Home Theater Forum and Systems banner
1 - 20 of 42 Posts

·
Registered
Joined
·
32 Posts
Discussion Starter · #1 ·
Hello all.
I am planning on starting my first DIY build of a subwoofer (something my system is sorely missing right now) I have read countless posts on this website and others and I think I have settled on one of two subs for the build. Those two being either the SDX15 mk II, which obviously isn't out yet nor do we have any time frame for a release, or Stereo Integrity's new HT sub (probably 18" unless there is a good reason to go 15"), which is at least in preorder. So I believe I have decided on SI HT 18. So here is the help I need - shockingly - it is modelling and a few other minor questions.

I have tried to model the HT 18 on my own but I want to make sure I am doing it right. I am attempting to model a 171.89 L box (26" w X 25" H X 24" D) with two passive radiators (most likely 18" from AE unless there is a better option for similar or less cost). The 171.89 L's I calculated is the interior of the box after subtracting the bracing and the volume for the speaker and a guess on the passive radiators volume. The box is double walled with 3/4 mdf on three sides and single on the back. I hope I did the math right but please feel free to check it. I calculated cubic inches then converted to cubic feet then converted to liters so plenty of room for error on my part.

So here are my actual questions

1. Is there any better bang for the buck driver currently available? I know its subjective but I would love to hear opinions.

2. Is there a better option for passive radiators than AE's. Also I have questions about which weight I should get but that probably depends more on the modeling.

3. The modeling. I will happily provide my model attempts, but I think I have to have five posts before I can. Also what info would you need to look at to tell if I did it right. I downloaded the driver's parameters for WINISD from the SI thread. Then I choose the passive radiator box set up and manually input the PA parameters from AE's website, then chose two. I wasn't sure about the weight addition section so I left it blank.

Last question, what amp would be good to power the SI 18 (I was looking at the Behringer ep2500/4000 but it looks like it might have to much power) and which HT 18 setup should I get the Dual 2 Ohm or Dual 4 Ohm.

Thanks for any help you guys can provide. I am 100% sure that I am getting in WAY over my head, but I figure how else do you learn rather than by doing. Also I would love answers to my questions, but what I would love even more about the modelling is someone helping me understand how to do it myself, so If anyone has any questions about what I did ask and I will happily share. Thanks again
 

·
Registered
Joined
·
490 Posts
personally id go with the si subs.second of all as i recently learned.there is no such thing as to much power.there defo is such a thing as not enough.for subs that size those and tc sounds are the only passives.i know of that would work for it.
 

·
Registered
Joined
·
32 Posts
Discussion Starter · #4 ·
Ok here is my first attempt at modeling. the first file is using the PR18-2100, the second is with the PR18-1600 from AE. I wasn't sure if the listed weight of the radiators counts as weight add to the cone or not. Well actually I wasn't sure about a lot of things. :dontknow: Hopefully I uploaded this right and its what you wanted. Oh yeah and thanks for the replies. I am always open to suggestions that anyone may have. I am glad that I have some others agreeing that the HT 18 seems like the current best bang for the buck.
 

Attachments

·
Registered
Joined
·
32 Posts
Discussion Starter · #5 ·
I forgot to ask, do the TC sounds passives work any better than the AE passives? Since the extra cost of the TC sounds PRs over the AE would be the same cost as another HT 18, I can't imagine they would make enough of a difference that it would be more beneficial to use TC sounds rather than just buying another HT-18. Of course I could be very wrong.
 

·
Registered
Joined
·
32 Posts
Discussion Starter · #7 ·
So does everything else look right? Does the box size look right as in a good performer? Is there anything else I can do to improve performance. Don't get me wrong, it looks to me like it is performing well just want to know if there is anything else to do to tweak it a little more. Is there a reason to choose the 2100 PRs over the 1600 PRs? Their respective graphs look pretty close to my untrained eye.

Also any input on the amplifier? I am leaning towards the philosophy that there is no such thing as too much, however I know that is not always true.

Thanks again for looking at it and sorry for all the questions.
 

·
Premium Member
Joined
·
19,397 Posts
For the 6 cu.ft. box the 17.4 tuning with the 2100's is best in my opinion which is 111 db at 20 hz with 800 watts and a HPF at 14 hz. To get more output you'd need to go to 9 cu.ft. tuned to 16.5 hz with the 1800's with the same power and HPF.


Also any input on the amplifier? I am leaning towards the philosophy that there is no such thing as too much

Only when used responsibly and knowing the limits of your specific design. Burn a coil or do mechanical damage to a driver and you'll lean back the other way.

Power wise a 1000 watt amp would suffice. You can try this without a HPF and see how it goes. If you do get some bottoming out of the sub on movies then you'll need a Mini DSP or a Behringer MIC2200.

