Hey guys,
I have been doing alot of research into speaker design and implementation.
It seems to me that the best way to get the greatest dynamics is to have a system that can accomplish the highest SPL with as little power as possible.
However, It seems to me that this can be difficult as you start to dig deeper in the frequency range. Tapped Horns can be difficult to build, LLT are well....Large(too large for many that are working with a small-medium family room), and Sealed subs are less efficient.
Right now I am working with a PC12-NSD from SVS and it is a pretty good subwoofer. however, I will say that I wish it went deeper/louder than what it does.
The PC12 is pretty much the largest that can go where the sub is located so LLT is really out of the question. To get a TH I would need something the size of a refrigerator, and a sealed sub, even though it can dig deeper, wont play as loud.
So I am curious to know how much SPL is really needed for movies in those lower registers?
The best compromise that I have found is a Passive Radiator. Even though they are more expensive they often provide the highest WAF with the greatest performance. I could possibly even build something more along the lines of what an LLT PR design would be like. Granted this would cost a significant amount more than a well designed bass reflex but it seems like on of my best options. However, I could tune it as low as possible with a high pass filter and get some good results.
That being said, there is also the option of a smaller tapped horn that is not tuned as low that can get some higher SPL in its frequency range.
So once again, I get confused as to the best option is to have High enough SPL for movies across the frequency range that is needed.
Some argue that you wont even miss anything below 30hz as long as the 30hz can play loud enough.
What is everyone else's take on this?
How low is really needed and how much SPL is ideal for the home environment?
I have been doing alot of research into speaker design and implementation.
It seems to me that the best way to get the greatest dynamics is to have a system that can accomplish the highest SPL with as little power as possible.
However, It seems to me that this can be difficult as you start to dig deeper in the frequency range. Tapped Horns can be difficult to build, LLT are well....Large(too large for many that are working with a small-medium family room), and Sealed subs are less efficient.
Right now I am working with a PC12-NSD from SVS and it is a pretty good subwoofer. however, I will say that I wish it went deeper/louder than what it does.
The PC12 is pretty much the largest that can go where the sub is located so LLT is really out of the question. To get a TH I would need something the size of a refrigerator, and a sealed sub, even though it can dig deeper, wont play as loud.
So I am curious to know how much SPL is really needed for movies in those lower registers?
The best compromise that I have found is a Passive Radiator. Even though they are more expensive they often provide the highest WAF with the greatest performance. I could possibly even build something more along the lines of what an LLT PR design would be like. Granted this would cost a significant amount more than a well designed bass reflex but it seems like on of my best options. However, I could tune it as low as possible with a high pass filter and get some good results.
That being said, there is also the option of a smaller tapped horn that is not tuned as low that can get some higher SPL in its frequency range.
So once again, I get confused as to the best option is to have High enough SPL for movies across the frequency range that is needed.
Some argue that you wont even miss anything below 30hz as long as the 30hz can play loud enough.
What is everyone else's take on this?
How low is really needed and how much SPL is ideal for the home environment?
yes, but since when you have an efficient design you dont have to feed the system as much power which also means less power compression...leads to less distortion...
aslo, I consider any well implemented XO to be time aligned....which is why, even though it is part of the problem, I didnt include it. My apologize for not being clear about that earlier.
aslo, I consider any well implemented XO to be time aligned....which is why, even though it is part of the problem, I didnt include it. My apologize for not being clear about that earlier.
Your sub should be up to the job. I think your spl problem may lie with your subwoofer placement. Your room dimensions may be producing nulls at your listening position. Try a different sub location if you haven't already. If WAF is important, you may have to move it to the ideal location only when watching movies.
A better fix (but with no better WAF) is to use multiple small subwoofers, ideally one at each corner of the room to force out all the standing waves. This idea was pioneered by the R&D people at Harman Industries, who have done a lot of research in this area.
Anyway, I would recommend you take a look at this white paper from Harman to get an idea of how to get around problems with bass reproduction, available at:
http://www.harman.com/EN-US/OurCompany/Innovation/Documents/White%20Papers/LoudspeakersandRoomsPt3.pdf
A better fix (but with no better WAF) is to use multiple small subwoofers, ideally one at each corner of the room to force out all the standing waves. This idea was pioneered by the R&D people at Harman Industries, who have done a lot of research in this area.
