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Definative Subwoofer

post #1 of 10
2/8/09 at 4:12pm
Thread Starter 
I have a Definative Technology Reference 1 subwoofer in my home theatre room upstairs that does not seem to produce good bass. My room is 14' X 19' The two side walls are not insulated becuase they both lead to bedrooms. Could these type of walls with no insulation have a negative effect on the bass? My floor is the engineered PERGO flooring. Also the bass is really good in downstairs living room.

Thanks for any help
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post #2 of 10
2/8/09 at 8:09pm

Re: Definative Subwoofer

Have you plotted the frequency response of your sub? Have you tried different locations in the room? It could be anthing from a null in your seating location to a bad sub. The wall and floor material will have very little impact on your sub. It is mostly location, room shape and size.

-Robert
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post #3 of 10
2/9/09 at 5:11pm
Thread Starter 

Re: Definative Subwoofer

Quote:
Originally Posted by Robert_J
Have you plotted the frequency response of your sub? Have you tried different locations in the room? It could be anthing from a null in your seating location to a bad sub. The wall and floor material will have very little impact on your sub. It is mostly location, room shape and size.

-Robert

Robert,

Thanks for your reply! How do you plot the frequency response of sub? Also can too much furniture in a room have an effect on bass response?
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post #4 of 10
2/9/09 at 6:24pm
Thread Starter 

Re: Definative Subwoofer

There is alot of furniture in this room as you can see in the pictures. That big peice of furniture the TV is in from Ethan Allen is about 100" X 90" and takes up most of the back wall. Some day that thing will have to go because I cant fit anything bigger than a 36" screen in it.


BellSouth - Error Message

BellSouth - Error Message

Does too much furniture cause a problem with bass? As you can see there is not alot of places to try the sub out. Also I dont know how to plot the frequency response of the sub.

Thanks!
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post #5 of 10
2/9/09 at 10:42pm

Re: Definative Subwoofer

Plotting your frequency response is simple. All you need is an SPL meter (every serious home theater guy should have one), MS Excel and some test tones (free).
1. Download the PEQ spreadsheet.
2. Download a test tone generator (dozens of free ones floating around the net) and create a disc of sine waves that match the frequencies on the spreadsheet.
3. Mount the SPL meter on a tripod where it is pointing up at a 45 degree angle and head high in your favorite seat.
4. Play the 60hz frequency and turn up the volume until the meter reads 75db.
5. Start at the highest frequency (mine was track 1 on the disc) and play it. Write down the value the SPL meter displays. Repeat for each track on the disc you made.
6. Enter the values into the spreadsheet and view the graph. Are there any large peaks or valleys?

If there are large peaks or valleys then the addition of a parametric EQ can easily flatten out the response of the sub. This spreadsheet is designed to mimic the Behringer Feedback Destroyer. Yes it is a piece of pro gear but it has a great 12 band equalizer built into it. After plotting my sub's response I flattened it in the virtual world and just took the settings and applied them to my BFD. I have a flat response down to 17hz now with enough output to shake the entire house.

Too much furniture may have an impact but only if your room is stuffed like a storage unit. Normal furniture amounts should be fine.

-Robert
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post #6 of 10
2/9/09 at 11:47pm

Re: Definative Subwoofer

Quote:
Originally Posted by tnman
I have a Definative Technology Reference 1 subwoofer in my home theatre room upstairs that does not seem to produce good bass. My room is 14' X 19' The two side walls are not insulated becuase they both lead to bedrooms. Could these type of walls with no insulation have a negative effect on the bass? My floor is the engineered PERGO flooring. Also the bass is really good in downstairs living room.

Thanks for any help
Hi John.

When I put "Definative Technology Reference 1" into Google this is what it came up with, the IWSub Reference. Is that correct?

Also, the location of a sub has a huge affect on its performance. Where is *your* sub located in your room?

Next, if your receiver or processor's speaker management system does not have at least the front mains set to "small", the only time the sub will come alive is when a dvd or cable box's .1 (also called the LFE) channel contains something, which is usually only during loud dramatic scenes. And for 2 channel/stereo sound, during music playback from something like a CD or MP3 player or the radio it won't do anything (unless the receiver is configured to where the sub always receives a bass signal all the time, no matter what the other channels are set to).
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post #7 of 10
2/10/09 at 10:59am
Thread Starter 

Re: Definative Subwoofer

Robert thanks for your input on the plotting the frequency response of the sub. I do have a radio shack sound meter and MS excel and wil be giving it a shot this weekend. If the test shows large peaks for valleys, what parametric EQ would I need?

Lance I have the Super Cube Reference with the 1800W amp built in.

Tonight I will post those picture links properly which will show the pictures of my room. The sub is located in the front corner to the right of the entertainment center. I really appreciete your help and look forward to browsing this forum in the future. You guys
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post #8 of 10
2/10/09 at 6:28pm
Thread Starter 

Re: Definative Subwoofer

Here are pictures of my room. Hopefully this will give you and idea of what I am dealing with.

http://216.77.188.54/coDataImages/p/...meTheatre1.jpg

http://216.77.188.54/coDataImages/p/...meTheatre2.jpg
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post #9 of 10
2/12/09 at 3:50pm

Re: Definative Subwoofer

Sorry for the delay!

I checked out the photos and while that room has a rather large opening behind the listening position, the sub is situated in a nice cubbyhole and should be able to provide solid bass from there (I have experience with a similar room at a buddy's house).

Could the sub possibly be damaged? Or maybe, you simply prefer more bass than that particular sub can supply?
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post #10 of 10
2/15/09 at 5:36pm

Re: Definative Subwoofer

Use room acoustics to your advantage. Place the subwoofer in your typical listening position, and then walk around the room until you hear the bass you're hoping for. Then place the sub in that spot where you were just standing -- that's the best spot in the room for your sub.
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