After hearing a fellow avs members system I want a bit more. Mainly a better tactile response from my subwoofer but some better definition is always a plus.
A little background about my system. Some things can be changed, some can't, and I think more than anything the problem is with my room. Starting with the brunt of the bass system I have a diy elemental designs 19ov.2 18" subwoofer in a 13 cubic foot enclosure tuned to 15 hz backed by an ep2500 giving it 1300 watts. Its positioned right behind my couch and gives a nice shaking effect to the couch, but not the rest of the room.

Here is where it gets tricky. My room is very hard to drive. Its carpet and padding directly over concrete. This makes "floor shaking nearly impossible without actual TNT. My room is also a good mid sized room at 4200 cubic feet. Bass is flat in room to a little below tuning at 15 hz, and spl levels are up to about 115 db at all frequencies. It can get pretty loud, but only shakes the couch. No other seat gets the effect.

On the definition side of it the receiver I have is probably to blame. My mains can be crossed as low as 60 hz, but my receiver is old and only crosses over down to 100 hz. This I can change and am planning to hopefully sooner than later. I think a lower crossover will help with this.
So back to the tactile performance, I am thinking that a raised floor is my only good choice. I don't want bass shakers. I think I could make a floor for two or three hundred bucks and that is really what I want and was wondering if its a good idea and if so is there any specific way I should go about it?

Damn you've achived apparently perfect response and completely eliminated environmental resonances for the most part and now are looking for ways to break it. We audio enthusiasts are a tweeky group. lol!

Hell, if you want broke I'll trade you my house and I'll come put up with perfection.

I'm with ugly on this one. The "shaking effect" can add to the material, but you generally only want the main seating to have this effect, the rest of the room should not respond, mechanically, to the audio.

What they said!

My gosh, I sure hope you can't get a solid concrete slab to shake! :eek:

And if you build a raised floor, anything that sits on that floor will shake. How would you keep from transmitting the floor vibration to the walls and the rest of the house? :confused:

Bad idea. Just make the couch shake.

Oh believe me, its far from perfection. The sound is a bit muddy, that's what I attribute to the high crossover. Once the new receiver is bought I will try out 60-80 hz for a crossover setting.

Perfection with me would be accomplished with a good mix of the following:

On the top end completely seemless integration with the mains.

Further down the sound spectrum a smooth upper bass that's sound is completely distinguishable as the frequency lowers.

Midbass should be tight, punchy and powerful. Feel it kicking in the chest powerful.

Lower end should be effortless, yet also powerful. At the low thirties down to twenty hz it should still be audible, but have the ability to shake the room.

Lower than 20 hz should flap your pants legs and give the sensation as very loud but distant explosions or thunder. The type that would shake your windows.

Over the entire frequency range it should be very clean sounding. No additional artifacts or distortions. Much like what you would get from a properly designed bandpass enbclosure. All you hear is bass, no speaker.

Also there should be huge headroom. The ability to play upwards of 130 db so that when reference levels of 115 db are played the sub isn't being pushed to its limit.

This would be the perfect subwoofer experience for me.

As far building the floor and keeping it separated fromthe rest of the house, I have some ideas I picked up from various places. The floor would start by isolation pads being placed on the floor with 2x4's placed on top of them. The actual floor panels would go on top of these with insulation between the 2x4's. Keep the floor separated from the wall by having a half inch to inch gap between the two.

It sounds like you need some room treatments, not more power.

You say you do not want any transducers for the 5Hz to 30Hz content, why?

Building 2" thick individual platforms JUST for all your chairs/couches with 8 or more hockey pucks used as feet underneath each chair will give you the subtle vibration you may lack.

I simply glued 3/4" plywood together to do mine, I wrapped it in black fabric, added all the hockey pucks for the feet and its perfected.

It sounds like you need some room treatments, not more power.

Not needing more power necessarily, although the added headroom would be nice. When I had my subwoofer meet a few months ago there was a wide range of subs here in my room. Ranging from $250 bic subwoofer with a single 12" driver in a ported enclosure to the diy subs with the top output performer being the re audio xxx 18" to the pro audio stuff from worx and danley including the th50 none really shook my room. The th50 hit 128 or 129 db in my room with only a few hundred watts to it and it pressurized the room nicely as well as literally moved my pants legs. I think I could make a whole wall of subs in this room and it wouldn't shake, so no amput of power would help me out other than headroom.

That's an inspiring story. I've always wanted to try some of that Danley stuff.

It sounds like you need some room treatments, not more power.