Anyway, I would recommend you take a look at this white paper from Harman to get an idea of how to get around problems with bass reproduction, available at:
http://www.harman.com/EN-US/OurCompany/Innovation/Documents/White%20Papers/LoudspeakersandRoomsPt3.pdf
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THX, etc., reference is 115 dB/20 Hz at the LP for the LFE channel and considerably more is bass management is used to redirect the other channels to the LFE, so may need to be even somewhat more if room gain doesn't make up for the loss over distance.
There are no specs for < 20 Hz AFAIK, so it's really up to the individual's budget, room construction and any neighbor issues for how loud to design for in the infrasonic BW.
Whoever said this apparently has never experienced a good infrasonic system with a soundtrack that challenges it.
A rectangular cab that takes up the area, height of the SVS will be plenty large enough for [4] Peerless 830500 sub-woofers in a bipolar sealed alignment and with a bit of room gain it should yield a very high SQ down into the single digits plus be close enough/meet THX reference if there's at least 1.2 kW of clean power on tap.
Whether your house can take this amount of punishment remains to be seen though. I wrecked mine with quad 15" with PRs tuned to 14 Hz/1 kW from just watching one movie at reference [U-571] and listening to one pipe organ symphony CD at the same SPL as the one I've measured at a local church, neither of which has the output/BW of numerous current movies.
GM
Actually the best dynamics come from listening only to recorded music that has not been compressed at all (loudness, not bit rate).
It's a suspended ['floating'] floor, lapboard siding construction on a concrete block foundation and apparently the house has a ~14-18 Hz Fs as it vibrated hard enough to bust virtually all the sheet rock joints and 'rained' the ceiling down on us in the open layout living room where the system is, causing enough damage to the adjoining rooms to require all new ceilings in ~half the house.
Fortunately, none of the stuff stored up there fell through and the original sheet rock was only 3/8” thick and so old [1952] it just crumbled, so other than the shock of it, being covered in ~ 6” of blown in rock wool insulation with all the choking dust this implies was the worst of it for us.
Worse, it shattered one of the floor's concrete block pilings supporting the tie beams between the front/rear floor joists. This caused the main roof support to sag, buckling load bearing walls, damaging some water pipes, wiring, the list just goes on and on.
This happened in 2000 and while I quickly got all the major stuff repaired 'good enough' to feel secure living here, circumstances since then has forced me to do all the other repairs at a snail's pace and still probably years away from completion unless the economy does a major rebound real soon since insurance not only doesn't cover any of it, they charge me a ‘penalty’ each year for its unfinished looking condition.
GM
Here's an interesting fact about subwoofer power compression.
When an inefficient driver is played at a given spl, it's voice coil tends to run hotter than that of a more efficient driver. Its resistance will increase with temperature. When the coil heats up, the added resistance raises the Qes of the driver, making it less efficient. Therefore, if there are say, a series of explosions on a movie, the VC will heat up and the explosions will become slightly less loud. If the bass comes less frequently, VC temperature will not rise as much and the volume of the bass notes will be more accurate. This is the downside to using a tiny or inefficient sub with more efficient satellites. I don't believe there is any way to compensate for this besides having better VC cooling.
yep, power compression is one of the biggest culprits in my eyes of bad audio reproduction.
I can honestly say that I dont understand why so many people want enough power running to their speakers and subs to power half of new york city(exagerating but you get the point)
with speakers that are 95db 1w/1m sensitive you can get something like 100db with only 50 watts of power.
I plan to build some F5 v2 Turbo amps to drive my mains which can do something like 72watts....so I wont be hurting for volume...
Now with a subwoofer, from what I understand, you get the majority of the output from the first 100watts of power. So after that, half of what you are fighting is power compression. So, in my eyes atleast, I would much rather get a sub design that can produce high enough SPL in those first 100 watts that I would have 1-200 watts of overhead from a 200-300watt amp.
I can honestly say that I dont understand why so many people want enough power running to their speakers and subs to power half of new york city(exagerating but you get the point)
with speakers that are 95db 1w/1m sensitive you can get something like 100db with only 50 watts of power.
