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Discussion Starter · #1 ·
My priorities in this order are: music, economics, space saving. Ultimate sub SPL is not important, neither is sub-20Hz sound. This will be the only sub.

I picked up a used Yung plate amp 500w w/bass boost so I am trying to match and build the right sub combo around it.

Due to cost and size, I think this is what I want, the Dayton Audio sealed flat pack with Reference 15":

295-469Dayton Audio RSS390HO-4 15" Reference HO Subwoofer 4 Ohm
Specifications: • Power handling: 800 watts RMS/1600 watts max • VCdia: 2-1/2" • Le: 1.83 mH • Impedance: 4 ohms • Re: 3.3 ohms • Frequency range: 21-600 Hz • Fs: 24 Hz • Magnet weight: 150 oz. • SPL: 87 dB 1W/1m • Vas: 3.87 cu. ft. • Qms: 4.48 • Qes: 0.42 • Qts: 0.39 • Xmax: 12 mm • Dimensions: Overall diameter: 15.29", Cutout diameter: 14.01", Depth: 7.01".
The sealed flat pack combo with the Ultimax 15" driver is $30 more:

295-514Dayton Audio UM15-22 15" Ultimax DVC Subwoofer 2 ohms Per Coil
Specifications: • Power handling: 800 watts RMS/1,600 watts max • Le: 1.31 mH • Impedance: 4 ohms (2 ohms/coil) • Re: 3.4 ohms • Frequency range: 15-1,500 Hz • Fs: 19.5 Hz • SPL: 89.5 dB 2.83V/1m • Vas 7.92 cu. ft. • Qms: 2.4 • Qes: 0.59 • Qts: 0.47 • Xmax: 19 mm • Dimensions: Overall diameter: 15.28", Cutout: 13.78", Depth: 7.55".
I will need a flat pack and I am committed to the Yung plate amp. If I get the combo, the flat pack is 50% off and becomes about $65. The Reference Xmax is 12mm and the Ultimax Xmax is 19mm.

Which 15" sub driver is better for me?

Please feel free to make any other suggestions, but I know you guys would do that anyway even if I didn't ask. It's part of your charm. :cool:
 

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390ho is a good choice and with the flat pack is a good deal.


the motor on the um is a little under powered for a small enclosure. i'd reserve that one for a larger enclosure, but either is fine, really. with 500 watts, not sure you will take advantage of most of the additional excursion offered by the um15.


with only one sub, room effects will be doubly important, so try to leave a little room for fixing those.


thumbs up.
 

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Discussion Starter · #4 · (Edited)
390ho is a good choice and with the flat pack is a good deal.

the motor on the um is a little under powered for a small enclosure. i'd reserve that one for a larger enclosure, but either is fine, really. with 500 watts, not sure you will take advantage of most of the additional excursion offered by the um15.

with only one sub, room effects will be doubly important, so try to leave a little room for fixing those.

thumbs up.
Thanks for the reply. I had taken my thinking on this about as far as I could, and when I couldn't go any further I knew it was time to call in the experts.

I was trying to keep my entire sub build to $300, but you know how budgets go. The combo flat pack kit got me to a level I couldn't have reached unless I could have found a $100 woofer, but there is no sense in pushing the boundary between frugal and just being stupid cheap.

I also knew that with a 500w amp that both of these subs had more potential than a 500w amp would push them. I was undecided on Reference 15 vs the Ultimax because for another $30, that is not the time to get cheap. Your point is well taken that I won't reach Xmax with the Ultimax.

The one thing I really like about the Umax is it scores a 10 for me on the cool factor for its looks. :) But it looks like the 390HO is better suited for my modest needs.

Now, where's that $5 off coupon that Parts-Express keeps sending me? :rolleyes:
 

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You want ugly? Take a look at the ugly mess HSU puts in their TOP end subs....Data Bass has it
THAT is ugly.
Doesn't matter, John is correct...per usual..
 

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Discussion Starter · #6 · (Edited)
Here is a good discussion on the PE discussion board regarding the Dayton RS sub drivers in a sealed design. Their argument focuses on the differences between the RSS390 HO, HO (high output) vs the HF (high fidelity) models.

Since PE does not allow the swapping of drivers in their flat pack/driver combos this may be moot for me, but the information is relevant. A bunch of really smart guys articulate the finer points of matching sub drivers to sub boxes so the rest of us mortals can begin to understand exactly what we want.

