MPTY, but what happens if you move? Are you going to remove the built-in sub and take it with you? AND, one of the ONLY means you have of ridding a room of 1 or more deep cancellations somewhere in the bass frequencies is to MOVE THE SUBWOOFER to find spots where there's little or no cancellation due to room modes. You can't do that with a built-in. Nor can you tell in advance with a built-in whether you have the bass output entering the room at locations that are optimal. I ALWAYS "map" a new room for room modes that cause deep cancellations. That can take DAYS to find all the modes in a room by making measurements in a grid pattern in the room using tones from 16 Hz to 150 Hz. My room for example, will completely eliminate frequencies around 50 Hz in much of the area around the projection screen (which is 8-feet out into the room from the walls behind it due to the 28 foot depth of the room being so large).
In the room I have now there are 3 areas behind the projection screen and 3 areas in the back of the room that have NO cancellation modes beyond 5-6 dB. You can NEVER equalize your way out of a deep cancellation due to a room mode, the cancellation just gets stronger if you try to raise the SPL with EQ. When you can purchase a commercial sub that can be flat to 16 Hz with proper placement for under $1000 Hsu Research (or getting a used one), building a horn that becomes part of the house in a crawl space seems like a lot of torture, for little or no gain aside from the DIY satisfaction. If "tight" musical bass is desired, use a sealed-box subwoofer, OR a ported sub that comes with plugs to block the ports can be turned into a sealed box for music (won't go as deep or as loud as a ported box, but distortion is lower) or remove the port plugs to return to ported box mode (deeper and louder bass with more distortion) for movies. The movie "The Edge of Tomorrow" has a bass effect that goes all the way down to 10 Hz at the beginning of the movie. It starts even before the Village Roadshow logo disappears at the end of the opening credits. So modern movies do have some interesting things in the soundtracks. I have a $2750 sub here now that is in a sealed box and it is "done" with bass around 23-24 Hz, but it has a nice sound with music. A sub-$1000 Hsu Research sub goes down well below 16 Hz in my room even though you cannot HEAR anything below 16 Hz, when the effect in The Edge of Tomorrow goes below 16 Hz, the subwoofer feels like a fan was turned-on in the room... you feel WIND from the subwoofer below 16 Hz in my room. But the $2700 subwoofer cannot do that. There is a LOT to consider when it comes to bass. If you are moving or working in a crawl space, I STRONGLY recommend a Tyvek haz-mat suit from Home depot including shoe covers, hood over your head as part of the haz-mat suit, a face shield and a good mask over your nose and mouth to prevent you from breathing dust in the crawl space. Getting dust from rodent feces in your hair, clothes, and skin is enough to deter most people from crawling under the house without protective covering. Remove the protective gear as you exit the crawl space so you do not drop feces dust or pee dust inside your home. Rodents can carry hanta virus which is VERY nasty and it can lay dormant in feces or feces dust for a LONG time. So if rodent pee or poo alone isn't enough to deter you from "going under" without the protection, at least be concerned for others in your family who might be exposed to a serious health threat if the hanta virus is brought inside your home.
In the room I have now there are 3 areas behind the projection screen and 3 areas in the back of the room that have NO cancellation modes beyond 5-6 dB. You can NEVER equalize your way out of a deep cancellation due to a room mode, the cancellation just gets stronger if you try to raise the SPL with EQ. When you can purchase a commercial sub that can be flat to 16 Hz with proper placement for under $1000 Hsu Research (or getting a used one), building a horn that becomes part of the house in a crawl space seems like a lot of torture, for little or no gain aside from the DIY satisfaction. If "tight" musical bass is desired, use a sealed-box subwoofer, OR a ported sub that comes with plugs to block the ports can be turned into a sealed box for music (won't go as deep or as loud as a ported box, but distortion is lower) or remove the port plugs to return to ported box mode (deeper and louder bass with more distortion) for movies. The movie "The Edge of Tomorrow" has a bass effect that goes all the way down to 10 Hz at the beginning of the movie. It starts even before the Village Roadshow logo disappears at the end of the opening credits. So modern movies do have some interesting things in the soundtracks. I have a $2750 sub here now that is in a sealed box and it is "done" with bass around 23-24 Hz, but it has a nice sound with music. A sub-$1000 Hsu Research sub goes down well below 16 Hz in my room even though you cannot HEAR anything below 16 Hz, when the effect in The Edge of Tomorrow goes below 16 Hz, the subwoofer feels like a fan was turned-on in the room... you feel WIND from the subwoofer below 16 Hz in my room. But the $2700 subwoofer cannot do that. There is a LOT to consider when it comes to bass. If you are moving or working in a crawl space, I STRONGLY recommend a Tyvek haz-mat suit from Home depot including shoe covers, hood over your head as part of the haz-mat suit, a face shield and a good mask over your nose and mouth to prevent you from breathing dust in the crawl space. Getting dust from rodent feces in your hair, clothes, and skin is enough to deter most people from crawling under the house without protective covering. Remove the protective gear as you exit the crawl space so you do not drop feces dust or pee dust inside your home. Rodents can carry hanta virus which is VERY nasty and it can lay dormant in feces or feces dust for a LONG time. So if rodent pee or poo alone isn't enough to deter you from "going under" without the protection, at least be concerned for others in your family who might be exposed to a serious health threat if the hanta virus is brought inside your home.
