Hi All,
I've noticed that many home theatres feature beefy tower speakers, centre channels, and surround speakers (like the SVS Prime Series), capable of reaching as low as 30hz or even lower. These setups are often paired with high-output subwoofers covering the 20-100hz range.
In a theatre setting, dynamics play a crucial role. Sounds range from quiet whispers to intense explosions, gunshots, and dramatic music. It's essential to capture this range effectively.
Another point to consider is the low-performance amplifiers in most AV receivers compared to high-fidelity, two-channel amplifiers. The former typically falls short in handling low frequencies as effectively as a quality subwoofer amp or plate amp. They also struggle to drive low-efficiency tower speakers to high SPLs and don't love <8ohm loads.
Instead of hifi woofers, which sacrifice sensitivity and dynamic range for low-frequency extension, wouldn't PA-style woofers be a better fit? Furthermore, should we consider using compression drivers in short, wide directivity waveguides instead of dome tweeters on flat baffles?
I'm thinking along the lines of a combination like the SB 34CD-PK with the 6MW150D or 8MWN150 in a two or 2.5-way reflex box. You could add a midrange driver if you want to get fancy, although the specific driver isn't crucial to this discussion; it's more about the design philosophy.
The use of PA drivers could add ~6-10dB more sensitivity while not compromising bass due to the presence of a subwoofer(s).
What do you think, am I looking at this wrong?
I've noticed that many home theatres feature beefy tower speakers, centre channels, and surround speakers (like the SVS Prime Series), capable of reaching as low as 30hz or even lower. These setups are often paired with high-output subwoofers covering the 20-100hz range.
In a theatre setting, dynamics play a crucial role. Sounds range from quiet whispers to intense explosions, gunshots, and dramatic music. It's essential to capture this range effectively.
Another point to consider is the low-performance amplifiers in most AV receivers compared to high-fidelity, two-channel amplifiers. The former typically falls short in handling low frequencies as effectively as a quality subwoofer amp or plate amp. They also struggle to drive low-efficiency tower speakers to high SPLs and don't love <8ohm loads.
Instead of hifi woofers, which sacrifice sensitivity and dynamic range for low-frequency extension, wouldn't PA-style woofers be a better fit? Furthermore, should we consider using compression drivers in short, wide directivity waveguides instead of dome tweeters on flat baffles?
I'm thinking along the lines of a combination like the SB 34CD-PK with the 6MW150D or 8MWN150 in a two or 2.5-way reflex box. You could add a midrange driver if you want to get fancy, although the specific driver isn't crucial to this discussion; it's more about the design philosophy.
The use of PA drivers could add ~6-10dB more sensitivity while not compromising bass due to the presence of a subwoofer(s).
What do you think, am I looking at this wrong?
Sounds like Earl Geddes' approach, but he used bigger pro woofers (12 - 15") and waveguides to match. His aim was to control directivity to as low a frequency as possible to minimize early reflections from the sidewalls. Add multiple subs to fill in and even out the bottom end.
I’ll stick my neck out and say that I find that the modern releases have too much dynamic range, hearing-damage levels. I find it a common complaint that people have to ride the volume control, and the compressors don’t seem very good at levelling it out. The way they master the films doesn’t sound natural at all, and the bass often centers somewhere around 45Hz.
If there is any point in covering the lowest registers, I’m not sure. Seems most films don’t touch nearly as deep as what’s found in video games and music with electronic bass.
Honestly though, my next speaker build is going to be SQ-focused but will likely use pro woofers for the sensitivity and longevity.
If there is any point in covering the lowest registers, I’m not sure. Seems most films don’t touch nearly as deep as what’s found in video games and music with electronic bass.
Honestly though, my next speaker build is going to be SQ-focused but will likely use pro woofers for the sensitivity and longevity.
These do not play down to 30Hz. There's often a crossover to the subs, typically occuring around 80Hz-120Hz.
This dynamic range is often smaller due to the background noise that exists.
Most AVRs have 'decent' amplifiers doing 50W per channel or so and it is important to stay within this limit, in order to make good use of the AVR. For a theatrical crest factor of 20db (100x), the average power for an AVR-based system would be around 0.5W per channel.
