DIY newbie looking at subwoofer options

[ajpoe]

0 dB is all the way to the right. I have it 3 clicks less on each channel which puts it at 1 dB. At 0 dB I noticed the K1 reach the clip lights a couple times, but at 1 that doesn't happen ever.

From right to left the increments go 0, 1, 3, 5, etc. until you get to 21, 25, 30, 45, 100 on the far left.

I guess there must be quite a bit of extra bass added beyond the LFE being 3 dB hotter on the DTS track because from -3 to +6 in my receiver is a 9 dB difference. I never noticed such a differnce with my old powered subs, but then again, they weren't in the same league as these.

[SteveCallas]

Ok, mine is the same way, starts high on the left, drops to 0 on the right. So I guess I'll do my initial testing somewhere between 0 and 3. You said you had to adjust your processor from +6 to -3...if you dropped your normal DD level a little lower than +6, I assume you can get away with going full 0 on your amp and no clipping? I've read that you want your sub level in the processor as low as possible to prevent distortion - at the same time, I realize that pro amps aren't at the same sensitivity as most processors.

+6 to -3 is a big difference. You said you had to do it to prevent the BFD from clipping, but how do the realtive levels of bass sound to you? Does the bass in DTS at -3 sound as loud and powerful as the bass in DD at +6?

I know there used to be an issue when DTS first came out of some receivers not having the +10db adjustment for DTS LFE levels, which would make the LFE in DTS almost non existant unless you cranked up the sub level, maybe your processor has overcompensated LFE levels for DTS? I dunno, just taking a wild guess. What are you using for processing?

[ajpoe]

My processor is a Rotel 1068. I didn't adjust the DTS from +6 to -3. I had everything at 0 and set the BFD to BYPASS so I could measure the input levels. At 0 in the sub setup of the 1068 for DTS, the BFD was still getting into the red quite a bit while playing a DTS track. I had to drop it back to -3 from 0. However, for DD, I wasn't getting near the red for input and the bass was weaker to my ears so I was able to boost DD sub output to +6. The 9 dB difference I was talking about was between DTS and DD. When watching movies now, both DTS and DD sound very similar to me in bass production... I'll check some other movies for comparison.

I just had no idea DTS was so much hotter in the bass regions because I never experienced anything like this with my old powered subs. The sub levels in my 1068 were set to 0 for DTS, DD, Music... everything.

My current sub output settings are +6 for DD, -3 for DTS, +8 for DPLII and +6 for Stereo/MPEG. I don't use any of the other outputs so they are left at 0.

[SteveCallas]

Ok, one more question. Aside from the bass, is the spl from the speakers about the same with DD and DTS using constant channel levels for your speakers? It is close enough that it's negligible? If they are, then I would have to assume it is some kind of incarnation of the old DTS 10db LFE problem.

[ajpoe]

When I watch a DD movie, my volume knob is usually around 74 or 75 and when I watch a movie that is DTS, my volume usually ranges from 70-72. This gives me about the same volume from the mains and after making my adjustments to the sub out, the bass and mains sound about the same while watching at those volume levels.

[SteveCallas]

Hmm, so you have to lower the volume a bit, plus lower the sub level as well. That definitely sounds like some kind of error with the DTS LFE level in the processor. Nothing major though, as long as you already know what levels to set them at (+6 and -3), you're fine. I just figured that by now, all processors had this thing resolved.

[ajpoe]

After more listening/testing, I have moved DD, PLII, and Stereo/MPEG up to +7 dB and DTS is still at -3 dB. I guess that accounts for the -10 LFE issue you speak of. Maybe some of the Rotel or other experts can give some input on this as well.

