the sound is quite pleasing. I’m sure I could hook something else up and be hooked. I don’t plan on that until I have to since quite happy with what I have. Just trying to optimize what I have.  Wasn’t looking to redo my system.  As said earlier, you only know what you know. Knowing more does not necessarily make life less complicated. In this situation, it actually makes it more complicated. Today, I listened to a DMB vinyl box set (1998) I bought for my wife as a present and just loved it with subs on rather than off. I don’t need perfection. Listening to it on my system sounds 99 percent better than anything else I have ever heard. Not saying 99 percent better than what everyone here has. Far from. Just saying 99 percent better than “The best of what’s around”!
ATC SCM19 has a published spec of
Frequency Response (-6dB): 54Hz-22kHz
Even 1000w is never going to get low end from it or any similar 2-way.

Power requirements fall approximately 50% per octave. Using the SCM19 as an example and rolling the bass @ 80Hz requires an amplifier of only 50w vs 200w full range. The smallish woofer is relieved and more easily accomplishes its task as a mid -bass & -range driver. There is no free lunch and no 6" driver is ever going to have the same output at 20Hz or even 40Hz as at 200Hz or 2kHz in any box of reasonable size.

A purpose built sub with 300w RMS peak has double the power necessary for the 20-80Hz range as the 50 for 80-20kHz. Something in the 10-12" range with similar sonics to the mains & properly set up will add musical realism beyond any amount of power.

IMO, unless one has completely separate HT & music systems, one should opt for musical sub[s]
REL is going to reproduce the subtle spacial nuances in both music and home theater in ways that level up your experience and your system as a whole. As Ricred posted earlier, he's had a number of different subs and ended up with dual REL Carbons.

I have another friend who bought a REL Carbon as well and liked it so much he added a 2nd. 

There's a reason you see RELs with 2 channel high end systems at the shows.
There's a reason you see RELs with 2 channel high end systems at the shows
where some of mostest, awfulest sound on the planet is purveyed.

IMO, any sub w/o a continuous phase control, polarity invert and multiple slopes is a toy.
There's a reason you see RELs with 2 channel high end systems at the shows.
Better profit margins for the dealers?
There's simply a level of nuance in spacial reproduction that the other's don't match. There is much more to a sub-woofer than going thump really loud at 20 hz.
Hi

Just went through something similar. Got some good advice here, which I implemented yesterday with great success!

Thread is here, might be worth your time looking at:

https://forum.audiogon.com/discussions/active-line-level-crossover-with-subwoofer-out-help?lastpage=...
Spacial reproduction has nothing to do with REL, or any particular sub for that matter. Whoever REL has hired for marketing isn't being paid enough. Anyone capable of that degree of mind control ought to be working for CIA or the Fed, its just astounding. Fully expect any day now to be reading REL has cured the common cold, brought peace to the mideast, eliminated dandruff and who knows maybe even cancer. Its just nuts.

Truth is any 4 subs spaced asymmetrically around the room will get you there. My system has 2 sealed, 2 ported, and one powered, and read the comments the bass is incredible, totally integrated, and 3D. This 5 subs completely disappear, the bass is as beautifully imaged as all the rest, and this has been the case no matter where they are moved ever since going from one to 4, and finally 5.

Sorry. Not saying REL doesn't make a good sub. Simply saying REL doesn't make a good enough sub for one to be better than 4. No one does. You want good bass, you get 4. Its that simple.
Of course the RELs sound more detailed because they are producing less music that would otherwise compete with the higher bass frequencies. The less bass a speaker produces the more detailed they seem. By saying you will never play anything with bass around 20hz you are writing off a lot of great classical, rock, electronic and modern pop such as Dutoit's Planets to the likes of Billie Eilish, King Crimson, Pink Floyd and many others. And as I said earlier, a sub that can reproduce below 20hz can do a much better job of reproducing 40hz.without strain. No decent sub will thump if set up correctly.
03-26-2020 6:50pm
spacial reproduction
What exactly do you mean by that?
Exactly.

The subtle details that make up the recording studio, the reflections of certain notes off the walls or ceiling, the subtleties of a breeze or noise coming from a nearby building that ’frames’ the space of the original scene sonically. Those subtle sounds and noises reproduced in the mid bass and bass are what helps to recreate the original sonice picture.

