Lowest frequencies...........infrabass.
Discussion
Crackie said:
David A said:
Not much to add other than I have one of these fairly rare hobbies SVS PB12 ultra/2
http://www.hometheatersound.com/equipment/svs_pb12...
With these dimensions it's a wee bit excessive
Dimensions: 26"H x 19"W x 29"D
Weight: 190 pounds
Must get a much much bigger house.
http://www.hometheatersound.com/equipment/svs_pb12...
With these dimensions it's a wee bit excessive
Dimensions: 26"H x 19"W x 29"D
Weight: 190 pounds
Must get a much much bigger house.
David, that big SVS has impressive performance; I did consider their big 13-Ultra cylinder a while ago but carried away with building my own in the end.
The ported sub above is a wee bit excessive too
Dimensions: 48"H x 24"W x 16"D
Weight: 102 Kg / 224 pounds on scales at work.
Bigger house already sorted.
current one went on the market yesterday. 
telecat said:
The Japanese Hifi Nuts have Horns built into their houses. Most just Like Horn Speakers.
The zero compromise 'architectural' types tend to frequent this forum. http://www.goodsoundclub.com/Forums/ShowPost.aspx?...Edited by Crackie on Friday 24th April 10:20
Crackie said:
Putting aside cinema systems for now, I'm interested to hear PHers thoughts on what low frequency limit you think is needed for convincing 'full range' playback of most music.
Orchestral music with contrabass Bassoons, Clarinets, Harps, Pianos has low frequencies down to 30Hz or so. Big church organs extend into the mid teens but....... how low do you think systems need to go for more contemporary music ?
Is there any benefit in reproducing bass in the 10Hz to 25Hz region ??
Over to you...
When I record classical music it will have zero in that range, because I roll it off.Orchestral music with contrabass Bassoons, Clarinets, Harps, Pianos has low frequencies down to 30Hz or so. Big church organs extend into the mid teens but....... how low do you think systems need to go for more contemporary music ?
Is there any benefit in reproducing bass in the 10Hz to 25Hz region ??
Over to you...
A number of reasons:
1) Most mics don't pick up in that range.
2) Most mic pre-amps actually will roll off that range anyway. Good mic pre-amps like Focusrite etc have the additional option of setting a high pass filter. The thinking is that this increases the fidelity of the captured audio without the worthless very low bass.
3) There is very little energy at those wavelengths because of the above, and
4) The realities of recording an orchestra on location or a studio is that a good proportion of the energy at those wavelengths will be stuff you want to exclude - rumblings from floors, traffic, extraneous sounds etc.
5) On top of all the above, when it comes to mastering, those frequencies are again rolled off. Two reasons, firstly to stop 'mega bass' type hifi stuff from just amplifying it and distorting it, and secondly once it goes to radio and they compress it for broadcast, your song would sound quieter in relation to the rest as the compressor would be affected by the low bass even though its inaudible.
On the last point, I remember a lecture from someone - I think it might have been Pete Waterman back in the day - saying that they would roll off everything low down, and even the bass would be more mid-range sounding so that their song would be less limited, and sound louder on the radio.
Have a listen to SAW stuff from the 80's and it's pretty noticeable!
So, in short, I wouldn't bother.
JustinP1 said:
When I record classical music it will have zero in that range, because I roll it off.
A number of reasons:
1) Most mics don't pick up in that range.
2) Most mic pre-amps actually will roll off that range anyway. Good mic pre-amps like Focusrite etc have the additional option of setting a high pass filter. The thinking is that this increases the fidelity of the captured audio without the worthless very low bass.
3) There is very little energy at those wavelengths because of the above, and
4) The realities of recording an orchestra on location or a studio is that a good proportion of the energy at those wavelengths will be stuff you want to exclude - rumblings from floors, traffic, extraneous sounds etc.
5) On top of all the above, when it comes to mastering, those frequencies are again rolled off. Two reasons, firstly to stop 'mega bass' type hifi stuff from just amplifying it and distorting it, and secondly once it goes to radio and they compress it for broadcast, your song would sound quieter in relation to the rest as the compressor would be affected by the low bass even though its inaudible.
On the last point, I remember a lecture from someone - I think it might have been Pete Waterman back in the day - saying that they would roll off everything low down, and even the bass would be more mid-range sounding so that their song would be less limited, and sound louder on the radio.
Have a listen to SAW stuff from the 80's and it's pretty noticeable!
So, in short, I wouldn't bother.
