Subwoofer Integration

[artto]

I finally got around to measuring the frequency response of my new subwoofers, which as many of you already know, I decided on a quad of Epik Empire. I'm not much of a Home Theater buff so I can only comment from a musical point of view.

At first I was very impressed with the sound but as usual, after you give it some time and additional critical listening to a variety of material I began to realize that this would not be simply plug and play.

The first thing that became apparent was the upper frequency range of the subs. These subs actually have pretty good response extending well up above 120Hz. This created interference with the Khorns so the first thing I did was try to cut out all the "higher" subwoofer frequencies. The Epik Empire's lowest crossover frequency is 40Hz @ 12dB/octave which just didn't do the job. I finally decided to use a Behringer DEQ2496 with its multiple filter types to knock off as much as I could above 40Hz and also for flattening the Empire's response down to 16Hz. The time delay on the Behringer also was handy to get the subs time aligned with the Khorns. Later I also bought a second Behringer DEQ2496 to use on the Belle center speaker to time delay it so it matched up with the Khorn's midrange driver and use the graphic EQ to cutoff everything below 50Hz on the Belle.

I must admit even I'm impressed with the results. The system really sounds absolutely awesome. Even my wife said the same thing. And my niece and her husband, both in the music biz (she trained in opera at DePaul and later switched to audio technology) said it sounds "amazing". It's only another 16 notes or so but it really adds another dimension to anything that has information down there.

I've moved the outside subs a little farther apart than what the original picture shows - probably not noticable in pictures like this anyway, just a few inches.

[artto]

This is the initial frequency response of the subwoofers, no EQ, just their internal crossover set to 40Hz @ 12dB/octave.

[artto]

This is the subwoofer response after EQ with the Behringer DEQ2496

[mustang guy]

Now that's flat response! Great looking setup as well.

Have you tried flaring the right and the left subs out? I did that with my THT's and it vastly improved the overall sound. I have a THT on each side of my center LaScala, and they are flared about 15 degrees out. I did not measure it, but my ears were happier, and there were fewer dead zones afterwards.

I flared them like that, because I was perceiving some cancellation while sitting in the sweet spot. In the future I may corner or wall load them, but as they are, they really do sound fantastic. I had to turn up the gain about 4-6db, though.

[Rdmarsiii]

It makes me wonder how the response would change if they were stacked. I'm running four of the Ultra2 subwoofers, but its only feasible to have one of the pairs stacked.

[joshjp]

artto, im jeleous, i have one Empire, man with 4 i couldnt amagine how they would be, BTW did you get a better frequency responce with the woofers facing towards the listener, or having them facing the other way?

[derrickdj1]

Now I am really curious on where the woofers should face on my Epik, I just face the log end toward the listening area. I may play around with it some more. The Behringer really made a big difference. Thanks for posting artto. Now I want to do measurements. Sometimes you think things are good and someone shows a way to make it better.

[artto]

Have you tried flaring the right and the left subs out? I did that with my THT's and it vastly improved the overall sound. I have a THT on each side of my center LaScala, and they are flared about 15 degrees out. I did not measure it, but my ears were happier, and there were fewer dead zones afterwards.

I flared them like that, because I was perceiving some cancellation while sitting in the sweet spot. In the future I may corner or wall load them, but as they are, they really do sound fantastic. I had to turn up the gain about 4-6db, though.

No, I haven't tried flaring them out although the thought did cross my mind. These are pretty heavy and moving them around on the heavy carpet is quite a task. The Epik Empire have dual opposing drivers. So far, that appears to negate any need for orientating them differently, especially when using four of them horizontally across the 1/4 space plane.The multiple units across the area help overcome and smooth out some of the room mode issues as not all subs are actually producing the same level at the same listening position ~ their relative locations are different so their room interactions are different. I guess you could consider it an expensive way of smoothing the low frequency response ~ albeit with lower distortion and higher output capability []

I was considering a custom made pair of low profile THT that I was going to stand vertically on each side of the Belle but I decided they needed to be too wide to get the response I wanted and projected well beyond the face of the Belle. I didn't want them causing defraction interfering with the sound coming from the Belle midrange and treble. Other orientations and locations would have produced other issues so I decided to go with these.

