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OK I gave the RELs another look over. From what I can see they use mainly down firing drivers as opposed to the Rythmic using a forward facing driver.
I've always had forward facing and it is something I am familiar with.
My room is a 11.5x11.5 bedroom where the bed fills most of the room and it's carpeted. My speakers do go down pretty nicely to around 40-45Hz (just a guesstimate?).
I "think" I would like stereo subs. Only for the fact that it seems that the bed "cuts off" some of the acoustics having the sub on either side of the room or under a speaker. Having two 12" subs in a small room seems crazy!
Just intuitively thinking a downfiring sub would get lost in that room.
Maybe I should just build my own???
Follow Ups:
I'm using front firing diy stereo sealed subs (with 12" drivers) under my KEF LS50s in a nearfield small music room setup. They play like an extension of the speakers, and I feel in this case front firing is best.In the HT living room, I just built and added a couple of the Parts Express diy sub kits, using their 18" Utimax sub driver, matched up with the appropriate flat pack kit. Built in the downfiring position, mainly due to a new grand daughter and WAF. Plus I didn't have to mess with a grille. Placed them in the front corners, one is pretty tight (see above).
While I was setting them up, flipped them on their sides for front firing just to see if there was a performance change.The total output actually dropped 5 dBs at the same gain setting, when firing frontward. I'm assuming it was because they lost some of the natural corner gain.
Anyway, in this setup I get better performance downfiring, using a MiniDSP balanced unit for EQ. They "kick butt", tons of impact, which is what I want for movies
Edits: 12/04/16 12/04/16 12/04/16
And here is the music room subs. They are Rythmik 12" non-servo drivers built in a diy 2 cu ft./18" cube box each (back in the day when he offered both servo and non-servo models). Driven by an external pro amp.The boxes were designed so that I can upgrade to his servo model later, and use the balanced version of his plate amp, mounted in the back of the box. It will cost me around $1200 to do both. Plan on going for it, hopefully next year.
Edits: 12/04/16
My $.02I've been running subs for decades, along with biamping, triamping, etc. It started with car systems in the 70's as a teen (I didn't have my own place), then home equipment later on.
Currently I'm running two subs set up in stereo, crossed over at 40hz to a pair of biamped Heresy I speaks. I also have a single servo sub system set up in the mancave crossing over at 52hz to a pair of original Infinity Modulus mains.
As for the ability to locate a sub, sorry to burst anyone's bubble but even set to 40hz it's still an issue, and the reason I always run a stereo pair in a vehicle.
As for my single sub system, after many yrs of moving it around from place to place, even across the country, no matter the room it always sounds best located between the mains. And for the times when the room didn't allow a center location, corner placement aiming across the front wall was the next best thing. This along with proper adjustment of the variable phase can make the sub sonically replicate the sound of a center placement.
As for my reasons to run a stereo pair in the one system, it has little to do with most other's reasons. The Heresy is a great speaker that for me hits all the right notes, it just needs a bit more bass. Using two subs set up in the pictured configuration preserves all of the Heresy's attributes, it just sounds bigger. Sure the bass nodes still exist, they did without the subs too, but that's all a part of the speakers character I wanted to preserve. I wasn't looking to change the musicality of the Klipsch design, just make it bigger.
To this end my results were a smashing success.
All that said, not all subs are created equally. Even with two, the 12" Daytons acquitted themselves admirably but still fall short of the single 12" servo subs capabilities. Of course at more than 20X the price of one of the Daytons it should,
As for the original question of front vs down, I've always preferred the greater flexibility in placing the front firing over the down firing sub.
Martin
Edits: 11/25/16 11/25/16
In my experience down-firing subs load the room differently. I think they are less likely to excite room nodes so you get better in-room response. Whichever type you get, you can always turn it sideways to see if it makes a significant difference.
the nodes with the unaided ear while walking away from the subs to the back of the room. I then confirmed it with a Radio Shack decibel meter and located my listening position at one of the high spots. My HSU subs are not symmetrical.
I have not tried to listen for the high and low nodes with any forward facing subs yet.
1st order crossover =6 dB/oct
2nd order = 12dB/oct
3rd =18dB/oct
4th = 24dB/oct
The other variables are frequency and "Q".
If I was going to EQ the subs,I would use a parametric equalizer.
Generally speaking the top and bottom crossover frequency are not the same .Otherwise there would be no blending of the drivers.Unless the top-end and said subwoofer have the same roll-off in frequency response
If you hear the sub independantly from the satelites,your sub is either
(1)too high in level
(2) too high in frequency
(3) poorly located and may never simulate being connected to the upper frequencies
Tom:cat
with more than one sub, & reinforcing the need to filter quite low when using just one sub. So, thanks are due to all of you.I will be using 4 subs / bass sources soon, hoping to benefit from the 'swarm*' effect and using only enough Eq to trim it up. *? See Duke LeJeune's spkr systems.