RELs do that with their high level connections, and an adjustment system and filters that help you dial them in so they Blend with your main speakers seamlessly. In my experience RELs help you reproduce the music or soundtracks much better than your mains do by themselves.

...Or you could build your own set of 10 or 15 world class subs from scratch like @millercarbon says he has. ;-)


rwwear2,721 posts03-26-2020 7:49pmOf course the RELs sound more detailed because they are producing less music that would otherwise compete with the higher bass frequencies. The less bass a speaker produces the more detailed they seem. By saying you will never play anything with bass around 20hz...
Fake news.
My experience with both Sunfire, Sunfire Signature, and SVS Ultra and Plus is that most subs do not integrate well

Check out GR-Research. He seems to be onto how to make them

hth
I don't think OP started this discussion for you guys to come in and bash his system or his choice of equipment, or for you to argue with each other.  Really, this forum has become such a slug-fest it's unbelievable!  If some of you actually knew as much as you think you know, you could save the world!  You even have him believing that you know more than the engineers and designers at REL, who designed these subs!

OP has nice equipment!  His choice of Mac is great, and it's not underpowered.  75 tube watts from a Mac is a lot of power.  They use excellent transformers and excellent design.  They will power those 86db speakers just fine.  The RELs are good subs.  No, they don't go to 10 Hz, but neither does the music!  

Sure, a new amp, 4 big subs (or is it 5 now, MC?), new, more efficient speakers, and tweaky fuses, cones and power cords would make it sound different (not necessarily better).  But, that's not what he asked.  His question for you guys was whether or not he will see improvement by adding the RELs to his system.  He isn't living in an anechoic chamber, and isn't looking for perfect, world class sound, and he isn't building a studio or trying to spend tens of thousands of dollars!

The answer to the question, @ricmci is YES!  It will definitely improve things for you, and I think you have already discovered that.  IME the RELs are very musical.  They integrate very well with your speakers if you take your time in tuning them, and I recommend following the OE instructions to connect using the high inputs.  Are they the best available?  No.  Are they junk?  Far from it.  In my case, I have Primaluna HP Integrated with Revel F208 speakers and a pair of REL t/9i subs.  The SQ is fantastic!  

Some of the forum regulars need to grow up.  It's like OP came in asking if he should paint the walls blue.  And, then this group gets hold of him and tries to convince him blue is wrong, and he should move walls, raise the roof, and move to Colorado where the power grid is more reliable.  If he's happy with what he's got, then let him be happy!  He is taking a journey, as we all are.  Instead of encouraging his walk up the hill, you want him to go to the moon.  Sheesh.
You have a point Sounder. Just pointing out cheaper and better options.
Chaz, it’s not fake news. Try listening to a simple acoustic recording then a complicated classical piece and see which seems more detailed.
Tweak, any quality sub can be integrated into a system if setup correctly.
any quality sub can be integrated into a system if setup correctly
define integrated

More ≠ Better.

Without multiple slopes, phase, polarity and optimally delay integration will suffer except for a very small subset of mains.

IMO, some units are jewelry aimed at the ignorant. From where they were 20 years ago, REL has definitely moved in that direction. Chrome feet w logo. PuLeease!
rwwear2,722 posts03-27-2020 9:09amChaz, it’s not fake news.
It is fake news.
A single Rel 812 se is -6dbs at 19hz.

https://rel.net/shop/powered-subwoofers/serie-s/s-812/

What REL's do better is reproduce the subtle mid bass sonics and details and integrate that with the mains.
define integrated

Integrated means of one piece, whole. Its a fact. You could look it up. Bass is integrated when its impossible to tell there are subs, or even any speakers at all. Integrated is when the bass is so clean and clear and extended you are enveloped to the point where the walls of the room dissolve and you feel you are within a holographic acoustic space.

This is impossible to achieve with any one sub. The more subs you use the easier this becomes. With four or five subs it is trivially easy. Virtually any four subs located virtually anywhere in the room will get you there. No single sub located anywhere will. Not even two. More is better.

https://systems.audiogon.com/systems/8367

Would be very interested to hear ieales tell us all how many four and five sub setups he has tried, in order to fully evaluate his credibility on the subject.
You guys won't give up.  MC you have a one track mind!!  I don't see any comment in this thread saying you only need one sub.  The OP actually has 2.  

