Advice for 4 Infinity Kappa Perfect 10 VQ for home theater

[taso1000]

Hello,

This will be my first attempt at a diy project. I have 4 Infinity Kappa Perfect 10 VQ's that I would like to use in my home theater in the recommended/argued 4 wall midpoint placement. I did some modeling with WinISD and it looks like a 2.8 cubic foot box tuned to 20Hz is almost perfectly flat. I have read on here that a ported enclosure is recommended for home theater for the low frequency effects. I listen to music and watch movies in a 50/50 split. I found Avaserfi's 12" perfect build very informative and if gave me the inspiration to build 4 separate Infinity Kappa Perfect 10 VQ enclosures. Would a sealed configuration have any benefits? I have read where WmAX roughly states that equalization below F3 in a ported enclosure is not possible/recommended. Once the enclosure plans are decided on with all your help I have questions concerning amplifiers and connection to my existing system. Would a pair of EP2500 amplifiers still be recommended?

Now a little about my current configuration. I have Polk Monitor 70's for my front main speakers. I have 4 Polk Monitor 40's for side and rear surrounds. Center channel is a Polk CS2. I have 2 Velodyne DPS-12's sitting on either side of my tv between the tv and the main speakers running off one lfe output with a splitter. With a lot of crawling around on my hands and knees and some trial and error using TruRta, REW and FBQ2496 this subwoofer placement gives me the flattest frequency response with my main speakers. The room is 24' x 16' and 7.5' high with one door opening on the longer right wall 10' from the rear wall. Walls are covered with wood plywood paneling, floor is carpeted and ceiling is covered with compressed paper type, glued on 12" tiles. Receiver is a Denon AVR-5308ci.

I hope this isn't too much information or not enough. I think I've covered everything but most likely I'm wrong. The receiver has 3 lfe outputs. How would you recommend I connect 4 subwoofers? I had better results running the Velodynes mono on the same lfe output. Budget wise I'm frugal/best bang for buck. I can spend the money if I need to. Also are there any satisfactory pre built enclosures? I could assemble my own but if there are acceptable alternatives I'd consider them. But performance from 70Hz to 20Hz or below is number one priority along with even room distribution. Can my FBQ2496 perform high pass filter duties to protect from subharmonics or is the 24 db per octave slope not steep enough? How would the 4 Infinity's compare to my two Velodynes?

Thank you in advance to anyone who can help or find errors in my logic/plan. I would have liked to find a similar post on the 10 VQ but Alex2507 decided to go with the JL subwoofers.

 

[lsiberian]

http://www.drmarksays.com/?p=25

Use the parameters their for the insert you plan to use.

TLS Guy is the expert modeler here so you won't find a better model or make one. He considers stuff you probably wouldn't think about.

Build that design using the 12vq box as your guide for bracing and folding the port.

For placing the subs that will require you to do a crawl test. You'd find the 4 best spots in your room and place a sub in each spot.

For this you will need 4 channels of amps and a DCX 2496 to control them all.

If you want to go used look at QSC amps they are widely used in studios, churches and bands. Many of which close shop pretty often.

If you want knew you'll want to get a pair of behringer EP2500 amps. For your cables go to monoprice.com.

For new parts buy from zzounds.com(price matching B&H photo video prices)

 

[taso1000]

Thank you Isiberian for your reply. I just found Haoleb's post about his, pretty much, step by step build and read it all the way through. I think I bit off more than I can chew. There is no way I can build that intricate of a cabinet. I have skills but none in cabinet making! Do you know of any reasonable cabinet builders or pre built enclosures? I did find some on Parts Express but they are look cheaply built and expensive. I had another idea from another post I found. Is there a program that I can reverse engineer my Velodyne DPS-12 and find a subwoofer for that would match that enclosure? I know WinISD has the speaker as the known entity and you design the box. What about a program that does the opposite? You have a known spec enclosure then try to find the best matching driver? The exterior dimensions are 18.25" deep, 14.5" wide, height in front is 16.25 and slopes up to 18.25 in the back. The slotted port is 13" x 1.25" x 16.25. The material around the port measures 3/4". Maybe I can use a better performing driver now and change the amp? If nothing can be done to improve the Velodyne I guess I'll have to figure something else out. Does any one know how the DPS-12 would compare to Dr. Mark's Infinity Kappa Perfect 10 ported design?

 

[WmAx]

Thank you Isiberian for your reply. I just found Haoleb's post about his, pretty much, step by step build and read it all the way through. I think I bit off more than I can chew. There is no way I can build that intricate of a cabinet. I have skills but none in cabinet making! Do you know of any reasonable cabinet builders or pre built enclosures? I did find some on Parts Express but they are look cheaply built and expensive. I had another idea from another post I found. Is there a program that I can reverse engineer my Velodyne DPS-12 and find a subwoofer for that would match that enclosure? I know WinISD has the speaker as the known entity and you design the box. What about a program that does the opposite? You have a known spec enclosure then try to find the best matching driver? The exterior dimensions are 18.25" deep, 14.5" wide, height in front is 16.25 and slopes up to 18.25 in the back. The slotted port is 13" x 1.25" x 16.25. The material around the port measures 3/4". Maybe I can use a better performing driver now and change the amp? If nothing can be done to improve the Velodyne I guess I'll have to figure something else out. Does any one know how the DPS-12 would compare to Dr. Mark's Infinity Kappa Perfect 10 ported design?

You can greatly simplify cabinet if you are willing to compromise the shape. For example, if you build a relatively narrow cabinet that had a large height, you could build a simple rectangular box with basic bracing and several long ports. The huge port effective area is one of the important issues. Most subs (DIY and commercial) using ports have substantial compression at and around the port tuning frequency, there by greatly reducing the lowest octave output level of the subwoofer.

-Chris

 

[taso1000]

Chris,

Thank you for your input. What diameter tubular port would reduce the compression? If I chose rectangular, would I use the same rectangular port dimensions as Dr. Mark's design? I know that a smaller diameter port will introduce noise and that the bigger you go in diameter the longer it has to be also from playing with WinISD.

As for plan b, I thought about piggy backing an extension on the back of my Velodyne enclosures. If I remember correctly 8 additional inches in length with the same width and height as the enclosure would give me approximately another cubic foot. I don't think I would have enough space for a tubular port. Maybe 4" or 5" max diameter? I'll have to lay it out. I have a feeling the current 13" x 1.25" opening is too small right?

On a side note. Would the DCX2496 replace my FBQ2496? What does it do additionally compared to the FBQ?

I forgot to add: I read Todd Welti's whitepaper on multiple subwoofers. So I put my two subwoofers in the front half of my room in the " 4 Subwoofers at 1/4 of room dimensions" configuration. That made a huge difference! It sounds a little boomy though. If I have the house to myself tomorrow I'll setup TrueRTA and take some frequency response measurements. I knew subwoofers couple when next to each other but not shooting at each other 8 feet apart!

Taso

 

[taso1000]

Dr. Mark's 10" Kappa build.

I've looked all over to see if anyone has built this and I can't find anything. Can anyone point me in the right direction? I'm looking to see what the impression and real world performance would be.

Thank you,

Taso