Hi Justin, thanks for the comprehensive reply; I appreciate your knowledge and experience in the recording field but your comments focus on microphone recording of real instruments and voices; the low frequency content of electronically generated music often very different. I started the subwoofer project(s) to be able to cover full range electronic music.A number of reasons:
1) Most mics don't pick up in that range.
2) Most mic pre-amps actually will roll off that range anyway. Good mic pre-amps like Focusrite etc have the additional option of setting a high pass filter. The thinking is that this increases the fidelity of the captured audio without the worthless very low bass.
3) There is very little energy at those wavelengths because of the above, and
4) The realities of recording an orchestra on location or a studio is that a good proportion of the energy at those wavelengths will be stuff you want to exclude - rumblings from floors, traffic, extraneous sounds etc.
5) On top of all the above, when it comes to mastering, those frequencies are again rolled off. Two reasons, firstly to stop 'mega bass' type hifi stuff from just amplifying it and distorting it, and secondly once it goes to radio and they compress it for broadcast, your song would sound quieter in relation to the rest as the compressor would be affected by the low bass even though its inaudible.
On the last point, I remember a lecture from someone - I think it might have been Pete Waterman back in the day - saying that they would roll off everything low down, and even the bass would be more mid-range sounding so that their song would be less limited, and sound louder on the radio.
Have a listen to SAW stuff from the 80's and it's pretty noticeable!
So, in short, I wouldn't bother.
Regarding whether to bother or not; I've already made the ported sub above. I'm fortunate to have access to a CNC at work so making a big sub, which can reproduce 15Hz cleanly and at good level, hasn't cost me too much. There's another sub design in the pipeline ( cab designed but not started yet ) and I wanted to hear people's thoughts/experiences about infrasound before starting to make it. Mrs Crackie isn't too impressed with the idea of another big enclosure in the house.........not when I explained it was 2.75m tall and 1000 liters.
Edited by Crackie on Sunday 26th April 08:56
I still think synthetic instruments will be reproduced the same way for some of the reasons I mentioned.
A lot of systems will be worse if they reproduced 10-25Hz. A real world example is when I saw Interstellar I could hear distortion in the score, but only when there was rumbling - this was at a brand new IMAX screen cinema.
What was going on was that the very low frequencies on the speaker drivers were actually reducing the 'data' on the low end.
I watched the same film on a friends setup which is 7.1 of B&W 800 series, identical to the Skywalker Sound and Abbey Rd. There was none of the distortion I heard previously.
My gut feeling is that for everything you add in the 10-20Hz range, you'll lose fidelity on whatever is also also on that driver, so it'll be a double edged sword.
To do it properly, IMHO you'd need a sub for say 30Hz to 80Hz or whatever top end meets your speakers, and a specific sub for lower than 30Hz.
Then you've got the best of both worlds. As long as you can get them to fire in phase...
A lot of systems will be worse if they reproduced 10-25Hz. A real world example is when I saw Interstellar I could hear distortion in the score, but only when there was rumbling - this was at a brand new IMAX screen cinema.
What was going on was that the very low frequencies on the speaker drivers were actually reducing the 'data' on the low end.
I watched the same film on a friends setup which is 7.1 of B&W 800 series, identical to the Skywalker Sound and Abbey Rd. There was none of the distortion I heard previously.
My gut feeling is that for everything you add in the 10-20Hz range, you'll lose fidelity on whatever is also also on that driver, so it'll be a double edged sword.
To do it properly, IMHO you'd need a sub for say 30Hz to 80Hz or whatever top end meets your speakers, and a specific sub for lower than 30Hz.
Then you've got the best of both worlds. As long as you can get them to fire in phase...
JustinP1 said:
To do it properly, IMHO you'd need a sub for say 30Hz to 80Hz or whatever top end meets your speakers, and a specific sub for lower than 30Hz.
I have exactly that in mind........the main speakers in my current setup use four Celestion 12" paper/Kevlar woofers in 2.4m long quarter wave enclosures which cover 25Hz to 85Hz. The 240L Peerless reflex sub shown earlier in the thread, and the pictures below, is to cover below that; a digital active crossover sorts bandwidth, phase integration and delays etc. Regarding the B&W cinema system performing better than the IMAX setup. B&W's 800 series are very good; arguably the bigger PMCs, ATCs, Wilson Audios, Krells, Martens, Gryphons, Nolas, Magicos, Velodyne's etc etc are similarly well engineered and also capable of reference quality bass.
