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Discussion Starter · #1 ·
Would it be a wise to tune your sub to about 10 hz, but have you hpf set at 15 hz to help with driver over excursion?

The reason I ask is, to acheive about a 10-13 db increase at 10 hz that is what I would have to do.
 

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Hi there

On my 13.5hz tune subs I get a natural 4db increase between 10 and 16hz. I am not running a hpf and probably wont need to unless I really need to give it some welly. On my simulation running a hpf at 12hz I still get 100db at 10hz for one sub. If I increase this to 15hz which is higher than my tune of 13.5hz this lowers to 93db at 10hz so you will only loose more at 10hz if you add a hpf. It also depends on how your excursion is at 10hz and that depends on your simulation within Winisd. For example something like the 18" maelstrom in a 12 cu ft box tuned to 10hz will give you 108db at 10hz. That has an input of 1000 watts and max excursion never goes over 27mm. No hpf is needed for this but you will need to add room gain for this. I would guess you will see a lift between 10 and 15hz like mine but you will loose a fair amount of output against a higher tune.

Personally that wouldn't bother me as the levels I listen to give me alot of bass. Any more then the house would fall down.

The choice is yours but I would not tune personally as low as 10hz.

cheers

Graham
 

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Would it be a wise to tune your sub to about 10 hz, but have you hpf set at 15 hz to help with driver over excursion?

The reason I ask is, to acheive about a 10-13 db increase at 10 hz that is what I would have to do.
That doesn't sound right. What sub, box size and amp?
 

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Mike,

I didn't really understand what was being said :scratch: as I am sure that would be impossible as the simulation I did in winisd would just further decrease power at 10hz if you ran with a higher hpf than tune.

cheers

Graham
 

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I would also query as to why the OP feels the need to focus output at 10hz. If tuning to 10hz better suits the overall model, then fine use it, but aiming for high output at 10hz is not something I personally would really focus on, there just isnt enough content out there, and we cant hear anything below 20hz anyway.

Is there a particular reasoning behind that?

Also,a 15hz HPF will effectively prevent the 10hz material getting through at any meaningful level, to the 10hz tune should in essence be obsolete.

I would ask the same question Mike has.
 

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Discussion Starter · #6 ·
I was modeling 2 mal-x's, 4 pr's with 1880 grams of mass,19 cubic ft encloser, 15 hz tuning, 15hz hpf, with 4000 watts input yeilds me about 97 db @ 10 hz

But with 2 mal-x's, 4 pr's with 1880 grams of mass,35 cubic ft encloser, 12.25 hz tuning,15 hz hpf, with 4000 watts input yeilds me about 105 db @ 10 hz

It just seems there is a lot more to gain down low with a lower tune. Every day seems like they are adding more and more lower content to newer movies. I just don't want to have to build bigger enclosures later to get a lower tune.

I actually have 4 mal-x's, 8-pr's, and about 8000 watts. So losing a couple db at 20-30hz to get max extention really wouldn't hurt.
 

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A 15Hz HP will just about negate any advantage to tuning that low.

I have an IXL 18.2.2 tuned to 11Hz... theoretically it can do 108dB at 10Hz. Problem there is, I have to feed it with all the power it can take to get it to decent volume above 10Hz, which meant I needed a subsonic filter to keep it from bottoming out. So, I picked the Reckhorn B-2 and set the dial as low as it went, 10Hz. With my receiver at reference level, I can barely get 75dB out of it at 10Hz because the Reckhorn doesn't start the slope at 10Hz... it's more like 13-14Hz where it starts really rolling off.

With a setup like yours, the first thing I'd try is no highpassing at all. You may not need it. I had the IXL like that for a while before I realized I needed the Reckhorn to save the woofer from my abuse... big difference below 15Hz. That said, it takes a lot of volume below that point to get the content so you know it's there... all mine does at 75dB is rattle stuff. I can't hear it, I can't feel it. Once you get down this low, infinite baffle starts making more sense.

But that's just my two cents at way too early in the morning ;)
 

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There's defo something wrong there. I have just modelled a SINGLE 18" maelstrom tuned to 13hz in a 19 cu ft ported box with 1 8" port and 2000 watts with a second order hpf at 14hz and I am getting 105db at 10hz. Two of those would give 108db at 10hz plus room gain which would be more than what you have with the PR's.

Like I said I have tuned my FI Q18's low because I listen to music which plays very low and I don't want to miss out on anything. Yes the compremise is upper bass but to be honest I don't reckon I am missing out much of that. This is comparing to my dual 18 (high QTC) sealed sub which had great upper bass. I find my low tuned subs to be really clean and sound awesome for gunshots and explosions etc....

I was watching black hawk down last night and found myself turning it down from -30db to -35db on the onkyo because the guns sounded like they are in the living room and it may upset the neigbour especially as it was 11pm last night.

Mike will have to step in and double check on your simulation with PR's as I have never done that before.

