Subwoofer speed is in the room, not the box
First, if you like swarm, that’s fine, please start a thread somewhere else about how much you like swarm.
I want to talk about the impression that subs are fast or slow compared to planar or line sources.
The concern, and it’s correct, is that adding a subwoofer to say a Martin Logan or Magneplanar speaker will ruin the sound balance. That concern is absolutely a valid one and can happen with almost any speaker, not just speakers with tight dispersion control.
What usually happens is that the room, sub and main speakers aren’t integrating very well. Unfortunately for most audiophiles, it’s very hard to figure out exactly what is wrong without measurements or EQ capabilities in the subwoofer to help you.
So, there’s the myth of a small sub being "faster." It isn’t. It’s slower has worst distortion and lower output than a larger sub but what it does is it doesn’t go down deep enough to wake the dragons.
The biggest problems I’ve heard/seen have been excessively large peaks in the subwoofer range. Sometimes those peaks put out 20x more power into a room than the rest of the subwoofer. Think about that!! Your 1000 W sub is putting out 20,000 watts worth of power in some very narrow bands. Of course that will sound bad and muddied. The combination of sub and main speaker can also excessively accentuate the area where they meet, not to mention nulls.
A lot is made about nulls in the bass but honestly IMHO, those are the least of our worries. Of course too many of them can make the bass drop out, but in practicality is is the irregular bass response and the massive peaks that most prevent any good sub from functioning well in a room.
Bass traps are of course very useful tools to help tame peaks and nulls. They can enable EQ in ways you can’t do without it. If your main speakers are ported, plug them. Us the AM Acoustics room mode simulator to help you place your speakers and listening location.
Lastly, using a subwoofer to only fill in 20 Hz range is nonsense. Go big or go home. Use a sub at least at 60 Hz or higher. Use a single cap to create a high pass filter. Use EQ on the subwoofer at least. Get bass traps. Measure, for heaven’s sake measure and stop imagining you know a thing about your speaker or subwoofer’s response in the room because you don’t. Once that speaker arrives in the room it’s a completely different animal than it was in the showroom or in the spec sheet.
Lastly, if your room is excessively reflective, you don’t need a sub, you need more absorption. By lowering the mid-hi energy levels in a room the bass will appear like an old Spanish galleon at low tide.
No. I want the sub to do the most it can do in the proper range to produce a fast, punchy sound (30 to 50hz). MORE gain not less. (BTW...16hz has no place in music.) Why would you do that? Just curious.
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A couple of experiences that I found to help. First is to identify what is fast bass? Where does this sound live? If you're looking for for bomb explosions and car crashes then 20hz is great but there isn't much of this in music. The deeper 'punch' for music lives in the 30 to 50 range. I want the woofers of my main speakers to participate. Experiments of plugging ports on main speakers has resulted in reduced excursion (restricts speaker movement) and lowered the volume output of the speaker and a LOSS of richness in mid bass. Not good. Let them remain open as they were designed to be. As the main speaker begins to drop off around 40 to 50hz this is the area for the 'SUB' woofer to help. Again, the main speakers will handle the upper bass no problem. My experience is that the subwoofer quickly becomes excessively 'boomy' at higher crossover settings above 60hz. (this depends on your main speaker capability) What works for me...My main speakers are solid bass down to 50hz. I set an EQ with a 'sharp shelf filter' cut off starting at 35hz. I do NOT want the main speakers OR the subwoofer to try and reproduce lower frequencies that it doesn't need. I don't need 20hz for music. It only adds distortion. Let the sub be focused on the proper range for tight bass. 30hz IS deep bass in music! The subwoofer 'low pass' is set to 40hz and will seam perfectly with the main speaker drop off at 50hz. Yes.. this is a tight range but I assure you it's the proper range for a 'SUB' woofer in music. The key here is that, within this tight level, you can now increase the 'gain' level of the subwoofer fairly high. Both my subs have gain settings almost 3/4 of the way up so when it calls for power it's ready! Punch of a kick drum is immediate and powerful due to an unrestricted gain level. You will never find tight punchy bass by setting a crossover high near 80hz or higher and then having to lower the volume to remove boominess. Like stepping on the brakes trying to go faster. That's completely backwards and is NOT what a subwoofer was designed to do. Good luck!
