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Discussion Starter · #1 ·
I made a major speaker upgrade recently and in order to help offset some of the (unexpected) costs, decided to sell my very much loved Seaton SubMersives (4 of them) and try DIY.

While I had 4 SubMersives, 3 is more than adequate (in fact, two are and is what I started with) but my OCDness would not allow the required asymmetrical subwoofer placement. The original room I had the SubMersives in was in a concrete basement. I am now in a converted loft on the 2nd floor so I am limited by my concerns over structural integrity of the room/house on how much woofage I dare put in this space.

A fellow AVSer (CraigJohn) in whose ears I trust and also a SubMersive owner, had heard some DIY subs done by Gorilla88 and in Craig's words, those DIY subs "killed" his SubMersives. At the time, Gorilla88 had, if I recall correctly, 6 or 8 of the SI HT18's running so that is the direction I started in.

To reduce the space requirements of that many cabinets, I then decided to try to find a dual-opposed cabinet utilizing SI HT18's but the availability of those cabinets did not meet my time requirements.

So back to single 18 inch enclosure and have ordered 4 of the flat packs from Parts Express. Given the reduction in the number of cabinets (from the 6 to 8 that Craig heard at Gorilla88's), I have ordered 4 of the SI HST18's (vs HT18's) and will see how they perform vs my needs/wants and previous experience with my SubMersives). If those 4 turn out to fall short, I will just keep adding boxes until I get there. Sound is such a personal preference thing, and while I have received all kinds of opinions, I thought I would start "small" and add as necessary. I am cautiously optimistic that these 4 will do the job. (My room is about 3400cf).

Pieces I need to get up and running:

Drivers: 4 HST18's (D2) on the way

Amps: I have two Peavey 7500's on the way. I plan on running the HST's at 4 ohms so one amp in 4 ohm mode will drive 2 cabinets

DSP: I have a miniDSP in house

Cabinets: 4 On the way

Paint: 2 Gallons of Duratex and 4 rollers are on the way

Glue: Titebond II in house

Clamps: Going to Harbor Freight Tools this weekend (we live in a very small community) to buy a bunch: How long does it take for these cabinets to dry enough so that I can remove the clamps and glue the next cabinet.

Spackle: The folks from Acrytech who make Duratex recommended Ace Hardware Vinyl Spackle so will find an Ace Hardware when we make our trip this weekend.

Connectors: It has been recommended that I use Neutrik speakON connectors. I still need to research this and also determine what kind of connector the amps use.

Lastly, screws/connectors/fasteners for the drivers to connect to the enclosure. It has been recommended to use PE's Hurricane nuts + hex socket screws so I will investigate those as well.

If I have left anything out (a real possibility) I would appreciate any feedback.

I have no doubt that I will eventually get these all constructed (I have about 4 weeks until my 4 SubMersives leave the premises). But most importantly, I am anxious to see what kind of FR I am able to achieve. The FR from my current subs in their current locations is ruler flat being down about 5db at 7hz.



I am looking to meet that AND have the same sound quality/impact.

We shall see.

Thanks
 

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The mounting depth on the HST18 is 11" and if the PE flat pack is spec'ed the same as the 4cf flat pack at DIYSG, you will need to modify the internal bracing to accept the 11" depth of the driver. I would do a dry fit of the box and measure the depth to double check if you have enough clearance. :)
 

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Discussion Starter · #3 ·
The mounting depth on the HST18 is 11" and if the PE flat pack is spec'ed the same as the 4cf flat pack at DIYSG, you will need to modify the internal bracing to accept the 11" depth of the driver. I would do a dry fit of the box and measure the depth to double check if you have enough clearance. :)
Ooops !! It is the exact same product.
 

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Ooops !! It is the exact same product.
I had an existing 4cf box from DIYSG with a SI-HT18 installed and had to cut a portion of the long brace out for the HST-18 to fit properly. It will be a lot easier to do this before you assemble the box. Like I said before, do a dry fit first and measure to determine how much to remove...IIRC, you will need .5" to 1.0" of additional clearance for the HST driver.
 

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Titebond II says 30 minutes clamp and 24hrs before loading the joint. Considering the total weight of the enclosure some of the joints will be loaded simply by removing the clamps, so err on the side of caution, but I'd feel safe in unclamping after a few hrs.

I have been using the square metal speakon jacks, but just ordered some of the rounds as well. Looking at the spade terminals on the back and the connections in the jack I would use the square metal ones for this build. They are quite a bit more robust in connection terminals.



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Also. I saw someone looking for the correct size screw for the speakons- in irder to get a flush/clean look- you can see in the pics that the M3 bolts I use make the grade, but I am putting a washer and but on the inside which is a bit more work than most would prefer- I just don't like coarse thread screws in MDF. Probably due to so much exploding Walmart/ikea furniture in my younger years.


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Also. I saw someone looking for the correct size screw for the speakons- in irder to get a flush/clean look- you can see in the pics that the M3 bolts I use make the grade, but I am putting a washer and but on the inside which is a bit more work than most would prefer- I just don't like coarse thread screws in MDF. Probably due to so much exploding Walmart/ikea furniture in my younger years.
Do you have a source you can share for those bolts? Those are nice!
 

