What are the benefits of a front-firing sub-woofer (if any) vs. a down-firing? Some have suggested that a front-firing sub may be easier and more flexible in it's room placement. Has this been your experience?
Sub Bass should not be directional. It should sound like it's everywhere. I have a Rel B3 which is front firing with a downward port. That said I personally find if I place the front of the sub firing to the left (it's on the right of my right speaker) it sounds like it's coming out of both the right and left channels and is pretty even throughout my room. If I face it right at me either in that position or between the speakers the sub bass seems less except if I walk around the room. Yep I have a pretty bad room... So I would think down-firing would easier to setup and place. I also only add to what my main speakers can't reproduce and NOT ADD to it (then it tends to get directional meaning I know where the sub is).
The main advantage of a downfiring is you get a lower freq. in your room. We Always call them party subwoofers. They can give a lot of fun. But....are they accurate? Not really!
Front firing is much more accurate and also realistic. When the subwoofer is sealed the timing is faster. Speed is the key to the best integration for a subwoofer.
The best subwoofers are Always sealed and have frontfiring. With these kind of subwoofers I can create what I call stealth integration. I only can achieve this with Audyssey Pro. Then you have a full integration witht the subwoofer. The energy is comming from were it is on the recording.
It is literally impossible to hear a subwoofer in a room without hearing the room. By the time your ears have heard enough full cycles to detect the pitch, those long wavelengths have been around the room several times. Point being, it's always subwoofer + room that we hear, never just the subwoofer.
So what we want is a sub that synergizes well with whatever the room is going to do to it. Assuming we're talking about a single sub (there are major advantages to using multiple smaller subs, but I don't think that's on the menu here), probably the best we can hope for is a sub whose native response is the approximate inverse of room gain. That way, sub + room = neither broadly rising low end, nor broadly falling low end. We'll still have major room-induced peaks and dips, but that's another problem for another day.
Neither front-firing nor down-firing have any significant advantage as far as room interaction. Box and woofer being equal, the air mass underneath the cone will change the effective woofer parameters a bit, resulting in a slightly "fatter" low-end from the downfiring iteration, but that just means the designer would start out with a different woofer and/or different enclosure in order to meet a given target.
Back to subwoofer performance targets for a minute. It's been mentioned that sealed subs are better for high quality sound, and the presumption is that that's due to their superior transient response. But the ear's time-domain resolution at low frequencies is extremely poor (which is why we can't localize the source at long wavelengths - our two ears don't detect the arrival time differences down there). It's not really the transient response itself we are hearing; rather, it's the in-room frequency response (something our ears are very good at hearing). Vented sub + room often results in a rise in the deep bass, which sounds "slow", whereas a sealed sub + room tends to have a gentle falloff in the low bass, which sounds "fast".
You see, typical broadband room gain due to boundary reinforcement is approximately 3 dB per octave. So, based on the room + sub paradigm, we'd arguably want the sub's inherent output to fall gently at 3 dB per octave as we go down the bass region. This way sub + room = roughly "flat" (aside from room-induced peak and dips). Vented cabinets are often tuned for deepest loudest bass, so the room's +3 dB per octave tends to make them sound boomy. Sealed boxes typically start rolling off higher, but it's a gentle rolloff, often between 6 dB and 12 dB per octave, so it synergizes better with the room.
As proof that it's the sub + room, and not the sub itself, haul both subs outdoors. Now the sealed sub sounds weak and anemic, but the vented sub sounds faster than it did indoors - now the vented sub is clearly the qualitative winner. These are generalities, of course - there are exceptions.
Imo vented sub technology has the greater potential for good in-room bass because a vented sub can be designed to gently roll off by approximately 3 dB per octave from 80 Hz down to 20 Hz (before room gain), whereas such performance is not really possible from an unequalized sealed box.
Sorry for the long digression, and I know that's not the question that was asked. The imo theoretically ideal 3 dB per octave native rolloff can be realized with either a front-firing or a down-firing sub. So it's not driver location itself that matters, it's the overall system design and how it synergizes with the inevitable effects of the room.
I understand your story, but.....with the use of Audyssey Pro ( my way which it a lot different compared to the Audyssey way) I can play so much louder than without. Even with the most dynamic music I do not have the problems I had in the past without it. It feels like freedom because the limitations are almost gone.
Time changes and technique as well. I have proven that I have created a much higher level of integration. A few surround specialists has been here to listen to it. They were amazed that for the first time that what I call Stealth integration is possible. One surround specialist said; You have gold in your hands.
I use my subwoofer from 16 hz till 140 hz. The energy is so much better placed than most people can imagine. It is exactly comming from were it is, and it is more one with the speakers.
When I do test at clients there home without Audyssey Pro they all fail. They also have acoustic limitations. The integration is of a much lower level.
Using Audyssey Pro, Purist Audio powercables, New Wild Dog subwoofercable from Audioquest sets a subwoofer to a new level of integration!
The level of integration is the key to succes in integration!
What about dispersion 'efficiency' of a front vs down.
It would seem that a down firing is sending output in all directions - to the sides and the rear - and resultant interactions and add'l reflections with the front wall, equipment to the sides. Whereas a front firing would be more efficient at beaming energy/content into the listening area.
Just guessing....never tried any tests - but it is something I've wondered about front vs down firing.
