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Dayton RSS390HF-4 15" Reference HF Build

post #1 of 38
1/19/10 at 12:33pm
Thread Starter 
Starting this thread up to get ideas for a build on this guy.  I'm thinking I would like to try a slot ported box if I can find a good build for it - otherwise, a medium-sized sealed box is in order (I'm thinking around 5ft3?).  I'll probably end up powering it with either the PE or the BASH 500w plate.  I have seen several different box building softwares around, but I'm not sure if any of them cover a slot port (I think most are designed around a round port).  I'm not opposed to a round port, but think that a slot port would just be "cooler".  I have access to a wood shop full of equipment, so complexity isn't really an issue as far as the build goes.  I'll post the TS parameters here for convenience, as well as the link to the sub at PE.  The box size can be changed if these parameters don't correspond to 5ft3 being an optimal sealed size.

SUB: http://www.parts-express.com/pe/showdetl.cfm?Partnumber=295-468

TS parameters:
* VCdia: 2-1/2"
* Le: 1.00 mH
* Impedance: 4 ohms
* Re: 3.3 ohms
* Frequency range: 18 - 800 Hz
* Fs: 18 Hz * Magnet weight: 150 oz.
* SPL: 90 dB 2.83 V/1m, 87 dB 1W/1m
* Vas: 9.95 cu. ft.
* Qms: 3.10 * Qes: .49
* Qts: .42
* Xmax: 14mm
* Dimensions: A: 15-5/16", B: 14-1/8", C: 6-1/8".
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post #2 of 38
1/19/10 at 2:24pm
I'm a fan of Unibox for calculating my enclosures.  Techically it is an Excel spreadsheet and built-in macro so you must have a decent version of Excel before you can use it.  But according to a few different experts, it is one of the most accurate of the free programs.

Yes, the programs are set up for round ports because they are the most common.  Once you finish your design, convert the round port to a slot port.  If your port has 8 square inches of area, then your slot port is 1x8.  If you want even numbers like that, adjust your round port diameter until you get an even area.

Finally, the BASH 500 from PE may still have the subsonic filter set at 30 hz.  That isn't good if you are going for a low end monster sub.  But the filter document is also on the site and changing the filter requires the replacement of two resistors.
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post #3 of 38
1/20/10 at 5:17am
Thread Starter 
Thanks for the help Robert.  I've used WinISD in the past when I was building a box for my car.  Good info as well on the BASH, I might just go with the PE 500.  I'm currently using the 240W on my old JBL PB12, and it sounds better now than it did new.
Thanks for the heads up on the port conversion too, that makes it a bit easier.  Now to brush up on my math skills :)
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post #4 of 38
1/20/10 at 5:29am
What are your goals for this sub?  Movies only?  Music?  Combination?  If so, percentage of each?

With my DIY sub, I built it to be accurate.  It is + or - 3db from 80hz down to 17hz.  With the Dayton 500 amp, it will help because it comes with a single band of parametric EQ.  You will be able to tame your biggest in-room peak.  It also has a -3db filter in the 55 hz range for use with the Titanic subs.  Those have a very high inductance voice coils.  Your sub has an inductance of 1.00mh.  That is great.  Those subs are supposed to have amazing sound quality.

I'll play around with this sub in Unibox this weekend when I have some extra time.
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post #5 of 38
1/20/10 at 8:49am
Thread Starter 
I would say this is going to be a 50/50 mix on music and movies.  My HT setup is currently in the living room, and we play our music when we entertain off this system from IPOD/CD/etc.  We all enjoy a good movie night (me especially), but music is pretty important too.  I plan on keeping the JBL running as well, and it is pretty punchy, but doesn't have the output in the lower range that I would like.  So, accuracy is important for the music, but I still want the thunder for movies....the best of both worlds I guess :)  I don't think that will be too hard to achieve given the setup.

My living room has a lot of volume if that makes a difference - it is open to the second story.
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post #6 of 38
1/28/10 at 8:39am
Thread Starter 
Robert did you have a chance to play around with the design any?
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post #7 of 38
1/28/10 at 3:34pm
Sorry but no.  Between work and rebuilding a dead PC I've been very busy.  I have a minute here and a minute there to answer easy stuff.  Looks like it may be a snow/ice day tomorrow so I could have some time.

