So, I have been toying around with a few sub ideas after building a pair of sealed Tritrixs. I was first looking into going for a cheaper 10" or 12", then was interested in the Dayton Reference 12"HF; and am now figuring that for just a bit more money, I could have a 15"HF (Parts-Express.com:*Dayton RSS390HF-4 15" Reference HF Subwoofer 4 Ohm | subwoofer rss390hf-4 15" subwoofer dayton reference rs sub dayton loudspeaker. I am planning to pair this with a BASH 300. Looking at building a 3-4 cuft sealed box (currently living in an apartment).
I am liking this idea because the 15" will leave me pleanty of room for expansion when I get a larger place in a couple years.
In a small ~12x15 room, would the 15" be overbearing/overpowering; or could I manage it to perform well with movies and music? Would I be better off with a smaller driver?
Opinions, ideas, and anything else you can throw at me!
Thanks!!
I am liking this idea because the 15" will leave me pleanty of room for expansion when I get a larger place in a couple years.
In a small ~12x15 room, would the 15" be overbearing/overpowering; or could I manage it to perform well with movies and music? Would I be better off with a smaller driver?
Opinions, ideas, and anything else you can throw at me!
Thanks!!
I like your style
I did not have time yeaterday to read much about the Linkwitz circuit info you gave me, but it looks interesting; I will read more into it tonight. Thanks again!!!
Thank you, Chris.
This does look a little complex for a beginner like me. Is designing one of these easier than it looks? Have you been through the process?
I was also eyeing the Dayton 500w amp with eq. Would I realize a signifigant improvement for the extra $75? ( http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-806)
Walt
Last edited:
Yes, I've been through it - it was my first serious project.
The idea is that your woofer will roll off at a frequency, at a rate of 12dB per octave. So, if we set a circuit where it increases amplifier output by 12dB per octave below the roll-off frequency, you can have flat response as low as you like. As it says on the site, the more gain you apply (ie, the lower you eq it to), the lower the maximum volume will be.
The circuit itself is fairly small, but will need a power supply (I just took it from the amplifier power supply), and you can go as low as you want.
If you want, I'll design the box etc for you, and give you the component values for the circuit.
The amp you just showed has eq that you wouldn't need, as you'd use you own.
If there's any specific bits you want me to simplify, let me know.
Chris
The idea is that your woofer will roll off at a frequency, at a rate of 12dB per octave. So, if we set a circuit where it increases amplifier output by 12dB per octave below the roll-off frequency, you can have flat response as low as you like. As it says on the site, the more gain you apply (ie, the lower you eq it to), the lower the maximum volume will be.
The circuit itself is fairly small, but will need a power supply (I just took it from the amplifier power supply), and you can go as low as you want.
If you want, I'll design the box etc for you, and give you the component values for the circuit.
The amp you just showed has eq that you wouldn't need, as you'd use you own.
If there's any specific bits you want me to simplify, let me know.
Chris
Looks to me like this woofer is perfect for sealed with eq. on it's own, f3 of 30Hz (very respectable), most would be happy with this. This is in a 152L box, which isn't small.
If you wanted to go to 20Hz, you wouldn't need to put much extra power in (+8dB compared to the +14 I've used).
You could get away with a very small box here. 50L will be fine, just need more power.
What kind of SPLs will you be asking of this sub?
Last edit - try the attached spreadsheet. Put the Qts, Vas and Fs of the driver in, leave the desired Q at 0.7, tell it how low you want to go, in what box size, and it will work out how much gain you'll need, and the component values for the circuit.
If you wanted to go to 20Hz, you wouldn't need to put much extra power in (+8dB compared to the +14 I've used).
You could get away with a very small box here. 50L will be fine, just need more power.
What kind of SPLs will you be asking of this sub?
Last edit - try the attached spreadsheet. Put the Qts, Vas and Fs of the driver in, leave the desired Q at 0.7, tell it how low you want to go, in what box size, and it will work out how much gain you'll need, and the component values for the circuit.
Last edited:
You could consider an isobaric design (push/pull) where you mount two identical drivers facing each other, and out of phase with each other. This reduces the cabinet volume needed by half, and also increases sensitivity.
I have two Radio Shack 12's like this with a 200w plate amp, and it gets below 20hz.
I have two Radio Shack 12's like this with a 200w plate amp, and it gets below 20hz.
Chris, Thank you so much for your help!!
I did not see the spreadsheet you posted, please repost. I have been using Winisd and it looks like, with no eq, I can achieve pretty decent results from a ~3 cuft box. I am beginning to understand the principal behind the LT circuit, and it looks very interesting. Again, right now I am a little worried of doing something wrong and frying a good driver or amp. But, at the same time...I do like to experiment.