The two front subs (sealed and stuffed and with P-P bass drivers) will each be under a QUAD ELS 63 fed at 150Hz 1st-order high-pass. The subs will be fed 3rd order low-pass @ 150 Hz to match and add in-phase. This set-up was recommended to me by TomServo.
I am beginning to think that it might be worthwhile to filter any additional subs at a lower frequency, perhaps 60 Hz.
This might give me a bit more wriggle room with positioning the 3rd and 4th subs, while still getting the 'swarm' effect down low.
The disadvantage might be working the main pair of subs a lot harder in the upper bass. So, I will try out both options.
I have sufficient power to cope with the power demands in the bass range, while using Eq.
i) Two high peak-power 100w RMS pc stereo SS power amps; a Fostex 300 which is also unconditionally stable into 'stats, and a HK 870. Both serviced, and able to do ~160 wpc when working hard, and
ii) a Perreaux 6000C, serviced and also able to cope with the QUAD's load, giving 380W RMS pc into 8 ohms. Peak? I don't know.
I have 3 x 1/3rd octave eq'rs and will soon have 2 more. Enough to Eq each sub to the listening area - if that becomes necessary. I am hoping that having 4 distributed subs I might be able to get way with one Eq'r per channel.
I may end up using the Perreaux to drive the sealed & eq'd front pair of subs, run the Fostex into the QUADs, and use the HK 870 into the TL subs I will be building next year.
Next Winter I will try my two LEAK Stereo 20s into the QUADs- rebuilt and rethought - parallel strapped to mono, in pentode mode, giving 40 WPC off both its '4ohm load taps' IE a '2-ohm tap.'
This place is a great resource with people like Luke, TomServo, and, most everyone else. :-)!
Warmest
Tim Bailey
Skeptical Measurer & Audio Scrounger
Edits: 11/09/16
REL is far too overpriced for their performance. Rythmik will easily out perform them in every category for a fraction of their price. REL may have been a good sub at one time but that time has long since passed.
Nice! airtime.
most here do not support REL? This is easily the best sub in the marketplace. Down or forward firing subwoofer(s) will not matter.
I do not like the floor standing loudspeakers that have a side-firing woofer.
REL is far too overpriced for their performance. Rythmik will easily out perform them in every category for a fraction of their price. REL may have been a good sub at one time but that time has long since passed.
Buy "Master Handbook of Acoustics" and "Why You Hear What You Hear".
:)
I once compared a HSU Research HRSW10 down firing sub(see AA pic from Trader) and a Velodyne UL15 down firing sub. They were placed in the same spot which is on my carpeted wood floor, on the 2nd story of a wood framed house. The HSU sub bass was much more distinct than that of the Velodyne. This could be due to the different design of the two subs. I also thought that maybe the larger, 15 inch Velodyne driver blasting into the carpeted wood floor created more back pressure thus muddying up the sound a bit compared to the HSU 10 inch driver.I still use the HSU stereo subs, but I want to eventually place them on concrete stepping stones to see if that will make the bass even clearer. I have done this at my second home out of state by placing stereo Polk RM1000 subs on 3 inch cement slabs from Lowe's(see second picture). These subs are also spiked and have heavy lead weights on the top. The bass from the Polk subs is very clear, and I attribute some of that to the cement platforms.
Anyway, my next installation attempt for better clarity would be to have forward facing subs with no near boundary influences like the floor. I might even place the Velodyne ULD15 on its side with its feet sticking straight out. Kind of like a big black bear sitting on its butt. Pretty ugly, but possibly clearer than a down firing arrangement. To be continued.
Edits: 11/06/16
The down fireing placement can cause a slot load type effect where the woofer sees additional cone mass loading and air compression. This can be good or bad.
... the down-firing subwoofer might make slightly more sense. In other instances, front-firing, bipole, dipole, or even up firing subs makes the most sense. YMMV, so evaluation and experimentation are key, as always.The down-firing sub could sound slightly more omni-directional (harder to localize) to your ears - depending on the room, the location of the sub, and the crossover point. And because the driver in a down-firing sub receives extra reinforcement by being only inches away from a major room boundary, it could sound louder than a front-firing sub of the same size and power at any given volume setting. And subwoofer plate amplifiers, especially the cheaper ones, sometimes exhibit less distortion at lower volume settings. Then aqain (as has been mentioned below), a down-firing sub sitting on very thick plush carpeting might lose some of it's output by way of absorption effects...
