Hi,
I can get this subwoofer locally at a very good price (don't recommend any other model as in my country we don't have many available) thus I would like to know how well can the 18sound 18LW1400 perform for subwoofer duty, considering this:
-. I have a very small room, maybe 8 or 9 square meters.
-. Use will be for HT
-. Listening levels will be between 85db and 90db (maybe even less)
-. Have DSP capability
-. The idea is to build 4x subwoofers like this
So, taking advantage of the huge area of this SW, the great sensitivity and power handling and kind of poor XMAX, I though:
-. Use 2 drivers per box, connected in parallel (4ohm)
-. sealed box around 50 liters (for the 2 drivers)
-. 500w amp
-. Apply some Linkwitz Transform + HP around 10hz + (-)12db gain across al the spectrum (I don't need 120db@100hz)
With all that, I do have some good performance according to WinISD. I do hit XMAX at around 200W but I am already above 100db@20hz! Also, I would assume that 8x 18" will pressurize my room at a whole other level.
I understand that according to WinISD I will need a TON of power (above 2kW) but if I consider the huge room gain I might get in my room then I can use a higher fp in the LT and reduce the power needed to get similar performance, or maybe get a bigger sealed box of around 80-90 liters.
So, are these assumptions correct? I uploaded some pictures comparing this simulated driver (in red) vs a dual SBAcoustics 10" SW26DBAC76-3-DV in a small sealed box (in blue)
Cheers
I can get this subwoofer locally at a very good price (don't recommend any other model as in my country we don't have many available) thus I would like to know how well can the 18sound 18LW1400 perform for subwoofer duty, considering this:
-. I have a very small room, maybe 8 or 9 square meters.
-. Use will be for HT
-. Listening levels will be between 85db and 90db (maybe even less)
-. Have DSP capability
-. The idea is to build 4x subwoofers like this
So, taking advantage of the huge area of this SW, the great sensitivity and power handling and kind of poor XMAX, I though:
-. Use 2 drivers per box, connected in parallel (4ohm)
-. sealed box around 50 liters (for the 2 drivers)
-. 500w amp
-. Apply some Linkwitz Transform + HP around 10hz + (-)12db gain across al the spectrum (I don't need 120db@100hz)
With all that, I do have some good performance according to WinISD. I do hit XMAX at around 200W but I am already above 100db@20hz! Also, I would assume that 8x 18" will pressurize my room at a whole other level.
I understand that according to WinISD I will need a TON of power (above 2kW) but if I consider the huge room gain I might get in my room then I can use a higher fp in the LT and reduce the power needed to get similar performance, or maybe get a bigger sealed box of around 80-90 liters.
So, are these assumptions correct? I uploaded some pictures comparing this simulated driver (in red) vs a dual SBAcoustics 10" SW26DBAC76-3-DV in a small sealed box (in blue)
Cheers
Attachments
One box with one 18" (plus Linkwitz transform, with 1000W amp) is more than enough. Tested in 24 square meters room.
Yes, quite small by my local standards and right at the size when I was a teen with two 15"/30 W/~62 Hz Fb, which with no recordings below ~60 Hz generated plenty of live bandstand pressure, so 20 Hz with room gain beginning around 344/2/~2.92 m = ~59 Hz there should be plenty of 20 Hz room gain if fairly solidly constructed, ability to be sealed off somewhat to make those dinosaur stomps feel like it's 'tap dancing' on your chest!
25 L/driver = ~1.17 Qtc, so presume this isn't too high for LT frequency shaping, especially since there may be a lot of room gain to add to the 100 dB + 10log(4) = ~106 dB/20 Hz.
Enclosure volume for Qtc=0.7.
For 18sound 18LW1400 it is 55.5 litres, plus 6.5 litres volume occupied by the driver, so it makes total of 62 litres internal box volume.
I have built about a dozen sealed 18s and ended up with a Q of 0.5 as being the best sounding to my ears.
Yes, I concur Qtc=0.5 is the best sounding. But it is a compromise - enclosure volume vs Qtc. Qtc=0.7 is a good compromise.
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Thanks for the answers... So if I understand correctly from your replies, this is not a "bad" idea, meaning it is feasible to get good SW for HT use performance from the 18 Sound 18LW1400.
Still, with a single woofer and 65 liters, I am excursion limited to 100W -without considering room gain and using a LT filter-
Also to consider, the room is small, 4 concrete walls, 1 small window and 1 door which probably be closed.
Still, with a single woofer and 65 liters, I am excursion limited to 100W -without considering room gain and using a LT filter-
Also to consider, the room is small, 4 concrete walls, 1 small window and 1 door which probably be closed.
Yes, I am aware... that's why I use several SW to smooth the response and each of them with DSP capabilities to smooth the response and manage the room modes.