With a 50/50 music/movie ratio I'm thinking a large, sealed box with a Qtc of .5.  Do you have any size constraints?  I'll bet your 5cf box mentioned above turns out to be the one.
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post #8 of 38
1/29/10 at 10:15am
Thread Starter 
No worries!  Well, this is going to be in the living room, so as long as it isn't HUGE it should be ok.  I can always finish the box with something that will get approval from the wife.
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post #9 of 38
1/29/10 at 3:49pm
First, I used the T/S parameters that are on driver's spec sheet, not the ones you listed.  The Vas of 9.9cf is just too large to make any sense.

Sealed - 4.5cf is the optimum size that Unibox determined.  Stuffed with 4.5 pounds of polyfil, it brings the Qtc down to .621.  The Fb is 31hz and the F3 is 25.

Ported - 5 cf with an Fb of 20hz.  If you modify the filter on the amp for lower, you can tune lower.

The BASH 300 is all you need for this sub/enclosure combo.  The 500 would be overkill but be care with the volume control and it will work as well.

You could go with a low tuned, 5cf ported box and plug the ports and get the benefits of sealed.
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post #10 of 38
2/4/10 at 1:37pm
Thread Starter 
Excellent Robert, thanks a ton!  On the ported box (I like the lower tune of that one I think), what are the dimensions for the port?  Now to get the tax money in and start working....
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post #11 of 38
2/4/10 at 2:19pm
Dual 3" ports.  I don't remember the length but you can find that out at http://www.psp-inc.com and their nifty port calculator.

Remember that the volume I give you is net.  You have to account for all bracing, driver, amp and treat the ports as solid objects.
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post #12 of 38
2/8/10 at 6:08am
Thread Starter 
OK, thanks Robert.  Tax rebate should be in within 2 weeks or so, so I'm going to start getting things together.
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post #13 of 38
2/8/10 at 10:21am
Thread Starter 
Oh, on the ports...do you think (2) 3" would be better than a single 4"?  I can use a relatively short 4" and change the tune to 18Hz, still using 5cu ft
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post #14 of 38
2/8/10 at 5:21pm
With a 15" I'd use dual 4" ports but dual 3's are acceptable.  When modeling the sub you have to look at the maximum air speed in the port.  Too fast and it chuffs.
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post #15 of 38
2/10/10 at 11:31am
Thread Starter 

I've been playing around with that port calculator you linked, and those are going to be some very long ports.  Using 5cuft enclosure with a 18Hz tune and dual 4" ports yields something like a 38" port.  That doesn't sound right to me....my box isn't even that long.  Is that a total of 38" or 38" for each?  Sorry, just a bit confused.

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post #16 of 38
2/10/10 at 12:20pm
That's right.  And that is 38" each.  You are running into the many trade-offs of designing a sub.  Do you want large ports that won't make a chuffing noise?  Then they have to be extremely long and they may resonate in the pass-band.  What do you do?  You go with smaller ports that are flared and hope you don't hear the air swooshing in and out of the port.  Your other option is to use passive radiators which may make you go over budget.

If you want to check the math - http://www.diysubwoofers.org/misc/portcal.htm
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post #17 of 38
2/10/10 at 2:08pm
Thread Starter 
Whoa, interesting stuff there Robert.  I think maybe a slot port would fit the bill better in this case.  I'll play around with that some.

EDIT: For converting the round ports to a slot port, I convert the volume of the round to a slot correct?  Not the area?
Edited by John_Bilbrey - 2/10/10 at 2:19pm
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post #18 of 38
2/10/10 at 2:55pm
A round 4" port has an area of 12.566370614359172953850573533118 square inches.  Dual 4" ports are basically 25 square inches.  So if you have a port that is 12.5" wide by 2" tall, it will have to be 38" long.
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post #19 of 38
2/11/10 at 7:32am
Thread Starter 
OK, scratch the slot port design then lol.  I was thinking in terms of total port volume, and the volume of the two 4"x38" ports worked out pretty close (within a few cubic inches) of a 18"x2"x26" slot port, volume wise, which just happened to fit real well into the box dimensions I've been noodling around with.
I'm thinking I'll just up the tune to 20Hz and go with (2) 3" ports....either that or up the volume to 6ft3
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post #20 of 38
2/11/10 at 1:13pm
It's a combination of port area, port length and the enclosure size that gives you the tuning frequency.