Front-firing subs offer a lot more more flexibility in usage than down-firing ones do though. A must for in-wall installations or whenever you must place the sub near a room boundary but do not want the driver to directly face one of those room boundaries.
Also, if your main speakers are small enough to warrant a high subwoofer crossover points (80 hz or higher) you might want the option of pointing subwoofer drivers toward the listening position (after you've placed each of two individual subs as close to the main speakers as possible). The goal being the best possible driver integration between mains and subs when higher subwoofer crossover settings make your subs produce some amount of uni-directional bass.
Up-firing subs offer more options for placement in some instances. It all depends on the room and/or furnishings within the room. HSU Research used to be one of the champions of the up-firing subwoofer design, but HSU seems to have changed it's tune lately...
Bipole subs react with room boundaries somewhat differently than simple monopole subs do, and this is one reason why some people say that finding optimal placement in a room is more difficult to do with a bipole sub. But bipole subs are effective "vibration-cancelling" designs - a plus in some situations.
Dipole subs, as one might expect, blend very well with dipole main speakers because they are "cut from the same cloth", so to speak. And of course, dipole subs also come with some of the same disadvantages as dipole main speakers. The two primary disadvantages of dipoles are that they usually need more physical space or "room to breath" than other types of speakers so, and the reduced output of a dipole configuration requires the need for much larger radiating surfaces (driver size).
So, consider the personal needs of yourself and your living partner(s), and the limitations imposed by your room and your speakers when choosing subwoofers. And rememeber that it can never hurt to ask your speaker manufacturer for specific recommendations.
Edits: 11/06/16 11/06/16 11/06/16 11/06/16
Sub woofers are simply omnidirectional due to the long wave lengths involved. And unless the crossover is very high there is no directionality to bass. In fact standing right next to a sub crossed over low(as a sub should be) even if the bass is booming away you will think the sub isn't even working. The bass will sound like it's coming from the main speakers. All the directional info comes from higher frequencies including the sub's harmonics. And that's not surprising; that's what the physics says. And yes I have experienced this affect. I've stood right next to subs cranking away and only heard bass coming from the main speakers multiple feet away.
You nailed dead on with your response. Bass is omni directional up to and including 80 Hz. The only advantage of a down firing sub is that the driver is protected from toddler's fingers.
You are right to say that the BASS is omnidirectional up to and including 80 hz. But the fundamental BASS frequencies are not all that you might hear from a subwoofer. Therefore 60 hz (or so) is as high as I ever go in crossover, if I can help it.Personally, I would avoid loudspeakers so wimpy that they might require a crossover setting higher than 60 hz.
I think that many would agree that it is usually best keep the crossover point as low as possible, for the reasons described in the above (and in the below) by both hahax and myself...
Edits: 11/07/16 11/08/16
Is that higher fundamentals of frequency are digitally filtered and sent to the mains.
Personally, I would never opt to feed the mains "through" the subwoofer. The cheap crossovers used in many subs are not always transparent enough, at least not to my ears.I have always found it preferable to run the mains full range, as long as they are not teeny, tiny mains such as NHT Superzeros (for example) and maybe even if they are. I simply wouldn't trust the crossovers in most subs to divide the signal accurately.
Patiently going by ear (one speaker at a time if using two subs) while feeding the sub it's own dedicated line level signal, I blend in the subwoofer(s) using the lowest possible crossover point and the highest possible volume setting. As long as I keep the crossover setting below 60 hz or so (usually, it's closer to 40 hz!), I never have problems with the subwoofer(s) calling attention to themselves.
Also, I think that subwoofers sometimes create their own harmonics. Cabinet and/or driver resonances, mostly. Once again, keeping the crossover point as low as possible helps with this.
Edits: 11/08/16 11/08/16 11/08/16 11/08/16
You guys are both generally on the right track. However, the focus on single-sub versus left and right subs, and crossover frequency/slope is misguided. For high fidelity sound reproduction, it is clear that the low frequency performance of the main speakers is critical. It's one thing to say that it's best to cross to a sub at 40-60 Hz, but if the mains crap out at 100 Hz, you're still going to have so-so low end. And, crossing at up to 60 Hz depends on the crossover slope. A single sub crossed at 60 Hz with a 12 dB/octave slope will still have localization problems, whereas one with a slope of 24 dB/octave will be less noticable. Also, this depends on the size and furnishings of the room.
The real important issue is to cross to the sub(s) at a frequency and with a slope which blends well with the main speakers. This is no different than crossing from the midrange to the tweeter - except for the wavelengths involved and the psychoacoustics - but the goal is the same: seamless integration of the drivers.