Sorry, made that last post and didn't even think about the room treatments. I have none now unless you count thick blackout curtains but those wouldn't help with the bass. What would be good bass room treatments and what exactly would they do? Would it clean the sound that much?

The danleys were great. The th50 was my favorite. Can get louder than any other single 15" I have heard and it sounds very clean. Everyone loved it at the meet. If you have the means to get one, and a wife that doesn't care if you have a huge enclosure in your room I would get one. There is one for sale now on hometheatershack. Just to give you some insight if you are not familiar with the th50, they use just 4 of the for the entire subwoofer section in an imax theater.

Wow, sounds like your house is built very well. :)

Sounds like you have a lot more expertise than me, but have you looked at the "Seismic Sofa" project over at Parts Express? It may give you the "bass shaking" feel you want without having to get a refridgerator size subwoofer. That in combination with cleaning up your crossover like you said, may be what you're looking for?

I have looked at the seismic sofa, but it uses bass shakers. I will say that while I don't like the idea of bass shakers, I am not completely against it. To do that I would need another amp and just generally more money than I want to spend. I can do the floor on my own for little money. This is still a ways off if I do it at all, but it never hurts to plan.

My house is just a starter home. I am only 30 and we have been here for 3 years. The room was a two car garage before we moved in and as soon as we moved in we had it finished. It has a utility closet and a large walk in closet. Its around 22 x 22 x 8.5. Concrete floor under the carpet and padding is just part of the concrete slab foundation.

The whole reason I am to this point is going to the other members house and hearing his system. Granted there are a lot of variables from his to mine. His room is much smaller. I am guessing 16 x 12 x 8 and he has a crawl space I think. This helps with his shaking. He has a svs 20-39 cylinder and even though its just a 12" with a smaller amp and enclosure, it really kicks in that room. To top it off it sounds a lot better. Now he does have his mains crossed at 60 hz, and his mains are much better than mine (I have athena bookshelves and I can't remember what mains he is using, but he has klipsch surrounds including the reference series tower from a few years ago with the dual 10's) so he has better low end out of his speakers than I do.

My planned course of events is probably upgrading my receiver first, then maybe more sub for headroom (if you are not familiar about the advantages of headroom find someone who has it and you will believe), and upgrade my speakers. Somewhere in there I will get a front projector.

I have athena bookshelves


Its definitely your mains, they may not be the entire problem but they are a problem. I believe your sub is just fine but you lack that punch that so many others lack too.

My planned course of events is probably upgrading my receiver first, then maybe more sub for headroom (if you are not familiar about the advantages of headroom find someone who has it and you will believe), and upgrade my speakers. Somewhere in there I will get a front projector.

Upgrade your main speakers before anything else, you should be really spending 70-80% of your $$$ on your speakers. The receivers are a dime a dozen (well they cost more but there is zero reason to over spend on them).

btw, I like buttkickers because they go down to 5Hz. I only use them for 5Hz to 25Hz and I have it dailed so that only during the most intense scenes will I feel the impact. I have them even though I have 4 15" subs in my room too. They are great when things are turned down and the subs do not shake the room.

Brandon,
My room is 18x12x8 and it does have a crawl space. The day that you visited I was using LSA1's and LCR center. The rears used on that day were RF7's. I wish that the RF7's and RC7 had been up front that day. That set up is much more dynamic for HT.

The room does not respond to the shaking as jarrod1937 eluded to. Pictures are hanging straight. The sensation is felt in the seating and often the pants legs but no wall or picture movement.

Penn, I have to agree about overspendig on reveivers. However, i would not agree that all are created equal. When I used receivers I recall that some distorted the sub more than others.

Brandon I look forward to another visit when you have the time. Maybe I will learn how to make BBQ like you.

I have heard my speakers in a very open showroom with a better receiver and I can assure you, they can be better, but the receiver made them a lot better than what I have now. My receiver is a pioneer that's probably 7 or 8 years old. I am not sure the dac's are up to todays standards and I am sure the power is lacking. Comparing to other newer receivers I have heard this one I have just doesn't cut it.

I am glad you joined the discussion Alford. I still want to try to bring my subwoofer up to your place just to see what it can do in a smaller room with no concrete floor. I am with you and Penn in thinking that its not worth spending heavily on receivers. I am looking at the onkyo 600 series. Either the new 607 or as far back as the 605. Those are in my price range and I like what they offer. Close to quoted power, clean sound, decodes the newer audio formats, has auto setup, and on screen menus.