I might add that I used the NCH Tone Generator to produce sine waves at actual musical note frequencies as opposed to pink or white noise which is why the frequencies are so close together. IMHO 1/3 bands don't tell you much down there. And I'm sure the Radio Shack SPL meter/microphone is rolling off down there so the actual lowest frequency output is probably a little higher than measured. I just got a Dayton calibrated mic but that is also down -2.2dB at 20Hz and I suspect my Oktava MC012 omni are similar. One thing is for sure. I'm going to have to secure a number of things in the room to stop them from vibrating.

[artto]

It makes me wonder how the response would change if they were stacked. I'm running four of the Ultra2 subwoofers, but its only feasible to have one of the pairs stacked.

I was thinking of stacking them, a pair on each side of the Belle. But as I mentioned in the post above I didn't what any defraction interfering with the center speaker as these subs would also extend beyond the face of the Belle although not as obtrusively as the THT subs. Also, consider that placing them horizontally along the 1/4 space plane should provide better reinforcement. Also, I have some issues with my neighbor to the south of me (left side of room) and stacking the subs puts a pair of them above the foundation wall which will most likely allow more low frequencies to project through the upper above grade walls. Although I do like the idea of stacking them because this supposedly helps with projection ~ the sound level doesn't fall off as fast with increasing distance. I'm not sure how much effect that will have in a closed space this size.

[artto]

Now I am really curious on where the woofers should face on my Epik, I just face the log end toward the listening area.

With one of these Epik Empire or Legend it probably makes sense to have the long end toward the listening area regardless of where the sub is located. I didn't do that in my situation because I would end up with drivers facing each other which I would think cause cancellations. I thought about it for a while and decided it would be best to have the all the drivers on one side facing one direction and the ones on the "back" side firing off the wall along the 1/4 space plane. At some point in the future I may experiment more with their placement and orientation but for now I'm very satisfied with the results I'm getting, both measured and listening. And of course, it looks cool too []

[derrickdj1]

Looking cool is what it is all about. Some people say 2 sub will get you 70-80% to Nirvana, so with 4 subs, you should be in HT bliss. If you keep experimenting with the subs, I know of a good hernia doctor[]

[CECAA850]

It IS really amazing what adding the bottom octave or so does for music. To me , it gives the music "weight" which is the best way I can describe it. Before too long (if not already), you'll wonder how you listened to music without them.

[artto]

It IS really amazing what adding the bottom octave or so does for music. To me , it gives the music "weight" which is the best way I can describe it. Before too long (if not already), you'll wonder how you listened to music without them.

Carl, yes I'm quite surprised. What's really surprising is listening to the same music without the mains, subs only. There's not a whole lot coming out the subs but when put together with the mains the sum of the total seems to be greater than the parts. It also seems to improve definition of the midrange, maybe because of the increased contrast. And apparently I'm not the only one who's noticed this effect.

And I couldn't agree more ~ "weight" ~ that's exactly how I'd put it. Obviously there's a lot of music where there's nothing down there, but even on some "lite" jazz recordings I got recently with acoustic bass (Esperanza Spalding and Terri Lyne Carrington) the subs add that certain "weight" to the sound. On Telarc's SACD of Carmina Burana there's some really low stuff down there in the quiet parts that I didn't really notice before.It's almost as if I was "hearing things", and then it stops, and you realize that you really were hearing something down there, even feeling it slightly, it wasn't just noise or something. I can hear the low frequency hall ambience of the lowest organ pedal tones even at very low levels.