4 x18” in a room that small with playback levels in the 85 to 90 DB range is serious overkill and what about the size of the boxes in such a small space. Having multiple subs is a good idea but you can also downsize each sub to make them easier to place as well as cheaper to build. 4x10” would be overkill in your room for the playback level you are proposing. A concrete room with few openings will have serious room gain and room modes, so with 4 subs you can expect a big boost in overall efficiency. It’s your money of course but larger drivers will not necessarily give you better bass. You may be able to save some costs and still have killer bass by not over sizing to such an extent. The money saved could find a home improving something else in your signal chain.
The size of the boxes is no problem, as the whole room is only for watching movies and a 50/70 liter box does not look that big tucked in a corner.
My other alternative to the 4x 18sound are 6x SBAcoustics 10" SW26DBAC76-3-DV (I already have them) which is a 10" subwoofer "hi fi" driver with lower sensitivity and highish xmax... do you think this would be enough for a good bass performance?
I always thought that if my listening levels are between 75 and 80db, the sub bass should be over 100db to match it, that's why I thought of the 18s.
Don’t forget that in a room that is only 9sqm you will get room gain starting at a higher frequency than in a large space and also with the walls and floor concrete there is little loss, making higher levels of room gain and also higher Q room modes. If you average the room modes using multiple subs the result approaches an overall higher SPL output. You really won’t know how much power and displacement you need until you try it. I suggest you get hold of a good quality 12inch sub and test it’s capabilities in your room. When properly placed a single 12 in such a small room will play surprisingly loud. Loud is a subjective term and it is your preferences that determine what is loud enough. So getting some sort of reference before going big time on 4 subs might give you the perspective to answer the question of size yourself for your own personal preferences. That is really what matters to your long term happiness with your chosen subs.
In my own case I have 2 15” DIY sealed subs in 3cu.ft boxes with 8mm Xmas and eq’d with a pole shifter circuit. I drive them with a Crown CDI1000 pro amp. I mostly play music. However playing some heavy bass tracks from movie soundtracks it is difficult for me to get the -10db LED to light on the amp. This would be 27w into 8 ohms x2 subs. To me the bass is extremely loud at this level in my 30sqm room. Louder than I would ever play music. Concert level loud for something like Rush or Led Zeppelin. I would never guess that such low power levels were required to produce loud bass. Most pro amps have these level indicator LEDs. I’ve had these subs for 20 yrs. I would like to replace them soon and am shooting for 4 smaller 12 or 10” subs. After moving those big heavy boxes for 20 years I’m ready for something smaller and lighter.
In my own case I have 2 15” DIY sealed subs in 3cu.ft boxes with 8mm Xmas and eq’d with a pole shifter circuit. I drive them with a Crown CDI1000 pro amp. I mostly play music. However playing some heavy bass tracks from movie soundtracks it is difficult for me to get the -10db LED to light on the amp. This would be 27w into 8 ohms x2 subs. To me the bass is extremely loud at this level in my 30sqm room. Louder than I would ever play music. Concert level loud for something like Rush or Led Zeppelin. I would never guess that such low power levels were required to produce loud bass. Most pro amps have these level indicator LEDs. I’ve had these subs for 20 yrs. I would like to replace them soon and am shooting for 4 smaller 12 or 10” subs. After moving those big heavy boxes for 20 years I’m ready for something smaller and lighter.
Four 18s every time. Little 10" drivers really are not subwoofers - picture the size of orchestral instruments designed to produce low frequencies. A pair of 21s could be more cost-effective depending upon what grade of drivers you are looking at, but the box size becomes about 120l. A huge cone area hardly moving is usually going to sound better than a small one flapping around at or beyond Xmax. If you have the space and the money, the utterly effortless nature and huge dynamic overhead of big cones in sealed boxes and big amps is definitely the way to go and will not disappoint. I went sealed on my PA years ago (6 x 18", 6 x 1.5kW amps/4 x 21", 4 x 3kW amps) and find ported and horn-loaded systems to be very difficult on my ears now due mainly to their poor transient response and long decay time...
Move a Lot of Air - Gently.
I agree there is no replacement for displacement when you are talking a PA setup that needs to produce hi SPL for long periods in large rooms. The OP has a 9sqm room! I don’t think he will be displacement limited with 4 X10 or 12” sealed boxes properly placed in the room. I have 2 15” drivers in sealed boxes and I am only using maybe 30w at very loud levels in a 30sqm room. What I urged the OP to do is to get a reference point using a single sub. I personally could not justify the space and cost of 4 good quality 18” drivers, 4 big amps and the space for 4 large sealed boxes given that I find 2x15” is overkill for my needs. I got the CDI1000 new in the box from the owner of a chain of stores. It was surplus to their needs and I paid 300$ for it. It was only then that I realized how little power I was sending to the subs. 100w/ch would be plenty for my needs.