Whole buncha sub designs for the RSS210HF-4

[Paul Carmody]

I've been playing around with various enclosures for this driver. It's a bit of an odd driver, in that while it can go very low in a vented box, it doesn't necessarily go all that loud. In this case, the box is 30 Liters, tuned to 25 Hz. This gets us an F3 of 23 Hz; very nice! Problem is, those low notes will max out excursion at 100 dB (@ 70 watts)

So what can we do with this? Certainly, it's not going to work for large-scale home theater. However, this could definitely work for music lovers who want to make sure they hear the lowest octaves out of their recordings. Such people usually listen at more reasonable volumes (say, 85 dB), and the driver and amp should be very comfortable there. By many accounts, The RSS210 is a very high-quality sub, and it should provide a much higher fidelity than, say the Dayton SD215-88 (don't get me wrong, that's a great driver, too). It would also work for small home theaters. It may be a little big for computer users, but who am I to say?

I came up with three different design ideas.

The Pony - A speaker-stand-turned-sub. Driver can be front or side-mounted. It uses a slot vent for no particular reason; I just wanted to see if I could draw it. One could just as well use the vent from the Burro--or maybe the vent from the Turtle.

The Burro - A rectangular prism. Sits lower to the ground. Driver is side-mounted (magnet carefully placed to keep center of balance). Meant to be tucked next to furniture or an entertainment center. It uses 3" PVC, a lot of it.

The Turtle - A simple cube. For some reason, this is a popular shape for subs. I never understood why. It's pretty much impossible to use 3" PVC in this box, and a slot port would be too much extra work. So as a compromise, I think the 2" Precision Port kit should work. The port is downfiring because I was concerned about chuffing and because the flare is so large it won't fit on the back.

The cabinet walls won't need to be lined unless you cross really high (there is a pipe resonance at 250 Hz).

These are just concepts. I haven't built any of them yet--but I will. I am confident that they will work, though, and since this sub driver has come up lately, I thought I'd share some useful ideas. Click below for diagrams.

[fastbike1]

I'm not sure how you're getting an F3 of 23Hz. I've also been looking at an RSS210HF model in, surprisingly, 31 liters. Even tuned to 25 (my tuning at 27), I can't get F3 below 27Hz.

Everything else matches your comments. Excursion an issue below F10 (~22Hz). Models 102dB w 60W.

FWIW, the Aurasound 10 in 30 liters plays almost as low (f3 33) and noticably louder (105dB) for a bit less money. No excursion issues either.

[Paul K.]

Some of us actually listen at even lower SPLs, like 75-80 dB average, without missing out on any of the music!
Paul

[QUOTE=Paul Carmody;1688635]
However, this could definitely work for music lovers who want to make sure they hear the lowest octaves out of their recordings. Such people usually listen at more reasonable volumes (say, 85 dB), and the driver and amp should be very comfortable there.

[Pete Schumacher ®]

Some of us actually listen at even lower SPLs, like 75-80 dB average, without missing out on any of the music!
Paul

However, this could definitely work for music lovers who want to make sure they hear the lowest octaves out of their recordings. Such people usually listen at more reasonable volumes (say, 85 dB), and the driver and amp should be very comfortable there.

You know Paul, that orchestral work I played in Iowa has quiet parts that are very tough to pick up unless I'm letting the amps put out in the range of 80W+ peaks.

I definitely find myself turning it up on such tracks, since the average levels are quite a bit lower than most rock/blues/jazz. And without adequate power, the crescendos seem to lose a bit of luster.

I suppose that during the more "normal" passages, the ambient levels are somewhere around 85dB range.

[Paul Carmody]

I'm not sure how you're getting an F3 of 23Hz. I've also been looking at an RSS210HF model in, surprisingly, 31 liters. Even tuned to 25 (my tuning at 27), I can't get F3 below 27Hz.

If you use PE's specs, you are correct. I used Zaph's measurements. Not sure who is more correct; guess I could measure my pair.

FWIW, the Aurasound 10 in 30 liters plays almost as low (f3 33) and noticably louder (105dB) for a bit less money. No excursion issues either.

Well, that is twice as loud, I'll give you that. But in my opinion, 33 Hz is in the range of "low bass," where once you get down below mid 20 Hz I'd consider that "sub bass." Not everyone needs sub bass, especially people who mostly listen to music recorded before 1990. On the other hand, for other people, once you hear sub bass, it's hard to go back.

[Paul K.]