So, the concept/question of buying a "sub" or "subs" and where to cross over to it/them is secondary to the question of the capabilities of the mains. The mains will dictate the crossover and the one-or-two sub decision for you.
Put another way, the frequency at which it is crossed, and the crossover slope, is almost totally dependent on the performance of the main speakers in the low frequency range.
All too often, people think of subwoofers as an add-on. They're not.
:)
... that this was understood: When a crossover point around 60 hz or lower is used, the pair of mains must also have substantial bass output to 80 hz or below.For instance, early on in this discussion I suggested that tiny or bass-deficient main speakers might be best served by a crossover point higher than 60 hz and/or the use of two front-firing subs rather than one in order to fill in the missing bass and/or preserve stereo imaging, as needed...
No one I know would recommend the type of foolish "blanket approach" to subwoofer use that you describe. Not me, at least.
Edits: 11/08/16
The reason for two subs is to even out in room response, not for stereo effect.
Using measurements, I get the most linear response setting the subs to low pass at 70 hz - which allows for considerable output above 100 hz using a 12 db/octave slope.
The pair is used to eliminate localization.
What's that got to do with evening out in room response preventing or reducing peaks and nulls when walking around the room.
What's that got to do with evening out in room response preventing or reducing peaks and nulls when walking around the room.
I use a stereo pair to eliminate localization - that most annoying aspect of using a single sub since the most linear measurable response in my room dictates using a highish 70 hz 12 db/octave low pass - with audible output another octave above that.
Is eliminated by your crossover setting being below the threshold of localization, and not because you have 2 subs. The 2nd sub is there to smooth out the bass response in your room. Based on your pic, your only smoothing out the bass for a very small listening area at not for the whwhole room. That being said, I don't have a picture of the entire room so it may be working for you. Have you tried moving the second sub to another location to see if you could broaden the sweet spot for bass?
Edits: 11/10/16 11/10/16
In my living room, I tried placing a single sub in the available locations around the perimeter of the room but didn't get a satisfactorily flat response. The only good locations for a sub in my room which aren't in the way of foot traffic are at either end of the sofa. With the sub placed at one end of the sofa, and while sitting on the sofa next to it, it was still somewhat localizable even with a 40 Hz crossover point (mostly with HT effects, not so much with music). I solved this by placing a second sub at the other end of the sofa and balancing their levels by ear at the sweet spot. Now they completely disappear unless you put your head within 2 feet or so.
So I think using multiple subs can help with localization as well as evening out the response.
Hey 3db (which I would write as 3dB, but that's another topic), you're on the right track, but missing the all-important details.
Crossing below about 80 Hz, which is generally where we can start to perceive the source direction of a sound, does not mean that the "sub" does not produce output above that frequency. The "slope" of the crossover is just as important as the x-over frequency. For example, say the x-over is 60 Hz, with a slope of 12 dB/octave. This means the sub output is down 3 dB at 60 Hz, and is down 15 dB at 120 Hz. Without a calculator and the formula handy, let's say the sub output is down about 8-10 dB at 90 Hz. That is readily audible. That is one reason why two subs are often necessary, placed near each of the main speakers.
As I've written multiple times, buy "Why You Hear What You Hear".
:)
I use the AVR'S digital filters set at 80 Hz which I believe to be 2nd order filters with a 24 dB per octave roll off. Maybe that's the reason for not hearing any localization.
you don't understand how crossovers work or don't share my hearing acuity. I'll repeat my observation:
"...using a highish 70 hz 12 db/octave low pass - with audible output another octave above that."
Simple test Sparky - turn off the main amplifier and one sub while playing bass content. I just did that again to validate my earlier experience.
Perhaps you cannot localize sound an octave above that crossover point, but I can assure you that I can.
from you is nothing new especially when you feel challenged. I didn't mean to kivk your delicate but insanely large ego. Later sparkey.
Does your simplistic evaluation hold true in your room using a 12 db/octave slope?
I prefer the accuracy of digital filters to achieve my end results. Your so called tests are filled with sight bias. Your apparent lack of localization due to stereo subs has eliminated localization to one sub. However, the localization is now set to a pair of subs sitting in front beside your speakers. If I were to walk around your room, I would hear uneven bass response depending where I am standing.
Your so called tests are filled with sight bias.
How little your assumptions about me are accurate! I always close my eyes to evaluate audio gear.
In fact, one thing that annoys me about my Polk center speaker is that it is a two and a half way design. Which generally is a good thing and works fine in a vertical position. Although the cabinet is truly centered, I am aware that the origin of most of the sound is slightly to the right where the "midrange" driver is located. It would block the screen if I stood it up and it's as wide as the rack so I really cannot shift its lateral location nor the rack itself.