I'm delighted with how well build quality, if not my first attempts at veneering
has turned out. In addition to the interlocking bracing, a lot of work went into the inspecting the impedance trace when fitting the constrained layer mass damping plates and standing wave damping used. Port area is very high at 282 square cm; internal and external openings are chamfered to keep turbulence to a minimum. The impedance measurement and the high power sinewave tests are very clean as a result. Interlocking bracing
40Kg worth of constrained layer steel damping plates glued and screwed to the cabinet walls.
Standing wave damping is a combination of carpet underlay and denim batting.
The benefit of going the extra mile with the bracing and damping is the extremely low total harmonic distortion (THD) result. The 122.5dB measurement in the graph below was taken at 12.5cm distance; this is equivalent to 105dB at 1m.
Edited by Crackie on Saturday 2nd May 23:40
I was considering having maybe 4 x 12" LAB 12 speakers at the front to cover down to about 30Hz and moving my existing 15" subs to the rear to cover 40Hz down (to allow for some overlap and to cover a null at 35Hz). However, I mentioned this over on AVForums and you'd have thought I was contemplating brain surgery with a blunt spoon. Apparently it's all far too complicated to mix drivers/frequency ranges. 
I've played around with the DSP/eq in my subwoofer amp and done various measurements using REW. You can really see how maintaining flat down to 10Hz, verses allowing more of a roll off makes a big difference to the level you can run at. Going below 20Hz (especially sealed) really takes a lot more power, though certain films do seem to benefit in having the below 20Hz content produced. I happen to have a fair amount of room gain, so this helps compensate for the natural roll off when using a sealed sub(s), so I'm quite flexible as to which option I choose.
Having said that I don't feel that I suffer the issue mentioned above regarding the IMAX screening of Interstellar, but then I'm filling a much smaller space with probably more capable subwoofers (relative to the room size). IMHO commercial cinemas rarely have good sound as there always seems to be at least one rattly speaker/sub somewhere whenever I go, which is why I prefer to wait for new films to come out on BluRay and watch them at home...
Apparently it's all far too complicated to mix drivers/frequency ranges. I've played around with the DSP/eq in my subwoofer amp and done various measurements using REW. You can really see how maintaining flat down to 10Hz, verses allowing more of a roll off makes a big difference to the level you can run at. Going below 20Hz (especially sealed) really takes a lot more power, though certain films do seem to benefit in having the below 20Hz content produced. I happen to have a fair amount of room gain, so this helps compensate for the natural roll off when using a sealed sub(s), so I'm quite flexible as to which option I choose.
Having said that I don't feel that I suffer the issue mentioned above regarding the IMAX screening of Interstellar, but then I'm filling a much smaller space with probably more capable subwoofers (relative to the room size). IMHO commercial cinemas rarely have good sound as there always seems to be at least one rattly speaker/sub somewhere whenever I go, which is why I prefer to wait for new films to come out on BluRay and watch them at home...
I hadn't got that far TBH, some one mentioned them as a possibility as a reasonably priced fairly shallow 12" driver. Another option was to use FiQ 12" but they are pretty deep and barely any cheaper than more FiQ 15" would be, hence me thinking about just going for two more FiQ 15. At least they would all match making set up easier, but I'm not sure I want to lose nearly 1 foot at each end of the room to have them hidden in the 'wall'.
Here's a link, http://www.eminence.com/pdf/LAB_12_cab.pdf.
Eminence themselves stress you need to take care with filtering.
You might be interested in the IB HT ( infinite baffle home theater series ) from Acoustic Elegance; developed specifically for home theater applications like yours. Sensible money too but you'll need to import them.
http://aespeakers.com/aes_store/catalog/product_in...
http://ibsubwoofer.blogspot.co.uk/2007/11/new-ae-i...
Eminence themselves stress you need to take care with filtering.
You might be interested in the IB HT ( infinite baffle home theater series ) from Acoustic Elegance; developed specifically for home theater applications like yours. Sensible money too but you'll need to import them.
http://aespeakers.com/aes_store/catalog/product_in...
http://ibsubwoofer.blogspot.co.uk/2007/11/new-ae-i...
Edited by Crackie on Saturday 25th April 07:38
JustinP1 said:
I watched the same film on a friends setup which is 7.1 of B&W 800 series, identical to the Skywalker Sound and Abbey Rd. There was none of the distortion I heard previously.
I would have assumed that this was down to calibration? Is the B&W really that good? I've heard and installed a few of their 800 setups and found them to be very good but I wouldn't of expected them to perform particularly well in relation to the very low bass mentioned here.I really like the very high end ATC stuff. I have only heard it once in a listening room but to my ears it was absolute perfection. If I ever get in to serious hifi at home they will be getting my money.
That subwoofer build below is mental! Your wife must be very accommodating!
