2 subs where do i go next

[spudbudy]

hello everyone after the extremely hard time that I had getting the sound card setup right and working correctly. hopefully this is right I have 2 subs different sizes and after trying to move them around the room and change the crossover and phases on both of them this is what I got any ideas would be helpful

[brucek]

Can you tell us what two different subs you have?

brucek

[Wayne A. Pflughaupt]

Ditto what brucek said.

spudbudy wrote:

hello everyone after the extremely hard time that I had getting the sound card setup right and working correctly. hopefully this is right I have 2 subs different sizes and after trying to move them around the room and change the crossover and phases on both of them this is what I got any ideas would be helpful

Only one graph for all that moving around and phase adjustment? Or is this the one you felt was best?

Regards,
Wayne

[spudbudy]

hello gang, yes only 1 chart as I fell it looked the best but, I have others to post if needed. I have 2 velodyne subs the small/old 1 is model VA8100X and the 2nd and larger sub is model DLS5000R. both sub now have Y splitters on them as I noticed that it did make quite a difference in db levels. the main/large sub phase is set to 270 and the small/old one is set to 180. crossover is set to 80hz in my AVR both sub xover set to direct. room placement main is @ 7 1/2 from end of room on one side and the smaller one is 6 feet from the opposite end of the room on the opposite side of the room from the main sub. I tried the main sub first, then the small one by themselves next turned both on and thats what I got.

[brucek]

I have 2 velodyne subs the small/old 1 is model VA8100X and the 2nd and larger sub is model DLS5000R.

There's a tremendous temptation when we move up the food chain to a large 15" monster like the DLS5000R, to want to still use out original smaller subwoofer. This practice is never a good decision, but everyone usually goes through it.

The VA8 is a small 100 watt 8" subwoofer that has a response that's down -3dB by the time it hits 35Hz.

The DLS is a 600 watt 15" sub that has a response that extends to 23Hz.

What happens when we combine these two is that the response of the larger sub dumbs down to the response of the challenged sub.

This is a result of the SPL levels in the room adding for shared frequencies. As an example, both these subs are capable of producing 50Hz quite nicely, and when played in concert, the output is additive and as a result you will adjust their level to achieve a certain overall SPL level. What happens at 25Hz? Only one of the two subs is capable of producing that frequency, yet it has trouble doing so since you've turned it down to accomodate the challenged sub being turned on.

My advice. Use the single 15" and see what you can get out of it.... If you require more SPL level, add a sub with similar response

brucek

[spudbudy]

brucek thank you for your insight. I agree with you about the 2 different subs. thats the main reason that I moved up to the dls model the small one just couldn't cut it in my room addition. the DLS was the sub that was recommended to me. I understand what you are saying so I will be taking your advice and just run the DLS and unhook the small one. After rerunning some more measurements with the DLS I will post the results and once again look to the experts on this forum to set me straight. thanks again

[yourgrandma]

A question of arelated nature, if I may momentarily jack the thread. What would the recomendation be if one wanted to add a sub for the rear chnnels and it was smaller than the main sub? Also, the fronts have built in subs that can play quite low, but not at the same volume as the main sub, are they inherantly dragging the big sub down, or can the system be tuned to take advantage of the full range capabilities of the towers without hurting overall responce(which i believe is a function of phasing, but the sub onlay has a 0/180 switch, and obviouslty the speakers are not adjustable.

Again, sorry to jack, but i feel its a good question to address.

[brucek]

To me, all the questions about adding extra subs can be boiled down to a single truth. If the subs will be sharing signals that are at the same frequencies, they better have matched responses or there will be a problem.

I don't really understand the rear channel sub. If the rear channels are set to 'small', all the low frequency information will be directed to the main subwoofer. I suppose if the rear channel speakers were challenged and couldn't extend their signal down to the crossover, a small sub that reached to the crossover could be added with a speaker level connection.

Besides the obvious fixed location problems with built-in tower subs, there will be an extension limitation to your system if the standalone sub and the built in subs don't have identical bandwidth capabilities. One of the biggest problems with built-in tower subs is getting the user to run them in 'small' mode when they add a large standalone sub to the system.

brucek

[spudbudy]

ok here there are. since I dropped the 2nd small sub from my lineup this is what I'm left with your thought's please. one is on the left side of the room and the other is on the right.I will be looking to purchase a BFD for doing my adjustments which location will give me better results? Thanks

[Wayne A. Pflughaupt]

The top graph looks much better. A bit more extension, and it will be easy to equalize.

Hard to believe that a 15” sub can’t get much below 30 Hz...

Regards,
Wayne

[spudbudy]

thanks I will move it to that location. I do have a question about which way to face the RS SPL? I have seen posted that it should point up toward the ceiling, also horizontal this changes the graph so I'm left to wonder which is more correct. I did this in the daytime so the background is noisy with traffic and trains going by.this sub should goto 23hz or so it says. could just be the RS SPL isn't sensitive enough to pick it up?

[brucek]

this sub should goto 23hz or so it says. could just be the RS SPL isn't sensitive enough to pick it up?

Well, 23Hz is about where the first graph is 3dB down...... looks about right...

brucek