One more thing with a 18hz tune ported box you would be giving up 5db at 20hz but the lower tuned ported sub would come into it's own 16hz and downwards. The 18hz tuned sub would be down 11db at 10hz. Just gives you an idea or two.

cheers

Graham
 

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I was modeling 2 mal-x's, 4 pr's with 1880 grams of mass,19 cubic ft encloser, 15 hz tuning, 15hz hpf, with 4000 watts input yeilds me about 97 db @ 10 hz

But with 2 mal-x's, 4 pr's with 1880 grams of mass,35 cubic ft encloser, 12.25 hz tuning,15 hz hpf, with 4000 watts input yeilds me about 105 db @ 10 hz

It just seems there is a lot more to gain down low with a lower tune. Every day seems like they are adding more and more lower content to newer movies. I just don't want to have to build bigger enclosures later to get a lower tune.

I actually have 4 mal-x's, 8-pr's, and about 8000 watts. So losing a couple db at 20-30hz to get max extention really wouldn't hurt.
What PR's are you using?

Generally tuning below Fs results in a loss of headroom above Fs. So it's a tradeoff between extension and headroom. I suggest most people stick to headroom especially on a first build.

I'd also suggest 4 boxes rather than 2. It will make life a bit simpler and easily even out the room modes. Are these first Generation or 2nd Generation?
 

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Discussion Starter · #11 ·
What PR's are you using?

Generally tuning below Fs results in a loss of headroom above Fs. So it's a tradeoff between extension and headroom. I suggest most people stick to headroom especially on a first build.

I'd also suggest 4 boxes rather than 2. It will make life a bit simpler and easily even out the room modes. Are these first Generation or 2nd Generation?

1. Im using exodus 18 pr's
2. I know 4 boxes will give me a better overall response, I just don't have the floor space
 

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Discussion Starter · #12 ·
A 15Hz HP will just about negate any advantage to tuning that low.

I have an IXL 18.2.2 tuned to 11Hz... theoretically it can do 108dB at 10Hz. Problem there is, I have to feed it with all the power it can take to get it to decent volume above 10Hz, which meant I needed a subsonic filter to keep it from bottoming out. So, I picked the Reckhorn B-2 and set the dial as low as it went, 10Hz. With my receiver at reference level, I can barely get 75dB out of it at 10Hz because the Reckhorn doesn't start the slope at 10Hz... it's more like 13-14Hz where it starts really rolling off.

With a setup like yours, the first thing I'd try is no highpassing at all. You may not need it. I had the IXL like that for a while before I realized I needed the Reckhorn to save the woofer from my abuse... big difference below 15Hz. That said, it takes a lot of volume below that point to get the content so you know it's there... all mine does at 75dB is rattle stuff. I can't hear it, I can't feel it. Once you get down this low, infinite baffle starts making more sense.

But that's just my two cents at way too early in the morning ;)
My orig plan was IB for my 2 car garage cause it had no room overhead. But my cash fell short and my wife and I decided putting the home theater in the family room was a better idea since we didnt have the money to convert the garage to a home theater. So I purchased the 4 mal-x's & 8 pr's for that build. Then once I explain to my wife how big the surround speakers were going to be she no longer wanted the system in the family room. She was expecting them to be the size of bose speakers. lol
So now i'm back in the garage but stuck with the mal-x's.
 

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I was modeling 2 mal-x's, 4 pr's with 1880 grams of mass,19 cubic ft encloser, 15 hz tuning, 15hz hpf, with 4000 watts input yeilds me about 97 db @ 10 hz

But with 2 mal-x's, 4 pr's with 1880 grams of mass,35 cubic ft encloser, 12.25 hz tuning,15 hz hpf, with 4000 watts input yeilds me about 105 db @ 10 hz

It just seems there is a lot more to gain down low with a lower tune. Every day seems like they are adding more and more lower content to newer movies. I just don't want to have to build bigger enclosures later to get a lower tune.

I actually have 4 mal-x's, 8-pr's, and about 8000 watts. So losing a couple db at 20-30hz to get max extention really wouldn't hurt.
If you were modeling with WinISD could you post the project file?
 

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Fill won't make a noticeable improvement in SPL. I looked up the specs on the PR. You have too much weight added to them. According to the website 1400 grams is maximum. That changes everything. With 1400 grams to each PR it would take 28 cu.ft for a 14.9 hz tuning. That's with 4000 watts and a HPF at 16 hz.
 

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Discussion Starter · #19 ·
The owners manual for the pr's on diycable's website states that the max is 1884. 16 steel disc at 96 grams each, plus 48 grams for the bolt to hold the disc, plus 300 grams for the cone, suspenion,etc.etc.,

16 x 96 + 48 + 300=1884
 

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The website says "Mass Kit includes fourteen 100g steel washers". Anyway, the 300 grams for the cone and 48 grams for the bolt is already figured into the parameters and gives the base PR a Fs of 20 hz so you don't add that in your modeling. It would be best you verify the maximum weight you can add from Kevin.
 
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