Your apparent lack of localization due to stereo subs has eliminated localization to one sub.
This is what I'm saying.
If I were to walk around your room, I would hear uneven bass response depending where I am standing.
Not only do I agree, I've measured it! Unlike my dedicated music room, the HT is in the family room where my options for placement are limited. On the other hand, I don't walk around the room while enjoying the HT. :)
Ideally, I would like to have a set of The Swarm designed by fellow inmate Duke LeJeune.
Congrats. That's great.
As I have always said, everyone should do whatever works best in their own system. For me and my stereo systems, lower crossover points have always sounded best.
If you are able to cross a single sub low enough to avoid localization, you most likely don't need one!
My standmounted mains go flat on their own to only 70 hz or so. Running the mains flat with separate line level to sub, a crossover setting of 40 hz, a 12 db sub slope, plus room gain, I get flat or slightly recessed bass response in the blended crossover region with beefy bass response starting down low at around 30 hz.Sounds about perfect to my ears, others might come up with different solutions.
Edits: 11/09/16 11/09/16
I think that most people here would avoid speakers so small that they output little or no bass below 100 hz (NHT Superzeros, etc...), but two subwoofers ARE sometimes necessary to preserve stereo effects with such speakers.Because stereo exists in at least some modern recordings from about 80 hz on up, using a single sub for a pair of very tiny mains like the Superzeros could cause you to lose that stereo info in the region of 80 - 100 hz. Unless you smoothly fill in the gap in response, that is. Granted, we're talking about a relatively miniscule loss of stereo info here but when listing to a recording of a solo male bass singer (for example), you probably wouldn't want to hear imaging cues toggling between two stereo speakers and a single subwoofer near the bottom of the bass singer's vocal range...
The way to fill in stereo the gap in such cases is to use two subwoofers, one for each speaker. Each subwoofer should be as close to the tiny main speakers "midrange/bass" driver as possible, in order to maintain maximum preservation of stereo info in the upper bass range.
However, if you listen exclusively to vinyl (or bad modern digital recordings) on a pair of Superzeros (or something similar) you should probably not worry about preserving stereo info in the 80 - 100 hz region, as recordings from the vinyl era typically had summed or mono bass from 100 hz on down. With vinyl, you can use only one subwoofer with a pair of of speakers like the Superzeros, if you are so inclined.
All that said, I would agree that two (or more) subs can also help smooth out bass response, at least in some cases. So two or more subs are almost always a bonus IMO.
Edits: 11/09/16
Given the number of threads and related questions about incorporating subwoofers (which I've always thought of as "woofers"), it would seem that your assumption is incorrect.
Otherwise, this wouldn't even be a topic.
:)
"Also, if your main speakers are small enough to warrant a high subwoofer crossover points (80 hz or higher) you might want the option of pointing subwoofer drivers toward the listening position (after you've placed each of two individual subs as close to the main speakers as possible). The goal being the best possible driver integration between mains and subs when higher subwoofer crossover settings make your subs produce some amount of uni-directional bass."
Although it's not "uni-drectional", I understand what you mean, and your understanding is basically correct.
:)
Yes. When I wrote "...*some amount of* uni-directional bass..." I figured What we understand stereo to be would be understood.
I too have felt but NOT HEARD subwoofers cranking away near me in a good room setup. So, I would agree that a properly set up subwoofer works as an omni-directional source. But..A "very high" crossover point, to my ears, is anything over 60 hz or so. Although it is said that bass stops being omni-directional after 80 hz or so. I suspect that air turbulence, harmonics, cabinet resonances, and reflections from room boundaries play a role in our ability to pinpoint a subwoofer's location when a crossover point higher than 60 hz. is used.
Down-firing subwoofers bounce air off of the floor in omni-directional fashion first of all (the so-called "slot-loading" effect). I suspect that this is why, if/when the crossover point hovers at 60 hz or above, a down-firing sub can seem more sonically invisible than a front-firing one of the same size at a similar crossover point.
Bu ultimately, I think it's a room dependent thing. I've tried down-firing and I've front-firing, and the above is indicative of my own personal experience.
Edits: 11/07/16 11/07/16
Its recording,room and system dependent. Eddie Gomez is in the far right corner of the room on DeJohnette ND live in Europe. But my systems dimensional array uses phase canellation.
ET
"If at first you don't succeed, keep on sucking till you do suck seed" - Curly Howard 1936
The REL's are forward firing with a bottom PASSIVE RADIATOR, which is what you're referring to.
look into hsu research, let me find a link, here you go:
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