Then ieales insists on something super complicated, or it's not even good enough for him to discuss (making me wonder why he keeps discussing it). 

Since when does a logo and chrome foot (actually mine don't have chrome feet, they are aluminum) have anything to do with the quality of the product?

You two should get together to talk about how right you both are.
Chaz, - 6 @19hz is getting closer. Now if REL can just go a little lower for less $. The RELs are pretty though.
@soundermn 
I bin doin' dis a long time.
I got da tools.
Tryin' to set up subs w ½-arsed controls is a YUGE PITA.

IME, high level inputs w a toob amp is a bad idea. Transformers are current devices and many speaker impedances are all over the map in the low end, causing similar input vagaries to the sub. Ergo, the sub is mimicking the eff'd up main low end. BTDT.

Roll the low end out of the mains. If they were any good in the bottom, subs would not even be an issue.

My tongue is about an inch short from all the times I've bitten it when subjected to systems with ½-arsed subs.

=======================
As a composer friend once said on hearing my phase correct sub:

Those little speakers aren't putting out all that gorgeous bass?!?!?!?!?

- No, there's a subwoofer at the end of the sofa. -

Every other subwoofer I've ever heard just boomed!

Almost...
=======================

Others on later phase correct systems:
- Joe Pass is sitting right there!
Man, your system is so precise!
- etc.

 
I’m so sorry ieales but I don’t understand what you are trying to say. Read it multiple times but still don’t get it. Any chance you could say it without the subliminal messaging?
He is trying to say the REL subs are junk and that I have them hooked up wrong, even though I did it exactly as shown by the designer.   Obviously he knows way more than the engineers at REL.    You can tell by his mastery of language. 
https://rel.net/how-to-connect-your-rel-to-a-tube-amplifier/

https://relsupport.zendesk.com/hc/en-us/articles/115005872647-Stereo-RELs-Tuning-Guide

It is common for vacuum tube power amplifiers to have three sets of output connections. Since the REL high level connections draws no current, it is best to use it with taps intended for driving higher impedances such as 8, or even 16 ohms.
We suggest starting by connecting the RED and YELLOW “hot” wires of the REL high level cable to the 8 ohm speaker outputs. This is recommended even if your main speakers are connected to 4 ohm (or 2 ohm) outputs because the gain of RELs is designed to follow the longstanding industry practice of using 8 ohm as a standard. Selecting a lower impedance for the REL connection will result in MUCH lower output. 



Hi Ric,

I believe what Mr. ieales is trying to tell you is that REL subs are more difficult to integrate into a system than other brands of subs because they do not have variable phase adjustability. Phase in this case basically means that the output signal of the sub starts (or maybe I should say arrives at the listening position) at the exact same time as the output signal of the other speakers (including any other subs) in the system. In a single box speaker this is all controlled by the internal crossover. With a sub woofer and satellite speaker setup that crossover does not exist so that phase/time relationship between the sub and the main needs to be controlled in a different manner. One of the easiest and probably most economical ways to achieve this is by adding variable phase control to the sub amplifier.

REL's phase control allows you to vary the start of the signal in two increments where as other manufactures allow you to vary the start of the signal in as many as 360 increments.  It's kind of like using a ruler with markings at 0", 6" and 12" rather than using one that breaks down each inch into 1/32" segments.

Why REL does not include variable phase adjustability with their subs I do not know, I have a couple of guesses, but ultimately I do not know. OTOH there are a lot of very satisfied REL owners. So what does that mean? Who knows and for that matter who cares. I do know that you don't always need to measure to 1/32" to get the job done but if you can usually the end result will be better.

The bottom line is, do you like what you are hearing? If you do, that is all that matters.
MiniDSP could be employed to integrate the subs if one wanted to get more involved than a simple setup. https://www.minidsp.com/
That is a big room, you got anything smaller, you can treat without getting the partner upset? Does it have to be that room? There is no fix without room treatment of some kind, or just use part of the room, Can you use partitions? Fold out while in use and back when not. Servo bass? OB servo bass, pressures the room a whole different way.  If I had a room that big, there would be at least a 1000 lb of speakers, just for the mains and another 1000 pounds for bass units. That put it in better perspective...BIG room, BIG speakers, more work...