Possibly, but there're more tower speakers than AVRs that themselves struggle to reach the high SPLs.
Yes, they might be a better fit in some situations. Unfortunately, the 'hi-fi' market has managed to create a hype that prevents scientific thinking altogether. However, it is also necessary to look into the 'PA-style woofer' before making such conclusions.
Yes, but the possibility of compression drivers arises from their efficiency, as wider is generally considered better (easier to EQ off-axis) when it comes to directivity. Further, there're people who use compression drivers without horns, facing backwards (front end closed) just like a dome tweeter.
Well, balance in all things, particularly performance. When you're young, this get your bones knocked about stuff is fun, but with age, that can change. Coming up on 70, I'm finding I prefer a lighter touch of an OBs velocity wave, versus a sub's pressure wave. Some wouldnt even consider that bass at all...
That's just me. Others my age I've heard have the bass- shakers on every seat, with racks of 19" mount amps to drive them all; and that's just the seating part of their theater.
I suppose one could take it to the automotive sound competition level, where you cant even be in the cab when the system is playing at performance goal levels.
Someone will buy themselves an Unholtz-Dickie shaker, mount it to the cement floor in the basement, run a pylon up to the bottom of the living room floor and be able to pop the sofa right up off the carpet - with 4 people going for the ride.
;')
Some things come at a VERY HIGH PRICE !
https://www.google.com/search?q=inf...BGI4FmAMAkgcEMi0xMKAH4lM&sclient=gws-wiz#ip=1
https://www.google.com/search?q=inf...BGI4FmAMAkgcEMi0xMKAH4lM&sclient=gws-wiz#ip=1
For a domestic environment in a medium size room most speakers will do the job and I set all speakers to small no matter their size and direct LFE channel to the sub with 60Hz xo. For music I use a different pattern where the LR are large and share the bass with the sub. For larger rooms with insane dynamics and volumes there would be different requirements.
Being an old fart over 70 I prefer a more gentle approach with good clarity and not be be dominated by bass.
Being an old fart over 70 I prefer a more gentle approach with good clarity and not be be dominated by bass.
Not at all. If you can install a proper foundational bass and sub bass system first, what happens above 100hz can be much more efficient and dynamic…….LF extension is the grunt…..and consumes most of the power.
Three subwoofers minimum……4 being much better.…..combined producing an F3 to 25hz on paper which will look more like 20hz in room with gain. Target 90db with 100db dynamic peaks.
How large, efficient and expensive will depend on the size of your room.
Hifi dome tweeters vs Pro compression drivers is a whole different discussion………there’s some tonal differences there that modern measuring methods and gear can’t show but our ears do. This being said……better made ‘hifi’ tweeters…..domes, true ribbons and AMTs can be found in the 90-95db efficiency range……it’s the midwoofers that can’t keep up……and in the case of pro audio, surface area still rules here whether it 12” drivers of multiples of smaller.
I would overall agree with your assessment……your main channels don‘t require an F3 below 80hz……which can result in more efficient designs………but how you handle the lower frequencies still matters for 2 channel music matters. I’m a live/recording engineer by trade so I can say with full confidence that not all sub 100hz content is mixed down to mono.…..and with today’s modern synth instruments we can often find true left and right separation down to 60hz. This can create a real problem for those who rely on HT systems to also perform let’s say for lack of a better word ‘hifi’ 2 channel music reproduction.
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I think you seeing very right @citizen sc. Then Im not very demanding when it comes to movie sound. -I value music reproduction much higher and most movies contains a lot of music too. Speech intelli? is of course also very high on the list when watching anything on a screen.
I had a wow-experience when I got a HiFi-stereo VCR and we saw Waterworld on my friends Dali 3:
Before that I only knew the sound from some good CRT TVs. They are modest, very good for the price speakers, but I haven't heard such a jump in fidelity and enjoyment since, when it comes to the audio side of movie watching.
You are right. -Building or buying HT or stereo speakers that goes down in the 30ies Hz when aided by a sub anyways, is of course wasted efforts, that could be spend on higher fidelity like dynamics.