Making decent bbq is almost just like home theater. The first taste you get is great. After that you are on a constant quest on trying to make it better. You can get in cheap, but if you want it on a big scale it can cost multi thousands of dollars. While I am in desperate need of a new smoker (the two I have now are just not cutting it) I would really like a large trailer smoker to start catering and hopefully roll that into a restaurant one day. I have a friend that has a larger smoker and we did a charity event at a UT frat house. We sold to the general public at a football game and it was great. That was the single best bbq that I have ever made and ever eaten. We had a large group from Memphis come through and eat some and they said it bested any bbq joint they have down there. That made me want to do it that much more to have a ringing endorsement like that.

Penn, I have to agree about overspendig on reveivers. However, i would not agree that all are created equal. When I used receivers I recall that some distorted the sub more than others.
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I would like to see the data on it because that doesnt make sense to me pre-outs for subs have the lowest distortion in the whole chain, meaning the subwoofer box/driver has more distortion, the amp for the sub has more distortion. Saying the sub preout from one receiver to another has more audible distortion has me wondering if you had the trim levels completely different?

I would agree that preout voltages can be different and therefore we have to set the sub trim very high which may create more distortion but I haven't found a definitive answer on that.

btw, when I say they are a dime a dozen...Im still talking about AVRs over a certain price point, the laws of dimished returns kick in hard for AVRs once we are at a certain price range after that there isnt truely much improvements.

I don't know about data to back it up, but I do remember in my car audio 130-140 db days I could tell a difference in how clean it would sound when a better line out voltage was present. I started with a pioneer head unit that out out 1.8 volts on the pre out. I moved from there to an eclipse head unit with 5 volts on the pre out and could hear a difference. It wasn't a huge difference in fact barely audible. When measured I would get 1-2 db extra with the same setup and new head unit. I don't know if this was just the voltage, but it was just that little difference that if you had two amps playing side by side with the same material and one was playing 2 db hotter and you were asked to pick blindly which you prefer, you would almost always pick the louder one.

if you had two amps playing side by side with the same material and one was playing 2 db hotter and you were asked to pick blindly which you prefer, you would almost always pick the louder one.This is a well known effect, and one of the reasons that in a blind test levels need to be matched or the louder one will always be picked as 'better'.

It is trivially easy for a receiver to swing several volts RMS as most if not all will be designed using opamps for the analogue stages so there is no reason at all for any preout, sub or otherwise, to offer any meaningful distortion at all. Unless it was incompetently designed or it was an intended effect.

This is a well known effect, and one of the reasons that in a blind test levels need to be matched or the louder one will always be picked as 'better'.

It is trivially easy for a receiver to swing several volts RMS as most if not all will be designed using opamps for the analogue stages so there is no reason at all for any preout, sub or otherwise, to offer any meaningful distortion at all. Unless it was incompetently designed or it was an intended effect.

nless

nlessAny second year EE student can read an application note and make a line level opamp stage. It is trivially easy and has been for 20 years at least.

Upgrade your main speakers before anything else, you should be really spending 70-80% of your $$$ on your speakers. The receivers are a dime a dozen (well they cost more but there is zero reason to over spend on them).



I would like to see the data on it because that doesnt make sense to me pre-outs for subs have the lowest distortion in the whole chain, meaning the subwoofer box/driver has more distortion, the amp for the sub has more distortion. Saying the sub preout from one receiver to another has more audible distortion has me wondering if you had the trim levels completely different?

I would agree that preout voltages can be different and therefore we have to set the sub trim very high which may create more distortion but I haven't found a definitive answer on that.

btw, when I say they are a dime a dozen...Im still talking about AVRs over a certain price point, the laws of dimished returns kick in hard for AVRs once we are at a certain price range after that there isnt truely much improvements.

Your first post said receivers. Now you are somewhat quantifying that. Which is it?

I do not have the review now, however a few years back some Yamaha reciivers tested high distortion from the sub out. So yes there was data fo back my statement. Can you hear distortion without reading data before listening? If not you should be satisfied with any speaker / electronics.

Your first post said receivers. Now you are somewhat quantifying that. Which is it?

I do not have the review now, however a few years back some Yamaha reciivers tested high distortion from the sub out. So yes there was data fo back my statement. Can you hear distortion without reading data before listening? If not you should be satisfied with any speaker / electronics.

Im going to quantify it ...its a blanket statement and there are always assumptions if you want the full details you have to ask ;)

As I posted before I have never seen the data on sub outs having High distortion and its less about you backing your statement and just me being very curious about it and I want to learn more.