So yes, I've already wondered how I did without it them. But then again, the price was right, the timing was right, what I got for the money was right, and the design of these subs integrates well with my setup, not to mention the manufacturer is in my backyard and I could return them risk free, so I decided to try it. I must admit, I don't get impressed by much anymore but this really put the icing on the cake.

Just for the record, my two favorites so far are Peter Gabriel's SACD "Up" and Insane Clown Posse's "Bizzar Bizzar". On "Up", second track "Growing Up" there's a sustained pause towards the end where the synthesizers seem to go down to the center of the earth, and then pull back up again. The sound just pulls together so wonderfully, powerfully with great weight. It reminds me of when I was playing in bands and once in while we'd that kind of sound live, very elusive, hard to achieve, never could figure out why, but it's here consistantly with the subs. And Insane Clown Posse, Holy ***** %$#@ )()(****& ****%$#@!!!!!. The low stuff on there is amazing. ICP I'm sure is not everyone's cup of tea, but personally, I find them kind of funny. The synthesizer work on the low end is quite amazing. My wife hates it. Says everything in the house is rattling upstairs. And on Easter we had family over here. My wife's niece and her husband are in the music biz. She studied opera at DePaul but switched to recording technology halfway through. Apparently when I put on Telarc's 1812 Overture with the real canon shots, everyone up stairs was like "HOLY *****!!!! WHAT THE HELL WAS THAT?!!!" Did a plane crash or something? Sounds like a bomb went off....there it is again, and again!!!!!"

ROTFLMAO [] [Y]

[Quiet_Hollow]

Wow...quite the spread there. PG to ICP? []

Now that you've got some sub-bass headroom..you must try this if you already haven't.

http://archive.org/details/LaunchOfSpaceShuttleEndavourOnMissionSts-123

[ivanhurd]

That seems pretty umm....epic? =^P

[joshjp]

That seems pretty umm....epic? =^P

Yea it does, i might have to try it.[]

[artto]

Wow...quite the spread there. PG to ICP?

Now that you've got some sub-bass headroom..you must try this if you already haven't.

http://archive.org/details/LaunchOfSpaceShuttleEndavourOnMissionSts-123

I'm having trouble downloading the wave file. Anyone else having problems?

[artto]

OK, I guess we can't actually download the file and save it. It looks like it has to stream from their website. []

I finally found the doucmentation for SPL reference and it looks like its about 120dB A weighted. I had this up to about 108 dB. There's a huge amount of midrange energy (crackling sort of sound, much like that of lightening). I hate to say this, but my Khorns are 35 years old and all original. I don't know if they can tolerate the required output without failure. No problem on the subs so far.

[Quiet_Hollow]

On the site, try right-clicking the "wave" link listed in the audio files section, then select "save link as...". It's a big 70 MB .wav file, so it'll take a bit to download. If that doesn't work shoot me an email, and I'll attach you a copy from my end. [H]

That crackling sound are shock waves from the exhaust going supersonic in the nozzles.

Throw a multimeter across the KHorns, check what kind of voltage they're seeing. I'd be willing to bet at 108 dB, it's still less than 10V RMS. []

[artto]

Throw a multimeter across the KHorns, check what kind of voltage they're seeing. I'd be willing to bet at 108 dB, it's still less than 10V RMS.

Yes, but I'm measuring SPL (C weighted) at the listening position which is about 18.5 feet from the Khorn drivers or about 16.5 feet from the K400 mouths. And don't forget my room is pretty well damped. The guy who recorded that (120dB at the viewing site) was using A weighting on the SPL meter instead of C. That's pretty !@#$%^&***#!! LOUD for 3+ miles away!!!! I really don't think a setup like mine can duplicate that sort of effect even in an enclosed space the size of my room. I'd probably need the front and side walls lined top to bottom with K402 horns using the larger EV, JBL or TAD drivers (and probably more subwoofers), which in turn would require a lot more power, and maybe even 240V/200amp service or more ~ to the room, LOL. [:S]