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Discussion Starter #1
Due to WAF I am restricted in size to a box that can only support a 12" sub.

I already own an M5 IXL 12.2 and an Rlp D4. Considering this is for the family room where it will be used 80% of the time for TV, I'd like to build an inconspicuous enclosure for the corner of my room. The other driver will end up being a 100% music sub for my office.

Receiver will be either an Onkyo 876 or Denon 3310 so I will have Audyssey and also would have no problems adding a BFD. The receiver will be in the basement controlled by home automation software and the sub upstairs. In hindsight I screwed up the wiring and didn't run speaker leads for the sub so I will be restricted to a plate amplifier.

I have used both of these drivers in my vehicles, but now with a new house I am changing my focus to where I really spend my time. In cars both Mark and Mike's recommendations on box sizes seem to be pretty spot on, so I would assume this to be the case in Home audio as well but wanted to ask as searching the forum brings up tons of information on 15's and larger (for obvious reasons) and not much on 12's.

Currently leaning towards 2.5cuft tuned around 15hz, but that sounds like I am leaving out the first L in LLT. This leaves me with three current things that I am pondering before I start building.
Should I be making the box larger?
Which driver do I want to use (realizing that the coils on the IXL make it more plate amp friendly)?
What plate amp (super bummed I missed the PE 1000w when it was on sale for $350)?

*process is just starting, will update the thread as I go along with the build. My target is to start after the weather here in MN makes it so that I can't spend time outside. I have to build a cabinet for my bathroom and will be making the enclosure at the same time. Thread will include pics and details as this starts to happen--in the interim please comment away :yes:
 

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2.5ft tuned to 15hz will be hard to pull off without having a port that is very long. What about going for a PR'd enclosure? A couple of 15" PR's could be nice with one of those 12's.
 

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Discussion Starter #4
While that is a possibility it would actually be easier for me to hide the sub if it didn't have PR's. "she" wants furniture...

My way around this was to potentially deal with some port noise. At loud levels if I used a 4" aero near tuning there would definitely be some chuffing. With music this shouldn't happen and it will only be effects on movies which we actually rarely watch. This is really a tv setup, but I do hate the compromise. This would still be long nearing 60" but would be do-able and should keep the 1st port resonance above 115Hz.

Am I too hopeful that this would be tolerable?
 

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How about firing the driver down? Then you'd have just the 2 PR's firning opposite directions. You could always qo with black cloth covered grills over them. A 60+" long port which is still underported and takes up almost a half cu ft of volume seems like too big of a compromise to me if you can afford to use the PR's.
 

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Discussion Starter #6
I was going to fire down and port down. That way the sub would just look like a cabinet in the corner. If I did two radiators they'd have to fire out the two directions from the corner which will make them harder to hide.

I have more space than 3cuft, but the footprint has to stay fairly small and the woman wants it to look nice. The large port then fits, but the fact it is under ported is the frustrating part and hard to work around as a 6" in that small of a space would be far from ideal as well.

The basement will get a home theater room with no compromises a year later, but this is for the family room and my argument for better sound is getting a little trumped by her.
 

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Discussion Starter #7 (Edited)
Here are some pics of the to be location. Her goal is for me to build a "cabinet" and have it hide away in the corner like a piece of furniture. I can move the picture, but not the window nor the closet door next to it. My goal of course is to add some lows to the family room.

edit: For sizing purposes I put the Rlp 12" in the corner

 

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To be honest I think you're asking too much from this sub tuning it to 15 hz. With a 18 hz tuning they both have the same output at 15 hz and the higher tuning has a 3 db advantage above that. The port would also be 18 inches shorter. The modeling is with a Dayton 1000 watt amp that has a Hi-Pass filter at 18 hz.

IXL12.JPG
 

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Discussion Starter #9
Was playing around with adding size to the enclosure to shorten the port and noticed that I was a wee bit optimistic. Trying to balance excursion, output, and lfe is always fun. It really makes me want more cone area.
 

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Discussion Starter #11
The addiction has taken hold. There is now no hope for you!
There never was. I spent last Christmas to New Years pulling wires. 8 rooms wired for sound, 5 for tv, and I am just getting started. Pulled enough for analog and digital :jiggy:

Bought the house in December. Very livable, but I am not one to leave things alone. I have to do this on alternating w then my projects
W-downstairs bathroom first, I gutted an re-did but still need to build a sink base cabinet and sink top
Me-whole house audio and family room sub/speakers
W-master bedroom/bath complete gut
Me-home theater in basement. 14'x22' room with no windows, what else could you use it for? With enough sound deadening maybe we'll lock our son in there when he gets older to.
-not sure what she'll have me do after that
 

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Discussion Starter #13
Mike's comment from the Port Length Thread ( http://www.hometheatershack.com/for...ported/12042-port-length-recommendations.html ) has me wondering if I am trying WAY too hard to keep port velocities low. He also chose a 4" port for an IXL in a slightly larger box. Last night I spent a bunch of time playing with 6" port designs and had then leaned towards doing a slot. In a box like this with an application like mine is there a velocity you'd really limit things to? Being a chuffing noise is full spectra I assume frequency independence other than of course the source material has to be at the frequency that would create the flow.

Good points Josh. Now there is the issue of port airspeed and what is an acceptable limit. I've seen recommendations to "keep it under 26 m/s" or "keep it under 30 m/s" and so on. I just finished testing and IXL-12 in 3.5 cu.ft. tuned to 18 hz with a 4 inch flared port. Modeling showed 38 m/s at 18 hz and all I heard was the windows, door, and walls vibrating. I stood beside the port and noticed a lot of air movement in the port but did not hear "chuffing" or any other port noises. It appears that the lower the tuning frequency the higher the airspeed can be, especially for HT subs, where the effect of sub 20 hz frequencies on the room will mask any noise that can potentially come from the port.
 

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Discussion Starter #15
Some preliminary plots, both boxes 3.2cuft and 17.7Hz, 5.3" port (will slot), port resonance 122Hz

RLp -> LP 90Hz LR-4, HP 12.5Hz LR-4, Para EQ 50Hz Q1 -1dB
IXL -> HP Butter-4, 15Hz, LP LR-4 90Hz





I still have more playing to do, but any comments so far?
 

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Discussion Starter #17
I have a Crown ComTech 800 in my closet that I may try to use...even though in this location a plate amp would be easier.

If I use the Crown though I have no HPF at all which means I need some sort of processing. Currently reading through threads and info all over the web trying to determine if the DCX will do everything I need so that I can use it as a crossover and not also need a BFD. Behringer's online manuals/specs really aren't very helpful.
 

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As pointed out, that 3rd order hpf will increase the excursion between 10 & 20 hz, port vel will follow suit in that range. Although you may have a mm or two over xmax to play with.
Since you'll need a hpf anyway, tune closer to 20hz and you can get away with a shorter port and you'll gain useful spl you'll want using only one driver. A slot port looks favorable to me and maintains aesthetics.
 

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Are you crazy?

Your sub has an Fs of 24.6hz and your tuning it to 15hz?

I suggest a 1.472 cuft box tuned to 24.7 hz.

Tuning below your subs Fs is a bad idea IMO. There isn't much below that frequency anyway.

Actually that box will be difficult to pull off. You would need too long of a port unless you plan to limit the amp. Considering the application I don't think you need hi-fidelity so you may be ok. I don't have the T/S parameter for the other driver. So I can't give an opinion of that option.
 
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