I own 6 AVRs, 3 pre/pros currently and I have had 20 or so on the last 5 years. I have run many through my systems (1 IB array - 4 18" drivers. 2 ported 15" subs, 2 sealed subs) so I already know that its almost impossible to hear distortion at low frequencies in the first place. Room vibrations are louder then that, also Sealed subs produce WAY more distortion down at the lowest frequencies then any pre-out will in the first place so the pre-out distortion is a mute point.


What receiver had bad sub pre-outs?

I am not sure its a matter of high or low distortion, I think its a matter of the dac's signal processing. If it can convert it cleanly into a good analog signal. That's the problem I think mine has. If there were no differences in receivers then we would all have $150 receivers. A telling truth would be to measure the response in spectrum lab with just the source and the .1 channel then the same from the sub or lfe out. If there is no difference in the two they should look like a spot on match.

I am not sure its a matter of high or low distortion, I think its a matter of the dac's signal processing. If it can convert it cleanly into a good analog signal. That's the problem I think mine has. If there were no differences in receivers then we would all have $150 receivers. A telling truth would be to measure the response in spectrum lab with just the source and the .1 channel then the same from the sub or lfe out. If there is no difference in the two they should look like a spot on match.


We both know that people always want different brands so there will never just be one $150 receiver to buy. Companies also start up knowing there are people out there that pay through the nose for something exclusive even though the SQ isnt there.

Of course Im talking about the quality of $1K type AVRs here and not the cheapest Yahama V663 type brands out there. I have a stack of AVRs not even used any more, I tend to buy and test when ever I think there is something worthy of testing. Recently I picked up the Onkyo 885 and the NAD T-175 and put them both to the test vs the Denon 2809. I then put my cheap Yammy 663 back in the mix as a pre-pro.

Once we get to the level of something like the Denon 2809 with the Audyssey MultEQ XT there isnt much room left. I guess the analog,Pure or direct mode crowd will have a wide varying opinion but Im a digital guy (Dolby, HD Audio, etc) and in the digital world its processed all the same way.

I was honestly curious about the sub preouts though because I have never read about those issues existing and if they do exist its nice to know about them.

I am not sure its a matter of high or low distortion, I think its a matter of the dac's signal processing. If it can convert it cleanly into a good analog signal. That's the problem I think mine has.A DAC doesn't do any signal processing beyond conversion. If the DSP section is doing something that creates distortion (of whatever kind) then that would have had to be designed in, and what would be the purpose of this distortion? If there were no differences in receivers then we would all have $150 receivers.Most of the additional cost in receivers beyond base models are features that I suspect most people wouldn't use but allow 'value adding' so the buyer thinks they are getting more and can justify the sales price.

Im going to quantify it ...its a blanket statement and there are always assumptions if you want the full details you have to ask ;)

As I posted before I have never seen the data on sub outs having High distortion and its less about you backing your statement and just me being very curious about it and I want to learn more.

I own 6 AVRs, 3 pre/pros currently and I have had 20 or so on the last 5 years. I have run many through my systems (1 IB array - 4 18" drivers. 2 ported 15" subs, 2 sealed subs) so I already know that its almost impossible to hear distortion at low frequencies in the first place. Room vibrations are louder then that, also Sealed subs produce WAY more distortion down at the lowest frequencies then any pre-out will in the first place so the pre-out distortion is a mute point.


What receiver had bad sub pre-outs?

Penn, A few years back there were reviews that showed distortion measurements of the sub out. Not sure they even do that now. I remember Yamaha as having high distortion (can't rember model/models).
In those days I hung out at a local shop and could make myself to home in all the demo rooms. I mentioned the distortion to a salesman (friend) and he did not believe me until I showed the article to him. Those models are no longer available so it is not so relevent.

It was audible on Yamahas I used and not on others I used.

Any second year EE student can read an application note and make a line level opamp stage. It is trivially easy and has been for 20 years at least.

Receivers have been built for more than 20 years. Still the manufacturers have a long way to go. Otherwise why would the need so many updates? Maybe they are using freshmen EE's.

Receivers have been built for more than 20 years.I'd never have guessed Still the manufacturers have a long way to go. Otherwise why would the need so many updates?Are you serious? So they can continue to sell new models. Most of the 'updates' have little to do with the analogue aspect of the units, merely features that will hopefully differentiate from others. Basic analogue design, especially using opamps, which every mass market receiver does is well known and trivial to implement in a manner that any EE, student or graduated should be able to achieve simply be reading an application note. It's not hard, about the audio equivalent of an automotive engineer designing a steel wheel for a mass market car. Hell a +/-15V (most typically used) supply with a 4580 will get you 20Vpp of signal swing with very low distortion and more modern designs will better that. That is more than enough to drive any amplifier of the market that I am aware of, and certainly all domestic units.

