Adding a subwoofer to the 5.1

[tejcurrent 13]

I was originally talking to Scott about a Q 18 in my h/t setup, but I have a chance to get a used SSD 15 instead.. I was planning on asking for the copper coils with the recone, just waiting to hear back in the Fi section.

I was goin to use one of the following plate amps with it, so around 500rms at 4 ohms.

Bash 500

http://www.partsexpress.com/pe/showdetl.cf...tnumber=300-752

Dayton 500

http://www.partsexpress.com/pe/showdetl.cf...tnumber=300-806

At the moment I'm leaning more towards the Dayton, but I wasn't sure if it was worth the price difference.

I'm open to any other amp suggestions too.

I asked about the box in the Fi section, but maybe someone can let me know if 15ft net @ 20hz would be good?

Thanks a lot.

[KU40 173]

I have had that Dayton for about 4 years and have never had any problems, so I'd recommend it. I don't have any experience with the Bash though.

[///M5 2,833]

I wouldn't be that concerned with either, both would be fine. I'd also tune lower for HT.

[tejcurrent 13]

Could you recommend a good tuning? I'm completely inexperienced when it comes to h/t, so I'm not totally sure where to start with the build.

Thanks.

[///M5 2,833]

Depends, if you are truly after HT and not music low is 12hz...of course tuning closer to 20hz can make sense as well. As with everything I'd try it out. What threw me was your request for HT. At that point I picture a 15hz starting point or so.

[Robert_J 0]

The BASH amp comes from PE with the subsonic filter set at close to 30hz. The Dayton amp has the SSF set at 18hz. Both are adjustable by changing resistors on the circuit board. You must de-solder/re-solder to complete this. So if that is beyond your capabilities, then don't tune that low.

The Dayton amp has two nice features as well. There is a notch filter around 50hz that is used when paired with the Titanic sub in the kit. This filter will reduce the inductance hump in the response at around 50hz. It also has a one band parametric EQ. Those are very nice in taming the sub's in-room response. It does take some software and some hardware to properly measure your room and correctly set up the PEQ. Minimum requirement is a Radio Shack SPL meter (every home theater nut should own one) and spreadsheet software (Microsoft Excel is preferred due to the ability to run spreadsheet macros).

15 cf tuned to 20hz with 500w of power and an 18hz SSF looks very good when modeled in Unibox. I would use a pair of 4" Aeroports to keep the port noise to a minimum.

-Robert

[tejcurrent 13]

Depends, if you are truly after HT and not music low is 12hz...of course tuning closer to 20hz can make sense as well. As with everything I'd try it out. What threw me was your request for HT. At that point I picture a 15hz starting point or so.

The BASH amp comes from PE with the subsonic filter set at close to 30hz. The Dayton amp has the SSF set at 18hz. Both are adjustable by changing resistors on the circuit board. You must de-solder/re-solder to complete this. So if that is beyond your capabilities, then don't tune that low.

The Dayton amp has two nice features as well. There is a notch filter around 50hz that is used when paired with the Titanic sub in the kit. This filter will reduce the inductance hump in the response at around 50hz. It also has a one band parametric EQ. Those are very nice in taming the sub's in-room response. It does take some software and some hardware to properly measure your room and correctly set up the PEQ. Minimum requirement is a Radio Shack SPL meter (every home theater nut should own one) and spreadsheet software (Microsoft Excel is preferred due to the ability to run spreadsheet macros).

15 cf tuned to 20hz with 500w of power and an 18hz SSF looks very good when modeled in Unibox. I would use a pair of 4" Aeroports to keep the port noise to a minimum.

-Robert

Aside from my wife listening to the radio occasionally, the most music my h/t setup plays is whatever is in the movie I'm watching. I just wasn't sure what freq was a good starting point with h/t.

I am capable of doing the resistor change, but I would definitely need to do a ton of research as I've never done that either. I'd much rather do a square or slot port if possible, I don't mind making the enclosure pretty big as I'll be turning it into a piece of furniture when I'm done. If I could change the resistor to set the ssf at 10hz, would a 12hz tune be better at that point?

I'm much more of a car audio enthusiast, so the 129.9 cutoff point of the spl meter you mentioned never appealed to me much, but I'll have to invest in one for this if it's worth it. I have a buddy with a termlab, would that be better or equal in this situation?

So at this point it is settled that I will go with the Dayton amp and the SSD with copper coils.

Thanks with the help so far guys, like I said, I'm fresh meat when it comes to the home theater.

[Robert_J 0]

I am capable of doing the resistor change, but I would definitely need to do a ton of research as I've never done that either. I'd much rather do a square or slot port if possible, I don't mind making the enclosure pretty big as I'll be turning it into a piece of furniture when I'm done. If I could change the resistor to set the ssf at 10hz, would a 12hz tune be better at that point?