Among the combatants are Thread Starter Dr. Morbius who was unhappy with the HO model in the sealed kit, and highly regarded posters Jeff Bagby, Erich, Bill Fitzmaurice, and someone I didn't recognize but who I thought had a solid engineering educational background, Mr. Pete Basel.

http://techtalk.parts-express.com/s...inets-Why-Parts-Express-Why&highlight=Express
 

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I don't want to come off like a know it all, but I don't really agree with most of all the theoretical chatter in the thread. It's esoteric and not terribly practical. The post from Dayton explaining why the HO was better than the HF in a sealed box (motor strength & cone rigidity) was basically totally ignored because some old general forumulas say the HF will work better in a small sealed box. If you simulate both the 15" HO and HF in the same sealed box with the same amount of power you'll find there's not a whole lot of theoretical difference between them in terms of response or output. But that "little" overlooked detail means that HO is much more likely to match the simulation due to its higher motor strength and stiffer cone.
 

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Discussion Starter · #8 · (Edited)
I don't want to come off like a know it all, but I don't really agree with most of all the theoretical chatter in the thread. It's esoteric and not terribly practical. The post from Dayton explaining why the HO was better than the HF in a sealed box (motor strength & cone rigidity) was basically totally ignored because some old general formulas say the HF will work better in a small sealed box. If you simulate both the 15" HO and HF in the same sealed box with the same amount of power you'll find there's not a whole lot of theoretical difference between them in terms of response or output. But that "little" overlooked detail means that HO is much more likely to match the simulation due to its higher motor strength and stiffer cone.
You don't come off as a KIA. :) And if you disagree with the "theoretical chatter", you would fit right in to that discussion, as some very smart guys were disagreeing with each other.

Bill Fitzmaurice posted the kind of stuff I like, which is " divide Fs/Qes, then any value less than 40 was better for sealed." I can do that kind of math. The problem is, the other experts don't all agree with it, and I understand why the disagreements. But from a novice's point of view, how is a guy like me to know?

The practical answer (at least in this case) is I am picking from 3 pretty good options all within a few dollars of each other, so really there can't be a bad choice. But like most of us, I want the BEST of the three!

Who wouldn't? :cool:
+++

*Not that it matters, but for the three 15" sub drivers I was looking at by BFitz's formula, the Umax = 33, RS390 HF = 37 and the RS390 HO = 57. Anything under 40 is better for sealed, 50+ better for vented, in the middle could go either way.
 

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iirc the 15" RS 390 HF is a recommended item for a THT or THTLP
that was almost 2 years ago, but I did get 3 of them, pretty sure it was the HF
THTLP gives more placement options
go for at least 24" wide
response is there for music and most everything else, very economical wrt to build, you could get by with a PE 250 amp
 

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Discussion Starter · #10 ·
iirc the 15" RS 390 HF is a recommended item for a THT or THTLP
that was almost 2 years ago, but I did get 3 of them, pretty sure it was the HF
THTLP gives more placement options
go for at least 24" wide
response is there for music and most everything else, very economical wrt to build, you could get by with a PE 250 amp
Excellent recommendations my friend, I would love to have a THT or two! :) Unfortunately, I have neither the tools nor the skills for such a project.

You could give me Tiger Wood's golf clubs, but I assure you I would still lack the skills to hit a golf ball straight. You could put me in the best wood shop around, and I still would not be able to make a box.

It has to be a flat pack for me. :cool:
 

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^ +1


next anything is gonna be a flat pack
all the mistakes have been made for you to not know or worry about . .
 
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Discussion Starter · #15 ·
I think you'll want to modify the boost circuit and the HPF on the amp in order to get the best out of that driver / box combo, but I'm not sure if that fits within your DIY comfort level.
I haven't yet laid my hands on the Yung (it will be here Monday, in 2 days). My understanding is the boost is not switchable, but frankly I don't know under what circumstance it is most desirable. How does modding the Yung improve things?

I am OK with a soldering iron, but certainly not proficient. What do you have in mind?
 

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I haven't yet laid my hands on the Yung (it will be here Monday, in 2 days). My understanding is the boost is not switchable, but frankly I don't know under what circumstance it is most desirable. How does modding the Yung improve things?