The general AVRs dont have good amplification. That's true, and one would have to find its review on an objective site like audiosciencereview to judge it. I think 6ohms is generally fine for an AVR, but only if its minimum impedance, which is mostly unknown to speaker owners 😊.
Dinamics are if course of importance. For the outmost sublime experience a system has to deliver the peaks that we know music and effects contains (30db?).
Half of that will still let us thoroughly enjoy a movie, so its a ballance where the designer has to consider the demands of the taget consumer between loudness, frequency response, directivity, dynamics etc.
When I was into subwoofers it always bugged me, that reviewers and brands are so focused on how much bass can be pulled out of of a small speaker, when they could just go a little bigger or disregard it, since a sub would handle it and sum better without a boost in mains speakers.
You should be head of design with your approach 😊
Cheers!
I had a wow-experience when I got a HiFi-stereo VCR and we saw Waterworld on my friends Dali 3:
Before that I only knew the sound from some good CRT TVs. They are modest, very good for the price speakers, but I haven't heard such a jump in fidelity and enjoyment since, when it comes to the audio side of movie watching.
You are right. -Building or buying HT or stereo speakers that goes down in the 30ies Hz when aided by a sub anyways, is of course wasted efforts, that could be spend on higher fidelity like dynamics.
The general AVRs dont have good amplification. That's true, and one would have to find its review on an objective site like audiosciencereview to judge it. I think 6ohms is generally fine for an AVR, but only if its minimum impedance, which is mostly unknown to speaker owners 😊.
Dinamics are if course of importance. For the outmost sublime experience a system has to deliver the peaks that we know music and effects contains (30db?).
Half of that will still let us thoroughly enjoy a movie, so its a ballance where the designer has to consider the demands of the taget consumer between loudness, frequency response, directivity, dynamics etc.
When I was into subwoofers it always bugged me, that reviewers and brands are so focused on how much bass can be pulled out of of a small speaker, when they could just go a little bigger or disregard it, since a sub would handle it and sum better without a boost in mains speakers.
You should be head of design with your approach 😊
Cheers!
You are right, but one can still enjoy organ and double bass, when it comes out of a transistor radio, so case kind of reopened😊
You can even enjoy an action movie, when having to settle with a better phones build-inn speakers. Preferably stereo 😄
Cheers!
Oh. Btw I remember a couple of Denon AVRs measuring very good on ASR.
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Hi,
Very fundamental stuff for any speaker project. First thing should be to calculate how much SPL capability one needs for given application. Failing to do this makes underwhelming system.
For example for home theatre, perhaps assume 85dB sound level at listening spot + 15dB for dynamics, or if there is a standard you want to follow, take numbers from that one. Now, just calculate what this means in your place with listening distance. It could be complicated if everything is accounted like small room acoustics, but it shouldn't as oversizing is always fine and avoiding undersizing is why you do the calculation in first place. What I mean by undersizing is that it's not problem to reproduce 100dB of treble, but 100dB of lows is, which requires some size to the system by necessity.
Example 100dB at listening spot 2m away from speakers means the system needs to be able to reproduce 106dB one meter for whole bandwidth, preferably 20Hz-20kHz. Now make sure the speaker system sensitivity is high enough this is possible. For example the 15dB headroom for dynamics is difference between 1W and 40W of amplifier power, so if you have a hifi driver that can handle only 40W of amplifier power the datasheet frequency response graph directly tells you if the driver works in your application: in this case, when ever the frequency response is above 90db/1W/1m in this case, it'll do, because output must be about 90db with 1W at 1m to get into 105db with peaks at 1m with 40W, to have ~100db peaks at listening position. Or how ever one wants to reason with this.
Typical hifi woofers are ~80-90dB sensitive with ~40Watt power capacity, and it is quite easy to see such a driver won't work for this kind of a system requirements, unless you use multiple of, or perhaps for a very small bandwidth. On the other hand, if a driver can handle several hundred watts and datasheet frequency response is +90dB for the bandwidth you have it planned for, then it will.
If AV has 50W per channel, and you have box store speakers with mid 80 sensitivity max, no wonder it sounds mediocre but perhaps it's not amplifier fault. Plug in high sensitivity speakers, and the average amplifier likely sounds just fine. Anyway, amplifiers aside, use what you fancy. Back to speakers.