Regards
A lot of overly complicated, unnecessarily redundant information being spread around here.  MORE IS NOT BETTER!  Insanity may dictate otherwise, but keeping it simple makes it easier to control the Q in your listening room.  Quality, fewest connections possible and patience with the setup will go far.  REL Speakon connections are THEE best way to add a subwoofer to your system for 2 channel quality sound reproduction.  Use “LIVE” recordings to dial in the presence and atmosphere that your system can deliver.  REL has very good placement advice, but experimentation is key...corners are bad!  Mine faces front and is roughly in line with the mid driver on my main speakers.  Your room will dictate which is best.  Use bass heavy acoustic music to dial the sub in, repeating familiar tracks till you are satisfied.  It’s actually not that hard and fun to do when you have some extra time to tweak:)
I did not say REL are junk. They have moved into the HiFi Jewelry market adding things which do nothing for the sound and leaving out things that would.

Phase
=====
To get low end out of a small woofer requires adding EQ to the amplifier which adds phase shift and group delay. Sound has magnitude and phase. This is why an out of phase pair of mains sounds the way it does. The amplitude is the same, but the phase is 180° out. The VECTOR sum is zero except for driver and room anomalies. So to integrate a sub, one needs both level and phase controls for the best VECTOR sum. A 180° polarity inversion is the equivalent of moving the sub ≈14 feet @ 40Hz. And a different distance for every other frequency.

Note that a phase control is not a perfect solution, it's just that it's next to hopeless without it.

See http://www.ielogical.com/Audio/SubTerrBlues.php for further explanation.

Tube Amps
=========
The REL instructions are either written for or by someone with ZERO understanding of output transformers.

Google stereophile phase in Images. Notice how the impedance rises in the low end of most speakers. With an output transformer, when the load impedance rises, SO DOES THE OUTPUT VOLTAGE. Since the REL SpeakOn input is high impedance, the sub output will increase due to the increased voltage even though the amplifier input signal does not change in level.

For the gazillionth time, roll the low end from the mains with a simple 6db/oct passive xover about ½ to 1 octave above the mains -db frequency  and drive a sub with multiple XO slopes, phase and polarity controls into the LINE input.

Follow the interface guidelines under Setup at  http://www.ielogical.com/Audio/SubTerrBlues.php.
There are links to model your room, main and sub placement. REW https://www.roomeqwizard.com/ also has good modelling.
More stuff in the signal path means further degradation or alteration of the signal.  Simpler is better.  The mains and sub(s) should be receiving the exact same signal for maximum fidelity.  REL Speakon connections do that.  Adding EQ and crossovers and more wires and different levels with various impedance mismatches...ugh!!  For Cinema/HT?  Ok 👍. For purist 2 CH Home Stereo...keep it simple.
^^ Nonsense.
Adding wire to the SpeakOn adds L&C to the speaker main amp circuit.
Using an XO reduces the main amp load, increasing dynamic range and reducing distortion from the main loudspeaker.

I agree there is no free lunch, but High level from the full bandwidth main is not how any pro studio or sound reinforcement system is done.

It's a bad joke foisted on the ignorant looking for a free lunch!


Speakon connectors are just old timey high level speaker connections like we used in the old days when receivers didn’t have sub outs. Maybe it’s great but seems archaic. Most subs still have high level connections for older receivers I suppose.

I would still run my mains full range. The less electronics the mains go through, the better they will sound.
No Electronics.

Passive XO with teflon or polystyrene or polypropylene caps. The best RCAs. Wired with silver plated teflon coated wire and Ag solder.

Listen to something with no low end like a Cecila Bartoli aria or Winton Marsalis solo. I defy anyone to hear it.

With well mated subs, the increase in mid bass clarity has to be heard.

See http://www.ielogical.com/assets/Audio/PassiveXO1.png
Without killing your budget I'm running a pair of small Sumiko S.0 subs with my Totem Tribe towers... It provides the perfect amount of punch needed for my dedicated 2 channel system.


The REL’s are powered geniuses ...they draw almost nothing from the amp via the Speakon connection.  Mains run full range.  No X crossover needed.  No extra interconnects.  No extra boxes with crap in them for the signal to be degraded.  Simple!