I plan to build some F5 v2 Turbo amps to drive my mains which can do something like 72watts....so I wont be hurting for volume...
Now with a subwoofer, from what I understand, you get the majority of the output from the first 100watts of power. So after that, half of what you are fighting is power compression. So, in my eyes atleast, I would much rather get a sub design that can produce high enough SPL in those first 100 watts that I would have 1-200 watts of overhead from a 200-300watt amp.
I suggest that people thinking of themal compression being a great problem should build an apparatus which can measure the voice-coil temperature in real time during their listening sessions.
If found not to be negligible, it can been rid of by using feedback with an acceleration or a velocity (secondary voice-coil) sensor
By the way, it is at low frequencies that the excursion of the cone is the greatest and then voice-coil is best cooled.
If found not to be negligible, it can been rid of by using feedback with an acceleration or a velocity (secondary voice-coil) sensor
By the way, it is at low frequencies that the excursion of the cone is the greatest and then voice-coil is best cooled.
WAF
Wife Acceptance Factor!
Jeez, 'bout time this was dealt with. If you're on a site like this, your dedicated to your audio, yeah, you're an Audiophile. How about you tell your wife exactly what you need and what you intend to do, also tell her that you will try and fit your sub in line with the decor of your home, that your wife and yourself own. If she doesn't appreciate your love of how your system should sound to you, tough. If you got to build it big and solid, make it look like it blends in with the decor, best you can. Nobody stopped loving someone because they had a huge SUB! Your love for your system is a part of you, she should agree to that. When its built, sit her on it and play a 120hz test tone, she might love your sub too 🙂
Apologies in advance, Mods
Mike
Wife Acceptance Factor!
Jeez, 'bout time this was dealt with. If you're on a site like this, your dedicated to your audio, yeah, you're an Audiophile. How about you tell your wife exactly what you need and what you intend to do, also tell her that you will try and fit your sub in line with the decor of your home, that your wife and yourself own. If she doesn't appreciate your love of how your system should sound to you, tough. If you got to build it big and solid, make it look like it blends in with the decor, best you can. Nobody stopped loving someone because they had a huge SUB! Your love for your system is a part of you, she should agree to that. When its built, sit her on it and play a 120hz test tone, she might love your sub too 🙂
Apologies in advance, Mods
Mike
Heheh! I completely agree, and so does my wife, I just read your post to her, she chuckled at the last part though. When my subs clear coat are finished we'll give it a rumble 😛
... The tough part is finding any baby sitters for our 20 months and 3,5months old daughters.
Frequencies
I heard that ladies toys vibrate around the 120hz region and that that pea sized organ down below has a resonant frequency of 33hz! I think if the WAF can be overcome its got to be along those lines, yeah?
For some reason, ladies tend to turn up the volume on Flat Erics tune, remember him?
Flat Eric in Levi's Ad - YouTube
Anyways, regardless of that, you cannot change the laws of physics, build it big, and bass will come.
Mike
I heard that ladies toys vibrate around the 120hz region and that that pea sized organ down below has a resonant frequency of 33hz! I think if the WAF can be overcome its got to be along those lines, yeah?
For some reason, ladies tend to turn up the volume on Flat Erics tune, remember him?
Flat Eric in Levi's Ad - YouTube
Anyways, regardless of that, you cannot change the laws of physics, build it big, and bass will come.
Mike
Hah! Maybe I'll go for 66hz pressure induced dizziness then 😛
120 may be too high for my sub.
Like I said in another thread, my wife objected when I told her I am getting rid of my ~300L TH. I use it as a tv and stereo bench, works as a speaker stand too. 244cm long.
HAHAHAHAHA!
I am restricted by the room just as much as I am by my wife.
I know that subs are omni-directional but I was considering taking the PC12-NSD apart and just make a box that is front firing compared to downward firing to try and "aim" it to see what that does in regards to the nulls in the room.
BTW, it may be worth noting that the pc12-nsd that I have is the older version that has the BASH amp
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OK Mike, some of us must be curious as to how the research was accomplished to determine that 33Hz spec - and whether it applies to all
But further discussion along these lines could very easily transcend the boundaries of decorum that we'd like to maintain.
But further discussion along these lines could very easily transcend the boundaries of decorum that we'd like to maintain.
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