I also decided to add the grills to my boxes. I had to get a little creative since I didn't recess the driver, but I think they look nicer in my living room with the grills on so I went for it. Basically, I used 48 of these super strong neodymium magnets. I superglued 1 inside each hole in the subwoofer box and cut off the plugs from the grill to super glue 1 to each of those locations as well. I added 4 more stacked in between them to give me 6 high at each location. Now my grill is suspended about 3/4" or more off the box and the drivers do not ever touch them. I think it looks pretty cool too! I checked some high excursion scenes and I get no vibration, movement or noise from the magnets or grill while playing. Here are some crappy photos from my new phone's digicamera:

[ThomasW]

That's a pretty clever solution to the problem ..... :T

[SteveCallas]

Yeah, my old receiver has the opposite problem, the DTS LFE is 10db too low - not really a problem, just an annoyance. I plan on getting Pioneer 1015 this month - seperates are out of my league right now, just out of college. With my amp at 3, and a quick calibration, my sub sounds about right at -8. I credit this to the high sensitivity of the carvin amp, it's 1 volt.

[Andrew Pratt]

I used those neo magnets to hold my grills on as well...much better then the plastic plugs as there's no indication they're there when you remove the grills :T

[Pieter]

Stylish, Anthony.

[Dennis H]

After more listening/testing, I have moved DD, PLII, and Stereo/MPEG up to +7 dB and DTS is still at -3 dB. I guess that accounts for the -10 LFE issue you speak of. Maybe some of the Rotel or other experts can give some input on this as well.

Yeah, DTS is mucked up. Dolby is standardized; the LFE track is recorded 10dB low to give more digital headroom on the disk and the prepro provides a 10dB boost. Some DTS disks record the LFE track 10dB low, like Dolby, and some don't. Many prepros and receivers have a menu setting for the DTS LFE level but the Rotel doesn't appear to have that so your only option is to set the sub level like you are doing. The bad thing about doing it that way is you are adjusting the level of the bass redirected from small speakers as well as the LFE level. But we do what we need to do to get it sounding right.

[ajpoe]

Well, I just thought I'd post an update. I spoke with a couple Rotel experts and they said that I shouldn't have to account for this DTS issue in the processor. I checked some other DTS and DD movies and it looks like every movie is just recorded differently... which I knew, just never noticed such a variance with my old subs. After setting my controls as described in the previous post, I watched the Apollo 13 blastoff in DTS and it was very weak. So that -3 dB on DTS really hurt with that movie. Then I put in the glass tapping scene in Finding Nemo (DD) and at +7 for DD it was too much! The experts are right... there isn't really this 10 dB DTS issue in the Rotel after all. I set everything back to 0 and calibrated with AVIA and watched Assault on Precinct 13 in DTS and it sounded great... but last night I watched the Sahara in DD and the low end was really really weak. So weak that I threw Finding Nemo (DD) back in to test. I listened to a few scenes including the glass tapping and it still sounded great. I'm leaving everything at 0 dB. I was told the easiest way to account for the variances was to use the temporary adjustment of the Sub Out on the remote so I don't have to go into the OSD each time... plus it will reset after I turn off the processor.

[SteveCallas]

So basically, with more than capable subs, there isn't going to be much of a benefit of calibrating them to your other speakers? That doesn't sound too cool, I don't want to have to try and figure out what to set my sub level to for every movie.

You said you are going to try leaving the sub level at 0 when possible. How does 0 compare to the levels of the other speakers? Is the sub equal to, or a little hotter than the other speakers at 0?

[ajpoe]

Yes, after calibrating with AVIA, most movies should sound their best. With AVIA, the sub is slightly hotter than the other speakers. I think I set the mains to 75 and the sub was around 78 or 79. When I ran the LFE sweep, I hit up to 82 at times, especially where I added the bump in my house curve.

Some DTS movies are going to run hot in the LFE, which I don't mind having the extra bass. But, I do mind when the track is really weak in the LFE. In the few instances when that happens, I can use the remote to temporarily bump up the sub out without having to change any of my settings in the OSD. After recalibrating with everything at 0 dB, most movies I have watched or tested have sound good. Sahara just happened to be one that was really weak in the low end... which did suprise me because it's a new movie and some of the scenes seemed like they should be more powerful. If anyone else has this movie, maybe they can confirm it for me.