Crackie said:
Here's a link, http://www.eminence.com/pdf/LAB_12_cab.pdf.
Eminence themselves stress you need to take care with filtering.
You might be interested in the IB HT ( infinite baffle home theater series ) from Acoustic Elegance; developed specifically for home theater applications like yours. Sensible money too but you'll need to import them.
http://aespeakers.com/aes_store/catalog/product_in...
http://ibsubwoofer.blogspot.co.uk/2007/11/new-ae-i...
Yes I came across the AE series, I was looking at the 12" TD12S model, but as you say it's the hassle of importing them, hence taking the easier option of buying from somewhere like Blade Ice where I got my Fi Q 15" from last year.Eminence themselves stress you need to take care with filtering.
You might be interested in the IB HT ( infinite baffle home theater series ) from Acoustic Elegance; developed specifically for home theater applications like yours. Sensible money too but you'll need to import them.
http://aespeakers.com/aes_store/catalog/product_in...
http://ibsubwoofer.blogspot.co.uk/2007/11/new-ae-i...
Edited by Crackie on Saturday 25th April 07:38
http://www.aespeakers.com/drivers.php?driver_id=11
I'd need to load those parameters into WinISD to see if they would work in the volume I have available, but I'm not that confident about doing it, so I might reverse engineer one or two that are already in WinISD to make sure I've got it right. Just a matter of getting round to it really.
I missed you post above with the cabinet. Looks a very sturdy build, what device(s) are you going to use to set up the two subwoofer systems? I have the DSP in my iNuke to sort individual delays/filters/pre eq, plus probably the DDRC88A to eq all the subs as one item.
OldSkoolRS said:
I missed you post above with the cabinet. Looks a very sturdy build, what device(s) are you going to use to set up the two subwoofer systems? I have the DSP in my iNuke to sort individual delays/filters/pre eq, plus probably the DDRC88A to eq all the subs as one item.
There is a MiniDSP 10 channel digital active crossover / pre-amp at the heart of my system. I use 8 channels to drive the main four way active system and the unused pair of outputs will control and optimise the subs.
Measurements are done by Clio, ARTA and Holmimpulse software via a Tascam audio interface. The active crossover sorts out the pass bands for the various drivers, the time alignments, phase correction, parametric driver EQ. Once that's all sorted the signals are fed via the MiniDSPs volume control to various power amps.
OldSkoolRS said:
That's great information Crackie. I've heard of Holmimpulse before, though I'm only using an UMIK-1 myself which is a USB mic, so I'm not able to do time based loop measurements. I might have to look into another mic/soundcard solution myself when I get started on my sub upgrade.
ARTA http://www.artalabs.hr/ and Holmimpulse http:/ /www.holmacoustics.com/holmimpulse.php are both incredible pieces of freeware. Holm is arguably the best for time alignment but overall ARTA is as capable a development tool as top commercial systems like CLIO or MLSSA. Check out the registered users on ARTA's website. Hi-Fi Choice have been using it for a while too. The program provides impulse response measurement, for real-time spectrum analysis and for real-time frequency response measurements. The ARTA program is also a powerful analyzer of gated impulse response, smoothed frequency response (in 1/n-octave bands), step response, impulse response envelope (ETC curve), cumulative spectral decay curve, energy decay in reverberant environments, room acoustical parameters and speech intelligibility measures - STI and RASTI.
The package includes modules to allow impedance, TSP, Harmonic distortion measurements as well as the usual sine and FFT suite.
Edited by Crackie on Sunday 26th April 20:29
NorthDave said:
JustinP1 said:
I watched the same film on a friends setup which is 7.1 of B&W 800 series, identical to the Skywalker Sound and Abbey Rd. There was none of the distortion I heard previously.
I would have assumed that this was down to calibration? Is the B&W really that good? I've heard and installed a few of their 800 setups and found them to be very good but I wouldn't of expected them to perform particularly well in relation to the very low bass mentioned here.My friend has 800's and the huge HTM1 centre speaker (that they don't make any more), as well as two subs at the front.
To my ears it was reproducing everything encoded on the source.
I
JustinP1 said:
I've had 804s 803s and 802s at the moment and thats great for a reasonable sized room.
My friend has 800's and the huge HTM1 centre speaker (that they don't make any more), as well as two subs at the front.
To my ears it was reproducing everything encoded on the source.
How do you know what was encoded at the source?My friend has 800's and the huge HTM1 centre speaker (that they don't make any more), as well as two subs at the front.