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You're right. It does on some speakers. However, let's look at a 3 way speaker. The high pass filter will only affect the woofer. The tweeter and midrange are already 'high passed' through the internal crossover. So the woofer, that is perfectly capable of producing excellent mid/lower bass, gets restricted by a high pass. Now you'll need to push the subwoofer to a higher crossover to compensate for the loss of bass. The subwoofer is not as good at producing upper bass as the high quality woofer you restricted using high pass. Another way to accomplish this sound improvement is by using a lower shelf filter cutoff around 35hz. Eliminating the lower frequencies that you don't need will improve the sound of BOTH your main speakers AND your subwoofer. This way you'll retain the full sound of your main speakers. It's a win/win. My ears much prefer the richer/fuller unrestricted mid bass sound without the high pass. |
After many, many tests...I respectfully disagree. So does REL. From REL..."Almost 100% of the time, newcomers will set the crossover too high and the gain (volume level) too low. This will result in a sound that is fatter, boomier and improperly integrated with the main speakers. The secret is to realize the crossover needs to be lower than the main speaker’s output at which point the gain can be significantly higher resulting in very flat, natural and extended deep bass."
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Just for clarification, I used your suggested high pass method for several years described in the article below. I worked directly with Barry so I'm VERY familiar with it. However, as committed as I was, I never achieved what I was looking for using this method. It was good but not great. Using my ears (crazy isn't it?) I concluded that if your main speakers produce good bass down to 50hz why restrict them? Why? Because it sounded better, fuller, more glorious. Plugging ports and making a sealed cabinet restricts cone movement. Makes the main speaker sound thin and anemic. IMO... if you want a sealed main speaker then it should be properly designed to work that way. Sealing ports and restricting quality speakers as an after thought is a mistake.
I want my sub to fill the void ONLY where it's needed. I want 'punch' in the area BELOW 60 hz. This is NOT an incremental improvement. This 'small zone' makes a huge difference. Subs need to "stay in there lane". Just because the sub is expensive doesn't mean it should do more than required to get your moneys worth. Upper bass is usually handled very well by the mains and the sub has ONE very important zone to fill. SUB bass, not mid bass. FYI...I did end up using sealed subs and MORE power to drive them. Tight with no ported bloat. Music not movies. Here's some reading you should find interesting as it outlines your method and if you're happy with it...that's great! I wasn't and found something more satisfying to my ears. https://www.soundoctor.com/whitepapers/subs.htm
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Is it just REL you think is silly or are all sub manufacturers silly? I just came back from the Tampa audio show and had this very discussion with SVS. They said they don't suggest higher than 50hz. Cutting off main speakers that are perfectly capable of producing deep base is something they don't recommend. Their words, not mine. Silliness prevailed.... I couldn't find ONE room where anyone cut the main speakers with high crossed subs. Not one. Many of the displays had NO subs and the speakers alone were more than capable of producing deep powerful (dare I say fast?) bass. Their display only used subs for home theater demonstration. 2 channel stereo was speakers only. So the question is...If the high pass method makes the speaker sound so much better, wouldn't every speaker manufacturer use this superior method? Are all these displays competing for high end sound missing the secret sauce that would make their speakers sound even better? Are they ALL silly?
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Yes. The majority of the speakers were very capable of producing strong, impactful bass without using a sub. So, they were fed the full unrestricted signal. So my point is why on earth would you restrict and high pass filter using any of these speakers when they are perfectly capable on their own? For this reason you don't see any restrictive high pass filtering method being used. @mijostyn Not wishful thinking, just a fact. Very simply put... these speakers are allowed to perform as they were designed by the manufacturer without any unnecessary attempts to make them sound "even better" by choking them down and adding complexity. @mijostyn ... I believe ALL speaker manufacturers are looking to "sell speakers" not just REL.
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Your subs look great. Are they push/pull or dual opposed? Have you ever tried precast concrete tubes? FYI..I don't use REL subs. I just use that crossover/volume method. My experience has yielded a great end result that's cheaper and easier and sounds great to me. An advantage of going to an audio show is you get to hear some of the best speakers in the world and then go home and compare. Otherwise the imagination can take take over in beliefs that are not based on reality. IMHO. |