I am not too demanding in terms of SPL. Since I am in an apartment right now, I will be listening to it at low to moderate levels. However, when I move to a house in a couple years, I am sure it will be turned up a bit at times...but I also have no issues redesigning it when the time comes. I am thinking of going with this larger driver because I would like to avoid the cost of upgrading the driver later down the road, just the box.
I will read more on LT circuits tonight and see if the design/construction makes more sense to me.
Thanks again!
Walt
I did not see the spreadsheet you posted, please repost. I have been using Winisd and it looks like, with no eq, I can achieve pretty decent results from a ~3 cuft box. I am beginning to understand the principal behind the LT circuit, and it looks very interesting. Again, right now I am a little worried of doing something wrong and frying a good driver or amp. But, at the same time...I do like to experiment.
I am not too demanding in terms of SPL. Since I am in an apartment right now, I will be listening to it at low to moderate levels. However, when I move to a house in a couple years, I am sure it will be turned up a bit at times...but I also have no issues redesigning it when the time comes. I am thinking of going with this larger driver because I would like to avoid the cost of upgrading the driver later down the road, just the box.
I will read more on LT circuits tonight and see if the design/construction makes more sense to me.
Thanks again!
Walt
Brings back memories. I once built a 15" sub in a 6-8 ft^3 ported box. The design was successful and I thought it sounded good. Probably got into the low 20s. Unfortunately, no matter how much I reduced the level, some people found it disturbing- to the point of getting headaches at levels I could barely detect. Infrasonics? The female response to a large black box in the living room? Just not used to response that low? Whatever it was, it had to go. 
Brings back memories. I once built a 15" sub in a 6-8 ft^3 ported box. The design was successful and I thought it sounded good. Probably got into the low 20s. Unfortunately, no matter how much I reduced the level, some people found it disturbing- to the point of getting headaches at levels I could barely detect. Infrasonics? The female response to a large black box in the living room? Just not used to response that low? Whatever it was, it had to go.
Just when I got excited when my girlfriend said she didn't care what was in the living room as long as it had a nice finish and sounded good....This is actually something that I was worried about when considering something of this magnitude. I got excited when I started choosing a driver, I just started "one-upping" all of my previous ideas.
Do you feel that a smaller sub is a more pleasant and enjoyable creature for a living room atmosphere (movies, TV, music, background music for small get-togethers)?
Thanks for your input,
Walt
Well, I'm a big Bach pipe organ fan, so the biggest sub is just right. I'm not sure about smallish subs since I run a three way active crossed system and can use whatever I want for the bottom end. It just seems easier to build a bit larger woofer system, than to go to the trouble of adding a small sub. Obviously many commercial manufacturers have found it a good choice, but IMO a sub is to accomplish what's impractical in the main system. (I should talk- right now I'm running 8" woofers in oversize enclosures because my old woofers went to woofer heaven.)
Now, another sub I built was a downfiring thing in a large Sonotube, similar to the Hsu subs (though I think I did it several years earlier). That was very practical and sounded good, so a medium sized sub can certainly be satisfying.
BTW, the sub can be ported, but I've never found it wise to try and mate a sub to a ported woofer system. Not that it can't work well, but it's just easier with a sealed system.
CH
Now, another sub I built was a downfiring thing in a large Sonotube, similar to the Hsu subs (though I think I did it several years earlier). That was very practical and sounded good, so a medium sized sub can certainly be satisfying.
BTW, the sub can be ported, but I've never found it wise to try and mate a sub to a ported woofer system. Not that it can't work well, but it's just easier with a sealed system.
CH
I understand what you mean about just building a larger woofer system as being easier. I am new to the diy process so I built the easiest mains I could find, disregarding the low end (sealed Tritrix). But they sound fantastic in the mid to upper fqs!
And this is where my dilemma comes in, I do not want to over-saturate my music with overbearing lows (personal listening is mostly classical-violin/cello stuff; girlfriend is mostly rock and hip-hop) ; but at the same time it would be great to be enveloped in the audio from an action movie! Finding that balance is where I am stuck-I think...Understanding that what sounds good to one person may not sound good to another; I have never had "true" stereo/theater sound at my disposal before, so I am a little lost on where to go or how a good system is "supposed" to sound.
Thanks again for your advice!
Walt
Do give the RSS390HF some power, go with a 500W amp or better. I have some distortion measurements (outdoors 2m groundplane) with the driver in a small box (56L, effective about 72L when filled). Index of /~lmela/dayton I think this driver is very good for the money. I will be using an adjustable two-pole two-zero filter to even out the response for better fit with room gain.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.