To my ears it was reproducing everything encoded on the source.
fulgurex said:
I
A reasonable guess, from an understanding of what is likely to have been in the source, and professional experience in audio recording, mixing and mastering.JustinP1 said:
I've had 804s 803s and 802s at the moment and thats great for a reasonable sized room.
My friend has 800's and the huge HTM1 centre speaker (that they don't make any more), as well as two subs at the front.
To my ears it was reproducing everything encoded on the source.
How do you know what was encoded at the source?My friend has 800's and the huge HTM1 centre speaker (that they don't make any more), as well as two subs at the front.
To my ears it was reproducing everything encoded on the source.
Also a comparison with my local cinema, which I could hear straight away was not reproducing what was encoded adequately.
Crackie said:
OldSkoolRS said:
I'm going to another dealer for an open day in a few weeks time to hear the '88 in action, so will see how I get on.
I'd be interested to hear what you think ??.I went to Kalibrate over in Caterham a few weeks ago for an open day. One of many things we were shown was the miniDSP DDRC-88A and a run through of how to calibrate it. In short I came home with one, a returned unit so I got £100 off on the understanding that if it had any issues then I would return it. (In fact I didn't even pay for it until I'd got it working properly at home, which was very trusting of Ricky, but I've bought a lot of gear from him over the years).
It really is a remarkable piece of kit. I reset my iNuke sub amp to neutral, apart from a delay to the nearest of two subs (it is about 1.5 metres closer and behind the MLP). I ran the 9 point calibration and saved this in slot 1. Straight away I could hear that the edgyness that XT32 gave me had gone, leaving the high end much smoother and with fantastic imaging in stereo (and surround). It does a much better job of integrating the subs (since the test tones use the sub and whichever speaker is being measured unlike XT32).
My centre speaker is an on wall MK MP150, but I have slightly recessed it into the wall to allow clearance behind my TV (which raises up on an electric lift when I want to watch a film on the projector). This has made the centre sound slightly boomy, so I had previously raised the crossover to 150Hz which helped, but I then felt that the surrounds lost 'weight' since the bass is being directed away from them. With Dirac engaged the centre now sounds like a huge floorstander (as do all the speakers for that matter) and no trace of the 'boom' even with the crossover lowered to 100Hz (to allow for my surround backs as it is a global setting). The pink noise test tone from my AV8 (via the'88) sound identical for each speaker, which shows how well it has corrected them and blended the sub. I do plan to properly locate the centre during next year's room revamp, but this will do very well for now.
The bass is so much better too, richer with music, but tighter/cleaner sounding too: With XT32 and also with manually eqing my subs I always end up bumping up the sub level to try to get the bass sound I like. There is no need with Dirac (though it does set up an 'auto target' eq curve it only raises 20Hz by 2dB more than 100Hz, so nothing like the 6-8dB level boost I usually end up adding).
The targets are useful too since I tend to use the 'THX' mode on my current AV processor to matrix the surround backs for 5.1 to 7.1 sound. However this mode includes a treble roll off which combined with the Dirac 'auto target' left it sounding a little too dull. No problem as using the Dirac software, I just clicked on the target button at 20Khz and dragged it back up to 0dB to give a flat response from 1 to 20Khz, saved in another of the DDRC-88A's 4 memory slots. The THX mode in my AV8 then rolls this offslightly leaving me the ideal overall response.
Since the initial 9 point calibration was done with my 10' screen lowered and the curtains closed I can now do another calibration with the screen away and curtains open, AKA a 'day time' setting (the way I'd typically listen to CDs). This can be saved in any of the other memory slots. The target for these settings can also be tweaked if the 'auto target' isn't quite what I want, though so far for straight stereo I'm very happy with it. It's easy enough to reload settings and calibrations back into the '88 using the Dirac software so you can make more calibrations and target curves beyond the 4 memories, yet you can load them back in at any time (just need to save them with logical sounding names to help identify them).
It is very flexible, though ironically I'm likely to just use a couple of settings; screen down with flat top end for post THX processing, screen down auto target for any other 7.1 content non THX post processing and screen away (aka 'daytime mode') auto target. Still leaves a spare memory if I think of any other scenarios I could use it for.
Crackie said:
OldSkoolRS said:
I've been thinking that next year I might build a baffle wall and put 4 x 12" subs in the front of my room and move both 15" to the rear in a similar baffle wall, so all speakers/subs will be hidden. That should give me a pretty decent response according to REW room sim (and plenty of headroom) leaving the eq with less work to do. Might take a bit of setting up, but I reckon it would be worth it.
Sounds like an plan........... good luck. Edited by OldSkoolRS on Wednesday 20th May 16:37
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