I'm much more of a car audio enthusiast, so the 129.9 cutoff point of the spl meter you mentioned never appealed to me much, but I'll have to invest in one for this if it's worth it. I have a buddy with a termlab, would that be better or equal in this situation?

So at this point it is settled that I will go with the Dayton amp and the SSD with copper coils.

Thanks with the help so far guys, like I said, I'm fresh meat when it comes to the home theater.

I invested in a de-solderer from Rat Shack since I have to mod 3 NHT amps that do not have adjustable gains. Or you can just heat the solder and pull the resistor out with a pair of tweezers. Both ways are extremely easy. The amps come with a sheet that details what resistors are needed for boost/cut-off frequency. You can also view them on the PE site in case you need to order resistors. I like to set my SSF a few hz below the Fb. So a 12hz Fb with a 10hz SSF is OK. In fact, with margins of error, just getting close is OK.

I've never been a fan of slot ports for many reasons. The biggest is just the finished look. Not a problem if the sub is in the trunk but if you have to look at it, the wife wants it finished. You don't see SVS, ED , Epik, Aerial Acoustics, Klipsch, Polk, etc using slot ports on their home subs. Also, using an Aeroport will allow multple tuning points. O Audio sells a BASH amp that has an adjustable SSF with settings at 15, 20 & 25 hz. You can easily recreate a multiple tune SVS sub. Just something to think about.

The Dolby standards are 120db peaks at the seating position so the Shack meter is more than adequate. It has also been compared against a calibrated mic and the correction values are widely published. It makes using it for calibration very easy. The next step up is Room EQ Wizard (free) along with a mic (Shack SPL is acceptable) to adjust a Behringer Feedback Destroyer. The BFD gives you 12 bands of PEQ as wells memories so you can store different room curves for music or movies. Termlab may be good for SPL but you have no idea if the mic is calibrated flat or not.

That may be more than enough information. You are starting off with an excellent driver and amp. Everything after this is just icing on the cake. Your proposed sub is already head and shoulders above anything available at Best Buy, Circuit City or any other big box store.

-Robert

[tejcurrent 13]

As far as appearance, the port and sub would be facing downward, and the plate amp would be countersunk under the bottom as well. Nothing would be visible. I could make interchangable ports but if I'm soldering the dayton amp to 10hz I doubt I'd want to mess with it a 2nd time

Other than looks would there be any other reason not to use a slot/kerf port?

I went to my local radio shack and they said they couldn't even order an spl meter. Would the walmart version be acceptable?

I really need some external processing, even a simple 12 band would be wonderful, but my wife thinks its too ugly Unless I can find something really easily hidden I doubt it's in the near future.

Thanks again for all the help, it's going to be a bit until I get the build underway, but this is something I've been excited about for a while.

Edited May 1, 2008 by tejcurrent

[Robert_J 0]

I would NOT put the plate amp on the bottom. Even though it does not have a heat sink on the outside, it does use the metal plate as one. The heat needs to be able to rise and that will not happen with the amp on the bottom. Mount it on the back like all other home theater sub manufacturers do.

A cylinder is the most efficient way to create an opening with the least surface area. Does that matter with a port? Maybe if you are measuring with scientific grade tools but not your ears. We can get into a long debate about surface friction but I'm not up on my fluid dynamics research. Build a slot or square or even a pentagon shaped port. I would flare both ends though. Port noise is an issue and flares do help. www.subwoofer-builder.com has a bunch of info on flaring including info on flaring slot ports.

As for the BFD being ugly, hide it. It is a set once and forget piece of equipment. I don't even think my wife has ever commented on a piece of gear other than when I get something new. I'll do the Price Is Right model hand move over it. She always replies with a fake "ooooo" "aaahhhh". I install it, program it into the Harmony remote and the system works as usual. That's what I did when I purchased an HDMI switch box. My wife did not need to know that I had switched my HR20 DVR from a component connection to an HDMI. She still hits the same button on the remote to watch it and it still works. Functionality is all that matters. As long as it integrates seamlessly into the sytem, I'm usually able to buy it. You can also look into the EQ.2 from ED. It looks more like a piece of stereo gear instead of pro gear.

Check out www.svsound.com for a Radio Shack SPL meter. They carry them along with a tutorial on subwoofer setup.

-Robert

[tejcurrent 13]

Well the enclosure will be a coffee table, so I'll have to figure something out to hide the amp then. Thanks a lot.

[ford302redneck 15]

You need a Q.

[tejcurrent 13]

I would like one, but for the price difference the SSD will do just fine. Thanks a lot though.