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Discussion Starter · #11 · (Edited)
Did you tune the submersives with the minidsp?
No. The miniDSP will be used to lift the lower end (below 30hz) to flat. But since I have it, I may flatten out two very small "humps" so that Audyssey (or Dirac or ...) sees a flatter response.

I may also use it to set trims and distances for the front and rear subs. I let Audyssey do this with my current subs and it never got it right. This will also allow me to run all four subs off of one sub out on my Marantz (for whatever that is worth).
 

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Yea, audyssey sucks for bass eq. It is a good idea to run all subs on the same output because you can set delays with your dsp and let audyssey or whatever other room correction software tune the subs collectively. I too like to tune the subs before room correction software is run, so that it has less work to do and your sub baseline tune will always be there if you were to ever need to run the room correction software again for whatever reason.
 

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Discussion Starter · #13 ·
4 Boxes delivered today. Note the directions of the arrows. Apparently UPS wasn't sure what an arrow meant !!



Blue tape to see how it all goes together.





Is there any reason that I should not apply glue and then use a brad-nailer to skip the clamping step? I can set the air compressor to set the head just below the surface and the paint I'm using should certainly hide any tiny holes. It sure would save a fair amount of time. I would glue/nail the front piece on but glue only the beveled piece and use weights to hold it in place.
 

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Discussion Starter · #14 ·
Yea, audyssey sucks for bass eq. It is a good idea to run all subs on the same output because you can set delays with your dsp and let audyssey or whatever other room correction software tune the subs collectively. I too like to tune the subs before room correction software is run, so that it has less work to do and your sub baseline tune will always be there if you were to ever need to run the room correction software again for whatever reason.
"sucks" may be a bit strong but for multiple subs not equal distance from the MLP, it never seems to get it right. The other key issue I have with Audyssey is the sub 20hz output. Audyssey claims it corrects down to 10hz but in my case, I can easily prove the it screws up the bass below 20hz.

Maybe "sucks" is the right word :D
 

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"sucks" may be a bit strong but for multiple subs not equal distance from the MLP, it never seems to get it right. The other key issue I have with Audyssey is the sub 20hz output. Audyssey claims it corrects down to 10hz but in my case, I can easily prove the it screws up the bass below 20hz.

Maybe "sucks" is the right word :D

no, IMO it definitely sucks. It doesn't even get the delays set correctly with the mains. It does get close, but not perfect. Maybe sucks is a little harsh, but I am not a fan of audyssey bass eq in any manner.


I think on diysoundgroup's website, they says that you can use brad nails to make the build go by faster. Just cut out some of the bracing for the massive motor on that driver and all will be well. This sub is a great choice and I would have bought four of them instead of the UXL's, but the UXL's have a shallower mounting distance and that was crucial for my hidden sub placement with two of them.
 

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Discussion Starter · #16 ·
I think on diysoundgroup's website, they says that you can use brad nails to make the build go by faster. Just cut out some of the bracing for the massive motor on that driver and all will be well. This sub is a great choice and I would have bought four of them instead of the UXL's, but the UXL's have a shallower mounting distance and that was crucial for my hidden sub placement with two of them.
The bracing should only need to be cut like an 1/8th inch or 1/4th of an inch. The stated mounting depth of the HST is 11 inches for the driver and I measure a smidgen under than between the brace and the cabinet face where the driver frame will sit. We shall see.

By the way, I have a friend who is having a home built in the mountains that will be a show home for 18 months. We designed the theater and have "borrowed" your staggered panel look. The interior designer LOVED that look only it will be with light colored panels!!.
 

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...Is there any reason that I should not apply glue and then use a brad-nailer to skip the clamping step? ...
I don't believe nailing tightens the joint as much. I would clamp (to compress the glue and tighten the joint) then nail. Once nailed, move the clamp to another position, repeat.
 

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Discussion Starter · #18 ·
I don't believe nailing tightens the joint as much. I would clamp (to compress the glue and tighten the joint) then nail. Once nailed, move the clamp to another position, repeat.
Great idea! Thanks
 

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Good luck w/your build. I'm looking forward to pics and your impressions of four of these bad boys.

Also wanted to add that the discussion of Audessey/MiniDSP/how many channels of sub to run is very interesting to me. In a few months I'll be setting up my new HT and using Audessey XT32 for the first time. I already bought a MiniDSP specifically for the subs. Guess I have a bunch of reading to do in advance.

Good luck w/the build!
 

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The bracing should only need to be cut like an 1/8th inch or 1/4th of an inch.
I gave mine a bit more space due to the pole vent...between .5" and 1.0". You can see a picture of the back plate at data-bass:

http://www.data-bass.com/data?page=driver&id=55

You might want to double check with Nick and see what he recommends...:)

BTW, you are going to love this driver. I have an aggressive low shelf filter set on my DCX2496 and this driver just pounds the low stuff.
 
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