If you look at frequency responses it of course drops at some low frequency for any driver. To reach 105db at 30Hz for example, is no easy feat but it's not too hard to estimate requirements there as well. Assume simplified situation, closed box system in freespace, and see volume displacement chart here: https://www.diyaudio.com/community/threads/volume-displacement-for-spl-chart.5668/post-55869 which says 105db @ 30Hz requires about 500cm3 of volume displacement, which is roughly 12" woofer doing 1cm p-p excursion. But for bass, you'd likely want more, like 10dB more, or reach to 20Hz, or what ever. 110dB at 20Hz already requires four of 12" woofers doing 1cm p-p excursion. Anyway, it's quite easy to reason few 6" woofers ain't gonna cut it unless they can do inch of excursion. In general, the more you oversize the more sloppier you can be with this kind of calculations and driver selection, but if you must make it very small and simple system, then you must use absolute top notch drivers to reach the desired output. Perhaps less is just fine, 85dB(A) is already quite loud.
Simple calculator here to help: http://www.hometheaterengineering.com/splcalculator.html
Have fun!
Very fundamental stuff for any speaker project. First thing should be to calculate how much SPL capability one needs for given application. Failing to do this makes underwhelming system.
For example for home theatre, perhaps assume 85dB sound level at listening spot + 15dB for dynamics, or if there is a standard you want to follow, take numbers from that one. Now, just calculate what this means in your place with listening distance. It could be complicated if everything is accounted like small room acoustics, but it shouldn't as oversizing is always fine and avoiding undersizing is why you do the calculation in first place. What I mean by undersizing is that it's not problem to reproduce 100dB of treble, but 100dB of lows is, which requires some size to the system by necessity.
Example 100dB at listening spot 2m away from speakers means the system needs to be able to reproduce 106dB one meter for whole bandwidth, preferably 20Hz-20kHz. Now make sure the speaker system sensitivity is high enough this is possible. For example the 15dB headroom for dynamics is difference between 1W and 40W of amplifier power, so if you have a hifi driver that can handle only 40W of amplifier power the datasheet frequency response graph directly tells you if the driver works in your application: in this case, when ever the frequency response is above 90db/1W/1m in this case, it'll do, because output must be about 90db with 1W at 1m to get into 105db with peaks at 1m with 40W, to have ~100db peaks at listening position. Or how ever one wants to reason with this.
Typical hifi woofers are ~80-90dB sensitive with ~40Watt power capacity, and it is quite easy to see such a driver won't work for this kind of a system requirements, unless you use multiple of, or perhaps for a very small bandwidth. On the other hand, if a driver can handle several hundred watts and datasheet frequency response is +90dB for the bandwidth you have it planned for, then it will.
If AV has 50W per channel, and you have box store speakers with mid 80 sensitivity max, no wonder it sounds mediocre but perhaps it's not amplifier fault. Plug in high sensitivity speakers, and the average amplifier likely sounds just fine. Anyway, amplifiers aside, use what you fancy. Back to speakers.
If you look at frequency responses it of course drops at some low frequency for any driver. To reach 105db at 30Hz for example, is no easy feat but it's not too hard to estimate requirements there as well. Assume simplified situation, closed box system in freespace, and see volume displacement chart here: https://www.diyaudio.com/community/threads/volume-displacement-for-spl-chart.5668/post-55869 which says 105db @ 30Hz requires about 500cm3 of volume displacement, which is roughly 12" woofer doing 1cm p-p excursion. But for bass, you'd likely want more, like 10dB more, or reach to 20Hz, or what ever. 110dB at 20Hz already requires four of 12" woofers doing 1cm p-p excursion. Anyway, it's quite easy to reason few 6" woofers ain't gonna cut it unless they can do inch of excursion. In general, the more you oversize the more sloppier you can be with this kind of calculations and driver selection, but if you must make it very small and simple system, then you must use absolute top notch drivers to reach the desired output. Perhaps less is just fine, 85dB(A) is already quite loud.
