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Obsidian Audio 18 Enclosure Assistance


image91

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Thanks for the input sckeeler11!

BassMunky, I honestly wouldn't describe it as cheap sounding at all O_o It's a lot more accurate/musical than I expected for an 18. The low notes are deep & heavy, just the way I like ?

With that being said, I am off to start another topic because:

I was presented with the opportunity to upgrade to an X 15 v.2

So although I really like running a single 18, the X 18 is too far of a stretch in terms of power/current & box space. Going with the X 15 will free up some trunk space (which although not necessary is still nice) & if done right, might very well out-perform the OA-18.

 

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  • 1 month later...

Good day all. Still using the Obsidian 18 for now. Considering another modification to fire the port upward along with the sub. Hoping to take this opportunity to make any other tuning/size adjustments. 

On checking the tuning via the method suggested before, it was determined to be around 29-30 Hz. The problem is, the higher notes are outperforming the lower notes significantly, even with that tuning & crossed at 40 Hz @ 36db slope. Tried running it off a friend's system & the output was a little better, but similar. His system was closer to 1800wrms & had a bit more drive to it though. Only played a similar song shortly for comparison purposes. This led me to believe that it was not the system/current etc. but the box or sub.

For 1200wrms, is the net volume too much @ 5.25 ft^3? Is the port area possibly too small @ 63 in^2? Would tuning any lower make sense @ 29-30Hz? Is it possible that firing port upward instead of back will help?

For someone who prefers higher notes & a "louder" system this would be perfect but i have a strong preference toward lower tones & just want to make sure that nothing is preventing the system from reproducing them optimally. 

Edit: Just found an old post discussing port area & minimums of same. For an 18, minimum port area was around 115 inch^2? O_o i'm currently using half of this? Lol. 

As always, any help would be greatly appreciated, thanks! 

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The main thing you are battling against is just the fact that the OA18 doesn't have a really powerful motor for its cone size (as shown by its high QES).  Because of this you get a raw frequency response like this:

image.png.4aba67ef1e47458589cef94d5b9a65d4.png

Cabin gain is going to boost the low end quite a bit from what shown in that graph, but its not enough.  Unfortunately there really isn't a lot you can do to get more low frequency output.  You could make the box bigger, which would help somewhat, but even increasing it to 8 cu ft isn't going to make a huge difference.  

As far as you port area goes, based on the amount of power you are running the port area you have is more than sufficient.  

If you want to reduce the peak in output you get around 40 Hz you can add a DSP to your system.  A DSP would be an additional cost and they can't make a sub any louder, but they can do a great job of reducing peaks in output, so it would make the lower frequencies sound louder relative to content in the 40 hz region, even though your system overall won't be any louder.  

"Nothing prevents people from knowing the truth more than the belief they already know it."
"Making bass is easy, making music is the hard part."

Builds:

U7qkMTL.jpg  LgPgE9w.jpg  Od2G3u1.jpg  xMyLoO1.jpg  9pAlXUK.jpg

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Just the guy i was hoping to hear from with just the news i was hoping not to hear, lol. Sort of figured this would be the situation in terms of not a lot we can do to increase the low end output. Was just about to plan out another mod to fire upward & cut down the net volume to 4.0 ft^3 using same port area & tuning. Back to a recommended spec basically to see if there would be a difference. From all appearances, that would be somewhat pointless. Only thing i'd maybe gain is a bit more controlled response & some trunk space. Possibly not worth it. Reason i may consider still dropping the net volume is for purpose of sale. A 5.9 ft^3 enclosure will be quicker sold than a 7.0 ft^3 imo.

Even if i reduce the peak, the lower end will remain the same & i was definitely striving for a heavier low end. This is the goal & so, back to the drawing board. Hoping that the x15 will be what i'm looking for. Either that or an attempt at an x12 T-line O_o If not, may have to go back to multiple subs. Was hoping i could turn project Obsidian around but unfortunately it's apparently not suited for my personal preferences.

Thank you very much again bro!

Anyone have any thoughts on the plans moving forward? Will the x15 be a significant upgrade in the 28Hz-34Hz department? x15 in a recommended spec enclosure vs x12 T-line? Or should i go the route of maybe two SA-12s or multiple subs in another series tuned on the low side?

Any input would be greatly appreciated as always!