[ajpoe]

Ok, I'm back in town and got RoomEQ Wizard up and running. I put a splitter on the single line out of the sound card and ran it into left and right analog inputs on my 1068.

I ran a sweep on the subs with and without the filters of the BFD active and the mains turned off. The sweep with the filters looks like I have them set up correctly. Maybe you guys can add some insight. I also ran full range sweeps with the subs and mains on in both stereo and DPLII modes. If you guys see anything that needs to be addressed, please le me know.

[Shane Martin]

I'm going to bump this because I'm extremely intrigued and I think I can do this w/o major help of my local friends.

Essentially you took the existing PE boxes and added to them correct? This would be fairly easy for me because I wouldn't have to be building boxes. I have access to the basic tools to make this part happen.

The problem will be the drivers. I'm pretty sure I won't have the luxury of the avalanche drivers which are now gone. What driver replacements would work?

ThomasW, if you are following this, would this combo get me where I want to be or close given my other thread at HTT? I'm thinking so...

As far as an amp goes, I can find a crown locally thru a shop.

ThomasW, thoughts?

Ajpoe, I appreciate what work you have done and this thread because this actually gives me hope that I can do this. I am the true definiton of a DIY noob.

[ajpoe]

I bought the PE boxes and a sheet of mdf and some glue as thomas recommended. I used a jig saw and circular saw to do all of my cutting and layered the whole inside with a 2nd layer of mdf and added the extra bracing. You can still get avalanche drivers, they will just be the new ones and $75 more than the closeouts were. Watch for a K1 on Audiogon as it's a great amp. I honestly have never heard anything it and don't see myself ever changing subs unless I did an upgraded DIY project in a dedicated room down the road.

[ThomasW]

Shane,

This is certainly a viable option. The drivers to use would be the SoundSplinter RL-p 15"s, they are VERY good drivers.

[Shane Martin]

How would they compare to the Avalanches(the old ones)? I would assume the newer ones will be close or better.

What I need to do is learn what these specs mean before I jump further(I think).

[Scott Simonian]

You can still get avalanche drivers, they will just be the new ones and $75 more than the closeouts were.

How do you go about doing that? I thought all the old ones were gone and that the new ones weren't finished yet.

[ThomasW]

Shane,

If you want to learn about T/S parameters fine, or you can just trust my recommendations .... :wink:

They are a VERY good driver, aluminum cone, double spiders, monster motor. Easily as good, probably better than the Ave units, and priced accordingly.....

The SS drivers are made by TC-Sounds. The same people that are going to make the new Ascendant drivers, and that make the high performance drivers SVS uses.. :T

[Shane Martin]

From looking at the SS site, I see they have either dual 4 ohm voil coils and a dual 2 ohm voil coil setup. Which would I be looking at?

I guess it's best to buy direct. It looks like they are cheaper than going thru Kyle at Acoustic Visions.

[Bent]

I've ordered a daul 4 ohm 15" RL-P from Kyle - my ADA 1200 will provide 600 watts to it at 8 ohms.

[ThomasW]

I see they have either dual 4 ohm voil coils and a dual 2 ohm voil coil setup. Which would I be looking at?

Depends on whether you're going to use one or two drivers.

[Shane Martin]

I would do 1 per box. 2 boxes total. They would be "stacked" sitting next to each other in my front left corner. I can't go the same way AjPoe did because I have a huge null in the other corner.

[Bent]

Well a Crown amp shouldn't have any truble with a 4 ohm/channel load - but it's not my call.

(I'd get the dual 2 ohm in this case though...)

[MDJones]

Hmmm, that's strange. When I ordered my Rl-p 15" a couple of weeks ago, I swear there was no 2 ohm voice coil option... The 12" had both options available, but not the 15".

[kidkj2000]

did you build your subwoofer?

I read the thread and wondered if you ever built it?

Just curious, I thought that it'd be kewl if you had some pictures.

Thanks!!!

[ThomasW]

You might want to reread page 5 of the thread....