I am OK with a soldering iron, but certainly not proficient. What do you have in mind?
Well, it all depends what you end up building. You will probably want adjust the circuit to set the High Pass Filter (HPF) to a lower frequency if you build something sealed, maybe for ported. And, it is likely the boost isn't in a very useful spot either.

Do you have any plans for an external EQ on the sub like a MiniDSP, BFD, etc? How about some method to measure your in room frequency response?

It most definitely is adjustable (with a soldering iron). You can bypass the boost with two short jumper wires on the bottom of the input PCB, and if you replace two 0805 resistors (on the top of the PCB) with different values you can move the HPF.

This thread on HTS has details on modifying the Yung amps.
 

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Discussion Starter · #17 · (Edited)
Well, it all depends what you end up building. You will probably want adjust the circuit to set the High Pass Filter (HPF) to a lower frequency if you build something sealed, maybe for ported. And, it is likely the boost isn't in a very useful spot either.
6 dB @ 25 Hz bass boost plus fully adjustable phase, gain, and crossover points

(from the PE ad: "
A bass boost option enables the addition of 6dB of EQ centered at 25 Hz, perfect for sealed enclosures and even certain vented box alignments.")

Do you have any plans for an external EQ on the sub like a MiniDSP, BFD, etc? How about some method to measure your in room frequency response?
No, and no. I was going for an econo-build, so I have no external EQ planned.

It most definitely is adjustable (with a soldering iron). You can bypass the boost with two short jumper wires on the bottom of the input PCB, and if you replace two 0805 resistors (on the top of the PCB) with different values you can move the HPF.
I picked up the Yung 500w w/ bass boost for a decent price. I'm not sure if I need BB or even if I want it, but I have it. :) I really don't even need the sub, but I thought I would add it to a 2.0 nearfield setup with my computer, so it's in a small 15x12 room. I will likely be listening to music at low-to-moderate volume most of the time.

This thread on HTS has details on modifying the Yung amps.[/QUOTE

Thanks for the link. Like everything else I do, I'll read it and obsessively think about it. :cool:

Edit: I just read the entire discussion, it was very enlightening. In short, the Yung 500w w/bass boost at 25 Hz is exactly what is needed for a 3 cuft sealed enclosure. What was surprising was to find out the Yung has a subsonic filter that kicks in at 30Hz! Despite that, I think I will run the Yung as designed, and get the sealed combo w/ 390 HO.

Then if I want more horsepower, I'll get a bigger horse. ;)
 

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How'd ya make out with this?

I just ordered (2) RSS390HO-4's to replace the MFW15 drivers I have in my Micros.
They are rated at 3x the power, and they model a bit lower as well, as they are designed for smaller cabinets.
My HT18's are still waiting for cabinets, in the meantime these are a drop in.

Supposed to be back in stock ~ the 12th.

EDIT: since these are 4 ohm drivers, I bought a 6KDSP to go with them. :D
Us poor folks have to deal with the Berry....and that's OK.
 

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Discussion Starter · #19 · (Edited)
How'd ya make out with this?

Funny you should ask, I have my hands on the box right now, doing some gluing. I've been trying to make this a father/son project so my kid can learn something, but at 22 yo, he apparently knows all he needs to and is not interested in any "projects" with the old man so I just started putting it together myself.

I'll use the jig saw to cut out the space for the Yung plate amp. It is clearly marked on the bottom MDF so I need to cut a square in the back panel, then saw off some of the bracing near the center


FYI the kit was double boxed and was in perfect shape from PE. I ordered it on a Saturday and it arrived on Tuesday.

I dry fitted it and I swear all you need is glue and it would assemble perfectly square. The CNC cuts are perfect, edges are all square. It doesn't come with instructions and you really don't need any. I plan on using Locktite PL and then use a few screws for the first front baffle. It has a double baffle.


I ordered some 1 1/2" 10/32 bolts with hex heads in black. They will go with the the 6-prong T-nuts I got from PE. The other thing I ordered from PE was some speaker gasket material in 1/2 inch. It looks like the same stuff you can get from Home Depot, open cell foam with the sticky backing.
Edit: The gasket material is NOT needed, the 390HO driver already has a nice fitted rubber gasket.

Supposed to be back in stock ~ the 12th.

Yeah, you can blame that on me. I was watching PE pretty closely and I snagged the last one about a month ago. :p

[/QUOTE
 
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