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Well I wanted to add that part of your problem is a having a large vehicle as cabin gain is not so strong, if you want stronger performance you should get serious about getting it, here are some modeling results for the OA18 5.8@28Hz vs the X15v1 4.25@28Hz both on the same power:

image.jpg

 

So Since the x15 has less cone area there is an output penalty for that, regardless using it will drop the higher bass gain and focus output on the range you are interested in, if you can push more power into the X15 it could certainly overtake the OA18, probably 3-4 dB if you really push a lot of power into it, I guess it would be a worthwhile improvement but not a drastic one, if that's what you are expecting for, you need to get serious about it, a SP4 18 or X18 could be options that could work on the space you currently are using, you could go multiple drivers but that will add cost and likely will take more space.  

 

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Thanks for the reply Joe! Another person i was hoping to hear from. Currently as a minimum, 1000 wrms is going to the OA-18. Understood @ output penalty. Was strongly considering an X-18 but the space required is coming up to over 9ft^3 gross which is a bit too much unfortunately. The current enclosure is 7ft^3 gross & my entire trunk is basically gone O_o

The amp i will be upgrading to will be between 2000wrms & 2500wrms. Was advised to put more than the rated 1500wrms on the X-15. Is this mandatory or will i get good performance with "rated power"? 

If i decided on multiple drivers, from what i'm seeing the cost will be almost the same. So will the enclosure size. Basically it depends on what will out-perform what in terms of low-end output & do it more comfortably.

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9 hours ago, image91 said:

Thanks for the reply Joe! Another person i was hoping to hear from. Currently as a minimum, 1000 wrms is going to the OA-18. Understood @ output penalty. Was strongly considering an X-18 but the space required is coming up to over 9ft^3 gross which is a bit too much unfortunately. The current enclosure is 7ft^3 gross & my entire trunk is basically gone O_o

The amp i will be upgrading to will be between 2000wrms & 2500wrms. Was advised to put more than the rated 1500wrms on the X-15. Is this mandatory or will i get good performance with "rated power"? 

If i decided on multiple drivers, from what i'm seeing the cost will be almost the same. So will the enclosure size. Basically it depends on what will out-perform what in terms of low-end output & do it more comfortably.

For what you want to do, I don't think the X-15 is going to be much of an improvement.  Like Joe said, you are going to lose some efficiency from the smaller cone size, and while you can make up for that with some more power in the end you just aren't going to gain a whole lot.  

My suggestion would be to get a different 18" that has more motor strength AND can take more power.  An Fi SSD Neo 18 could handle 2500 watts just fine and would be a good choice.  There are other good choices as well. 

"Nothing prevents people from knowing the truth more than the belief they already know it."
"Making bass is easy, making music is the hard part."

Builds:

U7qkMTL.jpg  LgPgE9w.jpg  Od2G3u1.jpg  xMyLoO1.jpg  9pAlXUK.jpg

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You wouldn't happen to be in texas would you? I'm selling my DD 9518...

What vehicle are you working with?

18 Sierra 6.2 Z71 : 3 F8L's, DD M2a @.67, 1.95@33

05 TL build log SOLD

04 YukonXL : jvc kw-v51bt , RE 6.5c, 4 jbl gt5 12s, Memphis pr1000.1 5.5 cu.ft. sealed

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10 hours ago, image91 said:

Thanks for the reply Joe! Another person i was hoping to hear from. Currently as a minimum, 1000 wrms is going to the OA-18. Understood @ output penalty. Was strongly considering an X-18 but the space required is coming up to over 9ft^3 gross which is a bit too much unfortunately. The current enclosure is 7ft^3 gross & my entire trunk is basically gone O_o

The amp i will be upgrading to will be between 2000wrms & 2500wrms. Was advised to put more than the rated 1500wrms on the X-15. Is this mandatory or will i get good performance with "rated power"? 

If i decided on multiple drivers, from what i'm seeing the cost will be almost the same. So will the enclosure size. Basically it depends on what will out-perform what in terms of low-end output & do it more comfortably.

 

If multiple drivers is the way to go and don't mind the expense, simply two X12s would do the job in 5 net and could be run on 2.5K all the way to 4K+. 

So then we model 1 X18v2 in 7net@32Hz, 1500W power (in yellow) vs in 2 X12v1 5net@32Hz, 3000W power (in red):

212vs118.jpg

 

So it seems both options basically match output with the two X12s pushing ahead at tuning quite a bit, no doubt the single X18 is a more inexpensive setup but if you really want the smaller box there is a way too.

 

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