Simple calculator here to help: http://www.hometheaterengineering.com/splcalculator.html
Have fun!
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edit time over, but I have to add that PA drivers are just fine, and perhaps the ticket if you desire dynamics in general. There really isn't much difference between "hifi" and "PA" technology, physics are same for both, it's just that the PA stuff is optimized for louder output, while hifi stuff has a lot of emotion related marketing and that kind of stuff attached. But, a rational speaker builder doesn't care any of it, other than performance in particular application, right, so it doesn't matter what a driver is marketed for, as long as it meets requirements it's the right one to choose.
That said, first "PA" speakers at home, even though they weren't optimally tuned, the capability just makes smile on the face no small speaker can do, no matter how good it sounds otherwise. It really is quite nice when volume knob can be at any position, and it sounds better and better until hearing system says it's too loud. Distortion free full bandwidth clean comfortably loud sound really is great fun
ps. even a mobile phone can be painfully loud, but the pain is due to small bandwidth and bad distortion, not from sheer SPL
That said, first "PA" speakers at home, even though they weren't optimally tuned, the capability just makes smile on the face no small speaker can do, no matter how good it sounds otherwise. It really is quite nice when volume knob can be at any position, and it sounds better and better until hearing system says it's too loud. Distortion free full bandwidth clean comfortably loud sound really is great fun
ps. even a mobile phone can be painfully loud, but the pain is due to small bandwidth and bad distortion, not from sheer SPL
Just the last paragraph there- I mix LFE into my L/R bass sections for this very reason. I can parallel the HT and "clean" 2ch routing to allow use of surround and width processing, with reduced level and minimal center fill. 4 way active mains make this feasible w 4x12 sealed, 12" horn mid/midbass, and a bms 4595he coax on the waveguides.
But there's no need to feel discouraged in case you use an AVR for amplification.
For instance, there used to be a high-efficiency cinema speaker from JBL (4722/N I think) that was 104dB / 2.83V / 1m when fitted into a full baffle wall (2*pi space). If one were to do the math as mentioned above by tmuikku, it is worth noting that for a small room, this kind of speaker could indeed by powered by an AVR.
Similarly, many people at avsforum have successfully managed to run other cinema models using AVRs at reference levels without problems. However, such speakers are usually large, heavy and so expensive (e.g. >500$ a piece) that buying a few extra amps for these would be a harmless thing to do.
For instance, there used to be a high-efficiency cinema speaker from JBL (4722/N I think) that was 104dB / 2.83V / 1m when fitted into a full baffle wall (2*pi space). If one were to do the math as mentioned above by tmuikku, it is worth noting that for a small room, this kind of speaker could indeed by powered by an AVR.
Similarly, many people at avsforum have successfully managed to run other cinema models using AVRs at reference levels without problems. However, such speakers are usually large, heavy and so expensive (e.g. >500$ a piece) that buying a few extra amps for these would be a harmless thing to do.
A single 10-20db room mode peak at listening spot can make the bass and whole system balance poo. I think good bass management is necessary, whether it is meticulous positioning of things, multisub, EQ or combination of many things, but a mandatory nevertheless This interrelates to system SPL capability, room dominates bass response, gives some boost but also nasty dips and peaks, and really is quite complicated soup. Untreated mode peaks can give false notion of bass, when in reality it's just one or two room modes, the one note bass.
newvirus2008, cool set! While this big is not necessary at home it well illustrates it takes quite a big system to really get loud sound. Small bookshelf speakers, well, perhaps they are fine for bookshelf, it's just important to realize serious application really needs serious system, and it's not too hard to figure out what an application requires. At least, the ballpark figures are easy to estimate.
This interrelates to system SPL capability, room dominates bass response, gives some boost but also nasty dips and peaks, and really is quite complicated soup. Untreated mode peaks can give false notion of bass, when in reality it's just one or two room modes, the one note bass.newvirus2008, cool set! While this big is not necessary at home it well illustrates it takes quite a big system to really get loud sound. Small bookshelf speakers, well, perhaps they are fine for bookshelf, it's just important to realize serious application really needs serious system, and it's not too hard to figure out what an application requires. At least, the ballpark figures are easy to estimate.
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