Just to clarify, my average level of 75-80 dB SPL is at my listening position, not a 1 meter distance. What you say is true; orchestral music typically has a much larger dynamic range than most any other kind of music and sometimes, if you set the volume to not overdo it when the orchestra is playing fff, you may not be able to hear the ppp movements very well.
Paul

You know Paul, that orchestral work I played in Iowa has quiet parts that are very tough to pick up unless I'm letting the amps put out in the range of 80W+ peaks.

I definitely find myself turning it up on such tracks, since the average levels are quite a bit lower than most rock/blues/jazz. And without adequate power, the crescendos seem to lose a bit of luster.

I suppose that during the more "normal" passages, the ambient levels are somewhere around 85dB range.

[lamski]

Paul, thank you for posting these. Just what I was looking for. Should be a nice compliment to the rs microbes I'm building.

[fastbike1]

No need for . I'd go w/ Zaph's measurements. I'd also agree that <mid 20's isn't music either. That's what you were saying right .

Not arguing, just trying to check my modeling.

If you use PE's specs, you are correct. I used Zaph's measurements. Not sure who is more correct; guess I could measure my pair.


Well, that is twice as loud, I'll give you that. But in my opinion, 33 Hz is in the range of "low bass," where once you get down below mid 20 Hz I'd consider that "sub bass." Not everyone needs sub bass, especially people who mostly listen to music recorded before 1990. On the other hand, for other people, once you hear sub bass, it's hard to go back.

[Wolf]

^^^Those are my measured specs above. In 28.3 ltrs, I get an F3/10 of 26/19 with a 30 Hz Fb, with a 2.5" diameter x 10.5" long port.

Later,
Wolf

[B_Rich]

Hmm, I may potentially be the guinea pig on the Pony design. I'm building the Overnight Sensations (as you know, Paul) and I'm using the RSS210HF as a sub. It'll be going underneath my desk, mainly being used for my computer (but I don't want to build it around my computer, I want it to be an "all purpose" design as much as possible).

Right now I'm torn between 3 designs.

Mine: 1.8 cubic feet tuned to 22hz, which may not be ideal as the size of the box is pretty big, and Wolf tells me that xmax will be reached really quickly down in the mid 20's. But, this obviously gives me the best frequency response, which I like to see. I know simulations aren't everything, but they give me an idea.

Wolf's: which is 1 cubic foot with a 2.5 ID port, 12.5in long, which yields a tuning frequency of 30hz. He used these parameters in the Attitudes build. I plug in these parameters, and the graph looks decent (to my uneducated mind) and could be better (to my uneducated mind).

Yours: the Pony design. This really appeals to me, as the dimensions are more than perfect. Any chance you had anymore information on it? Net size, port tuning, F3, etc. Unless, what you said for your original numbers at the beginning of the post were for all 3 designs.

I'm really looking to "loose nothing" with this sub build. I'd like it to dig as low as possible while being as flat as possible.

Thanks for posting up the designs, Paul.

[Wolf]

Wolf's: which is 1 cubic foot with a 2.5 ID port, 12.5in long, which yields a tuning frequency of 30hz. He used these parameters in the Attitudes build. I plug in these parameters, and the graph looks decent (to my uneducated mind) and could be better (to my uneducated mind).

(on a break from work...)
You mean 10.5" long...
Later,
Wolf

[B_Rich]

(on a break from work...)
You mean 10.5" long...
Later,
Wolf

Right.

Edit: and I'll be using the Parts Express 240w sub amp to power it. I know it may be a little much for it, but it's what I have right now and I don't see the need to upgrade/change anything since I already have it.

[MrkCrwly]

The multi size box alternative for a design is a great idea. There has to be space for one of them in any living area without alienating the signif. other.
Well done.
It is amazing that a sub that we call small, would be considered large by the "unwashed" masses. A whole lot of HT systems come in 1 box.

[benchtester]

...It is amazing that a sub that we call small, would be considered large by the "unwashed" masses. A whole lot of HT systems come in 1 box.

OT- tell me about it: I gave 7.5"x8.5"x13.5" speakers to a friend in a one bedroom apt. as her primary speakers. After 3 years she returned them because she was remodeling and they were "just too big". (But now they're my office speakers, so there!)

On T - I will be using the RSS210 as my woofer in a three way system but I am in a fourth-floor condo (so I am concerned about neighbor complaints). What's everyone's opinions: go with these vented alignments? go with a sealed version which may be less offense to neighbors? Is there a rule of thumb about what frequencies transmitted through floors?