Let's say you were going to use dual 15" passive radiators.  Well, each has a cone that is 14" in diameter.  That is like having dual 14" ports.  To get a tuning frequency of 20hz in a 5 cubic foot box, each "port" would have to be 405" or 33.75' long.  It is all about the weight of the air in the port.  If each port needs to be 33.75 feet long, how much does the air weigh?  400g (just a guess), then that's how much moving mass the passive radiator needs to tune the enclosure to 20hz.
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post #21 of 38
12/8/10 at 12:32pm
Thread Starter 

UPDATE: ordering parts, hopefully due by Christmas.  Going with the BASH 500 :)  I do have a question - I didn't see anything on the PE site about the subsonic filter, just some references/tables about modifiying bass boost.  Any more detail on what has to be done to check/eliminate the ss filter?

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post #22 of 38
12/9/10 at 5:44am

The SSF on the BASH 500 is set around 30hz which is way too high for home theater subs.  Use that table to choose the bass boost (+1 db) and cut-off that you want....You can confirm the settings by looking at the resistors when you get it in.

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post #23 of 38
12/10/10 at 6:20am
Thread Starter 

I thought I remembered reading that there wasn't one on that model at the PE forum.  I'll look over there again.

 

EDIT: the 300w is ok, but the 500w will require some modification of the resistors.  Do you know where I can find a how-to?  The spec sheet didn't make a whole lot of sense to me.  Basically I don't think I want the boost, just the SSF changed/removed.


Edited by John_Bilbrey - 12/10/10 at 7:14am
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post #24 of 38
12/10/10 at 9:21am
Thread Starter 

From PE Tech Service:

 

"

John,

The rumble filter on the Bash 500 plate amplifier is fixed and changing it would void the warranty. Unfortunately I don't have any information on the modification.

 

Regards,

 

xxxx"

 

Left his name off to protect the innocent (or clueless).  But, I was able to garner the values I needed from their forums.  It looks like setting R17 to 20K and R18 to 75K will yield a Fs=18 and Q of 1.0 roughly.  Does this sound like it will work out OK?

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post #25 of 38
12/11/10 at 11:20am

That would be perfect for a 20hz Fb (tuning frequency).

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post #26 of 38
12/13/10 at 6:08am
Thread Starter 

Sweet.  Time to break out the soldering iron once this baby arrives.....actually the driver is back ordered until early January, which gives me time to get the enclosure made up and the amp modified.

 

I'll be using 3/4" Birch plywood for the enclosure, it should "finish" up nicer than MDF.  Plus, it is only $9 more than a sheet of MDF.  Going for a gloss black finish to meet WAF.

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post #27 of 38
12/13/10 at 7:15am

Gloss black will show everything under the paint including the wood grain of the fake birch that Lowes and Home Depot sell.  Go with MDF is you want a smooth finish.

 

Cut some of the panels large and then trim them with a flush trim router bit.  Seal all of the edges with sanding sealer.  Spray with a high build primer.  Sand.  Repeat until it is smooth as glass.  In my project, I have a finish primer that I'm going to use once the temp is high enough.  I'll sand with 800 grit for a very smooth finish.  Next is a charcoal metalic followed by numerous layers of clear.

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post #28 of 38
12/13/10 at 7:25pm

This is kinda funny, I joined to answer this thread lol.

 

I built 2 Dayton HF 15's in two separate 5.2 cube sealed enclosures and used Oaudio 500w plate amps. They have an adjustable subsonic filter and they use Bash amps. Just google Oaudio if your interested. My room is 18x14 and they go deep. I too used 3/4" birch. I tested them on tones down to 15hz and they are usable there and it feels like less than 15 sometimes too. Serenity is a real treat.

 

With that said, I'm considering going with two 18" sonotubes (basically a 12' piece of 18" sonotube cut in half) for them at 9 cubes each and tuned to 17hz.

 

One thing you may not know is that there is a nasty impedance spike at 20hz, most subs have one close to fr. I was testing 22hz good, 21hz good but lower, 20...oh no where's my bass! I thought they were done but they picked right back up at 19hz and then on down to 15hz where I quit testing.

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post #29 of 38
12/14/10 at 8:45am
Thread Starter 

Thanks again for the finishing tip Robert :) 

 

MC - good to know, thanks for the info.  I can always make a new box if I'm not happy with the sound from ported enclosure.

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post #30 of 38
12/27/10 at 12:37pm
Thread Starter 

UPDATE: All pieces are in, MDF purchased, ready to begin construction.  I hope to document the build with some pictures.  Also - man, I had forgotten how big a 15" subwoofer is.  I hadn't seen one since "back in the day" when I had 2 Rockford 15s in the bed of my truck under the SnugTop.  Man....that was 20 years ago!

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