Hi guys, I've been building speakers for 35 or so years, Dukes Explanation is accurate. I personally prefer a sealed sub when done correctly and well placed in a room, but vented/ported boxes have a better chance of easy setup. As far as Dispersion? Duke handles that when he talks of wave length, travel time etc. Bass has been around a room a couple of times by the time you hear it, that's why it has time to interact with the room and muck everything up. Bo is speaking on another level by adding an EQ/DSP room correction software. With this, you can analyze peaks and dips in your room and correct them electronically. Bo is doing something that I've never heard sound great in a 2 channel high end system... Crossing at 140hz... I normally target anywhere from 40 to 100 depending on room interaction, main speakers natural roll off or electronic crossover and the powered woofers own crossover slope on the top end... I hope this helps, Tim
I have a sealed downfiring REL, but I turn it upside down and use it upfiring. I find this to produce a more accurate, and quicker sound in my room. It's not in a corner either, but between the speakers. I do place a board on the upturned feet with something heavy on top of that.
I sold in the past many many REL subwoofers. The material of my PLW-15 is made from ceramics. This is a lot lighter compared to the material REL is using. This makes a big difference in response. I have told this a few times.
It is very easy to understand when you hear the difference in response. Subwoofers can reach a much higher level for integration when the material is lighter.
Timing is the key for succes regarding integration!!
Quote: "It is very easy to understand when you hear the difference in response. Subwoofers can reach a much higher level for integration when the material is lighter"
Cone mass in itself does not change response, you must have a motor structure to match... lighter mass in itself offers low QMS/QTS, which in turn requires ported or vented boxes... Adding mass lowers FS and raises QMS/QTS, kinda goes against your theory of must using a sealed box... of course you can use less motor structure, but now you deal with a higher FS and VAS problems... The entire driver is a balancing act... a lighter cone material in itself does not tell the story. Not trying to start a war, but those are the facts
Clearly Duke and Tim do not have enough sales experience to know how a subwoofer works. But it is fun to watch Bo school two guys, who actually know how to build a speaker, on the finer points of subwoofer design. I for one hope it continues to see how deep the hole gets.
Audio is a lot more than only building it. Even at many shows often a subwoofer does not have a belanced sound as it should have. Even when the manufacturers are there at the show.
Often at shows they tell a nice technical story ( at their own frequency), but the demo is not even convincing. Hearing is believing.
They should tell about their products on the same frequency customers think about audio.
What do I hear....this is what counts!!
The people who make things often use a few brands to test. I have often asked brands like Pass Labs, Nordost and Audioquest people about their knowledge in other products of competitors. And different sources and amps they use with their own products.
I was often surprised that they knew less than I thought.
That is why I said a few times; there need to be more communication. The endresults in sound needs to get to a higher level. They need to work more togheter!!
It is a person who developes the pre amps. We talked about cables. At shows they used often cables which give a wide and deep stage. But with Pass Labs you need other properties. You need a more intimate individuel focus.
Even big brands in cables they did not test or use. Those are the ones which give a much better endresult compared to the ones they use. We had email contact about this issue.
Nelson makes the best poweramps in the world in my personal opnion. For me he is God in amps.
What you're not getting is that this forum is Bo's personal web space for hawking products that in his sole opinion sound good. With amazing consistency and dogged determination he uses the forum to promote products he sells. He does it openly and with no shame. While others may attempt to help others and offers their experiences as lessons, Bo knows to keep hawking.
"And when you pray, do not be like the hypocrites, for they love to pray standing in the synagogues and on the street corners to be seen by others."
Interesting to see Bo keeps on preaching Purist Audio (which is IME a good company) anytime / anywhere and against NordOst anytime / anywhere). That record sounds definitely broken.
Bo's thoughts on woofer "speed" are based on some odd personally promoted mythology and not on actual sound or even a basic understanding of how speakers work. Otherwise he's right on!
"While others may attempt to help others and offers their experiences as lessons, Bo knows to keep hawking."
Bo is most, blatant but most posts by people in hte "business" here are some mix of these two things, call them what you will.
My understanding is sub woofer speed and accuracy has mostly to do with damping factor, just like with woofers, but perhaps to an even greater extent.
Cone material can make a difference as well, but proper damping in any case is probably the key.
I have seen at least one well regarded sub maker pitch their proprietary application of what seems to be basic negative feedback applied in the sub's built in amplifier as well.
These few things along of course with overall build quality and design probably would account for a lot of subwoofer characteristics typically described as "speed" I suspect.
Audio is about the best sound quality. For subwoofer it is the same story. What gives the best endresults.
Many of my clients in the past with Rel subwoofers bought a granite plate for their subwoofer. It makes a big difference. But still a faster response gives more freedom in use.
After I tested the subwoofer to higher freq. response ( 120-140hz) I got an even better endresult. I got this information from a client. He read an article about Audyssey.
To use a subwoofer this high only can be used when you have a subwoofer with a fast response.
Many slower subwoofers you cannot use that far. You will loose the authority.The endresults are lower.
Against Nordost? This is a product what has the gutts to be different. It is still a nice product. I owned it and I sold it a lot. Why I would be against it.
I prefer brands which are more complete in my opinion. That does not make it a bad product. It is a good products with is different. I like those brands who are different!!
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