Text Line Technology Parallel Font
 

·
Registered
Joined
·
32 Posts
Discussion Starter · #9 ·
Ah ha. I see now. The high pass filter eliminates the concern of cone excursion below 20 hz and the higher I push the wattage the more concern cone excursion would be for the driver at even higher frequencies resulting in a filter needing to be set even higher. I assume the reduction in cone excursion of the driver is also why you like the heavier PRs as well.
I completely forgot about that graph. I hope I am correct in my analysis because I actually feel like I might be learning a little something. Thanks Mike for all your help in this. Question, if I use the heavier passives, It looks like cone excursion is kept in check, thus I likely wouldn't need the high pass filter like you said right or do you usually need a high pass filter?

So anybody have any leads on some decent quality 1000w or less amps? I'd love to read about some.
 

·
Premium Member
Joined
·
19,397 Posts
Ah ha. I see now. The high pass filter eliminates the concern of cone excursion below 20 hz and the higher I push the wattage the more concern cone excursion would be for the driver at even higher frequencies resulting in a filter needing to be set even higher.
Correct.

I assume the reduction in cone excursion of the driver is also why you like the heavier PRs as well.
The heavier PR's lower the tuning frequency and the driver reaches Xmax at a lower frequency as well. Without a HPF the driver reaches Xmax under 14 hz, which is at a point where you may not need a HPF, depending on how hard you push the sub. That's the reason I suggested going without a HPF first, no sense buying something you may not need.
 

·
Registered
Joined
·
32 Posts
Discussion Starter · #12 ·
Thanks for the tip on the amp. I will take a look at it. You guys were great, thanks for all the help. One last question about the PRs. Can I not just add 500 grams of weight to the PR-1600s to make them PR-2100s? Seems silly to pay an extra $60 for 1 kilo of weight. I am sure there is more to it so the answer is no but I was wondering why. When I modeled the PR-1600 with an extra 500 grams added to the cone they modeled almost identically.
 

·
Registered
Joined
·
32 Posts
Discussion Starter · #14 ·
Just wanted to follow up on Mike's suggestion to contact AE about their passives. I was told by AE that the only difference between the 1600 and 2100 is the weight and that they just "glue in" the extra weight into the tube and it can "easily" be done by the customer as well. Seems that this is the way to go for me, now just have to get the wife to agree.
 

·
Registered
Joined
·
32 Posts
Discussion Starter · #15 ·
So now I am wondering if maybe making two sealed 18" subs might be a better bang for the buck than building one sub with passives (two passives cost the same as another 18"). Anybody have any thoughts on this? Is there a way to model more than one sub in winisd? I know you can choose two drivers, but I assumed that was two drivers in the same sealed cabinet. Thanks for any help.
 

·
Registered
Joined
·
490 Posts
2 is for the same sealed cab.they would model exactly the same.having 2 would defo be better.they would smooth out room nodes.and give you more db.
 

·
Registered
Joined
·
32 Posts
Discussion Starter · #17 ·
That was my thinking as well. In my models I have the passive box around 111db at 20 hz and the sealed box around 106db at 20hz. So if I had two subs both modeling at 106db then I believe the percieved output would be 109db (I think that is right if my math holds and my googling skills)

I imagine the benefit of having two subs reducing nodes would likely outweigh the loss in decibels. Any opinion on this? My modeling is right at 600 watts of power since I read ricci's preliminary review discussing that 600w may really be the limit for this speaker. Now I am thinking that the NU3000 with an rms of 550 at 4 ohms per channel might be the way to go for an amp. That is of course assuming the 600 watt limit for the sub is rms and not peak. I'm not sure on that, if it is peak then I might need to think about a smaller amp.
 

·
Registered
Joined
·
490 Posts
the multiple subs would be better than a single.you will get more even bass dispersion.which will eliminate hot spots in the room.2x18 inch subs with 550 watts each will have some massive output.
 

·
Registered
Joined
·
32 Posts
Discussion Starter · #19 ·
So I bought an amp last night. Got, what I believe to be, a great deal on an EP1500 on craigslist. Paid $100 for it and was able to test it first. I now have the wife's approval for two subs. I was thinking of running each sub on one channel at two ohms. The EP1500 supposedly puts out 700 watts at two ohms. I would purchase the HT 18 D4 and wire each in parallel and connect one sub to each channel of the amp. Does this sound reasonable and/or correct?

I have modeled the HT 18 in a 4.25 net cubic foot sealed enclosure with 700 watts and it seems to be a solid performer even with that small of an enclosure. I have uploaded my files in case anybody would be so kind as to check my work and let me know if they think there are some modifications that I should make.
 

Attachments

·
Registered
Joined
·
490 Posts
i just opened your file it looks good.it will go down low without need of a hpf.to get the really low end grunt it would need some eq.it is -10db at 20hz.
 
1 - 20 of 42 Posts
Top