[Paul Carmody]

Right now I'm torn between 3 designs.

Mine: 1.8 cubic feet tuned to 22hz, which may not be ideal as the size of the box is pretty big, and Wolf tells me that xmax will be reached really quickly down in the mid 20's. But, this obviously gives me the best frequency response, which I like to see. I know simulations aren't everything, but they give me an idea.

Wolf's: which is 1 cubic foot with a 2.5 ID port, 12.5in long, which yields a tuning frequency of 30hz. He used these parameters in the Attitudes build. I plug in these parameters, and the graph looks decent (to my uneducated mind) and could be better (to my uneducated mind).

Yours: the Pony design. This really appeals to me, as the dimensions are more than perfect. Any chance you had anymore information on it? Net size, port tuning, F3, etc. Unless, what you said for your original numbers at the beginning of the post were for all 3 designs.

I'm really looking to "loose nothing" with this sub build. I'd like it to dig as low as possible while being as flat as possible.

Good question. Actually, Wolf's design and mine are pretty close. I think he was going for exactly 1 cu ft (~28.3 Liters), where I rounded up to 30 Liters
Wolf's tuning is slightly higher than mine, but that is a matter of personal taste, and can often be easily changed by shortening or lengthening the port.

Yes, all 3 of my designs here are 30 Liters, and all are tuned to 25 Hz.

Honestly, I think yours is awfully big. I understand wanting the lowest F3 possible, but is it worth it to increase the box size by 50-100% just to eke an extra 3 Hz? Besides, you're at a computer; I'd think space is at a premium.

If you do the Pony, realize that you don't have to do the folded slot port, unless you're feeling adventurous. 3" PVC would be much easier (and like I said, the 2" Precision Port should work; in theory, anyway)

[B_Rich]

You make a great point on the enclosure size vs. performance gained.

I don't mind doing the slot port, that's all I've done with my past subwoofer boxes for my truck anyway. If I went with that 3" port, it would be my first round port that I've ever done, which I'll probably end up doing. I do like that yours is tuned lower, and it fits underneath my desk perfectly.

I have a week before I start making cuts, so there is still time.

[Paul Carmody]

On T - I will be using the RSS210 as my woofer in a three way system but I am in a fourth-floor condo (so I am concerned about neighbor complaints). What's everyone's opinions: go with these vented alignments? go with a sealed version which may be less offense to neighbors? Is there a rule of thumb about what frequencies transmitted through floors?

I'd be interested to hear those rules of thumb! As a general rule, bass frequencies are long, so they don't care about walls and floors. (Party on!)

<begin pontification>
I am developing a theory that a lot of people like sealed subs because they are easier to integrate. In my experience, trying to balance a vented sub by ear just never seems to work (see: equal-loudness contour). They tend to sound boomy and overbearing. HOWEVER, if you break out the SPL meter, or have Audessy EQ, then vented subs can integrate very well and seamlessly.

Sealed subs have that gentle roll-off, which I think allows for quite a bit of forgiveness in terms of integration and therefore are difficult to sound "boomy." And when your sub doesn't go boom, it sounds "quicker" or "tighter." It's not that sealed subs are actually tighter or quicker, it's just that they are easier to integrate than vented subs. A properly level-matched vented sub won't go "boom;" and thus it will then sound "tight" and "quick," and in fact you'd be hard pressed to find the transition.
<end pontification>

[Mayhem13]

Great design on the Pony Paul, a sensible option to a space robbing speaker stand, and an effort well worth undertaking for those with bookshelf speakers. The addition of a pair of these would allow for a 100hz+ crossover point really freeing up the midrange from the mains.....plus they'd look so cool!

I was thinking of starting a discussion on the placement of the driver in such a design as how it relates to the floor and the MT section.....seein as how i'm building a pair of 'ponies on crack' right now with the RSS315HF. Haven't cut the baffle hole yet so............

[Paul Carmody]

Here are the graphs to show the predicted response. You're going to get pretty much the same thing out of all three enclosures--except that the one using the 2" Precision Port will not have as much of a pipe resonance, and it also might have higher port velocity.

[Jethro]

Paul, those are some very well thought out designs -- nice work.

But I have to ask the question... why use an 8" driver that will limit output, when you can use the RSS265HF-4 in a smaller enclosure with similar FR, but a decent amount more output? In the case of the Pony design, you could just mount the 10 on the side of the enclosure instead of the front (NHT 3.3 style). I guess the $30 difference in price makes the difference for some, but that's about the only benefit I see to using the 8.