To the OP, superchunks in the corners will help with the 80hrz and up range. They will help tame the decay times and help "tighten" up the upperbass/midrange area.
Jarrod1937 said it best "It sounds like you need some room treatments, not more power"
Most if not all room can really benefit from acoustic treatment, even if you get more capable mains the treatments will still help out a lot.

I am not familiar with superchunks. Can you or someone else explain further?

I know my room could benefit from some treatments, but I have two things working against me. #1 I have kids that might pull them down unless I could figure a way to secure them really well. #2 not sure if the wife would like big hanging fabric panels on the walls. The only way I could see it happening is if I could dress them up somehow.

Superchunks are Owens Corning 703 or ATS acoustic board like this http://www.atsacoustics.com/cat--Fiberglass-and-Mineral-Wool-Batts-and-Boards--106.html 2" thick panels 24"x48". You cut them into triangles, I did 17"x17"x24", which gives you 8 triangels per panels, and at 2" thick gives you 16" of height per panel. You stack them in the corner, I glued each panel together, and fill in the corner. The 24" wide part of the triangle faces out into the room. You can attact them to the wall using a wood frame. Cover it in acoustic transparent fabric that matches you decor and thats it. Your make a DIY of this http://www.gikacoustics.com/gik_tri_trap.html

Cost me $170, but I haven't got them covered yet. It will help your system even if you go with bigger mains and lower the cutoff of the sub. Also because it will help with nulls and boomyness the mids and highs will sound more detailed as well. I would not go any smaller than the 17x17x24s any smaller and you loose bass absorbition. Front two corners are the most important. Heres what a good superchunk setup looks like http://www.hometheatershack.com/forums/home-audio-acoustics/7758-corner-traps-finally-finished.html

Looks good. I would absolutely need some type of nice material over top of it. Problem with my room is its odd shape. Every corner is taken. There is a large built in computer desk in one corner, a beer fridge in another, two large closets in the other two corners. The corners formed by the closets have doors immediately on one side each and a space between each is where my rptv and speakers. So with all that I don't know if I could fit any corner treatments in. What about a sono tube filled with sand? Will that do any good. Saw somewhere that it helps with bass.

Being I have no experience with this I am just guessing, but this would help and upper bass gains over normal flat response and possibly help with any corner reflections if that's what they are called?

Well the sono tube isn't going to help you either. For one they are difficult to make, two there is alot of mixed reviews on if they are even useful, and three bass trapping is 99.9% effective if in the corners, floor to wall, wall to ceiling, and wall to wall. Some of the other alternatives get expensive. The only thing I can come up with right now with out seeing pics of the room would be to use the same owens corning 703 and make table bass traps http://www.gikacoustics.com/gik_elite_table.html. Instead of make triangles cut them in any shape really that you want and do a wood frame and put a top on in and put them around the room, the larger the better. Keep the frame to a minimum, and cover the opening with a fabric, muslin fabric and burlap work the best http://www.gikacoustics.com/gom_fabrics.html#build. Hope this helps, this is a big part of the solution, but going with larger mains, and lowering the crossover will help, but the "muddy" part your hearing is the bass reflections still going after the woofer has stopped. If you have the time to learn it Room EQ Wizard is very helpful, but its a pain in the a$$ to get working, it can tell you the best place to put the sub, were the best place is to put the treatments.

I've tried messing with REW with no luck. I need to have a nice quiet kid free afternoon to sit down and mess with it for hours to get it right. I've plotted using my spl meter once and the correction files that go along with it don't seem correct. Using sine waves I was all over the board but mostly down low it really jumped up. I was up as much as +12 db when averaged to 85 db down at 10 hz and then at 15 hz (my tuning frequency) it actually went down to +8. Maybe the correction files I used were wrong.

Here is a plot from my sub meet I had in april.
http://www.avsforum.com/avs-vb/attachment.php?attachmentid=140362&d=1240278712

My sub is the light green line in the middle graph. If you can see it tracks pretty level all the way across compared to the other subs. Keep in mind these were all played at the same location and it wasn't the most ideal location. Just the best spot for all the very large subwoofers (including the huge Danley TH-50).

If I can find a decent spot for one of those tables I may try to build one if I can find plans or if you know how to DIY them.