BradC Posted March 7, 2014 Posted March 7, 2014 I presently have a sub at the front and one at the rear to achieve a reasonably smooth bass response. After listening to vandersteen 7 speakers with their powered subwoofers, much more bass punch was apparent. I found out that vandersteen crosses the subs at 100Hz with a first order crossover. In my experiments I found that at about 100Hz crossover freq, I could begin to locate the position of the sub, and that was with a steeper crossover. Hence to replicate the effect of the vandersteen subs, I would have to position both subs near the mains. A third or fourth sub, albeit of minimal size and power, would then be required to achieve a smooth room response. Has anyone experimented with stereo subs? Any suggestions for subs that only need to cover 40-80Hz? I will eventually do the experiment, but was interested in thoughts on the matter
henry218 Posted March 7, 2014 Posted March 7, 2014 (edited) you must like BASSS very much ( sorry i thought u want to add subwoofers to the 7 ) the V 7 highpassed the MT, so its alot more going on with the speakers than just add subs. What makes you inclined to use 1st order for the subs? and what are the speakers you're trying to integrated it with? cheers henry Edited March 7, 2014 by henry218
BradC Posted March 7, 2014 Author Posted March 7, 2014 you must like BASSS very much ( sorry i thought u want to add subwoofers to the 7 ) the V 7 highpassed the MT, so its alot more going on with the speakers than just add subs. High passed the MT?? My mains are vaf i66 From what I can ascertain, the bass punch occurs somewhere from 50-150Hz. Phrased another way, are the benefits of using subs in a stereo config, and lowpassing them at a higher freq, greater than the benefit of a smoother room response for <80Hz? 1
hochopeper Posted March 7, 2014 Posted March 7, 2014 Were the two listening experiences that you describe in different rooms? It is rather unlikely that the differences were due to 'stereo' subwoofers.
BradC Posted March 7, 2014 Author Posted March 7, 2014 yes 2 totally different systems and rooms It's not so much whether the subs are stereo, but the crossover point. At 80Hz, the subs don't do a lot with music. They do add 'weight', but not much more
henry218 Posted March 7, 2014 Posted March 7, 2014 (edited) High passed the MT?? My mains are vaf i66 the model 7 is a 4way, where signals below 100hz electronically high passed to the midbass, midrange and tweeter.it means the responses below 100hz from the midbass is being attenuated, so the model 7 is whole speakers with subs, its not like what you are trying to do with the Vaf i66, where the subs is bass helper. Edited March 7, 2014 by henry218
Stump Posted March 7, 2014 Posted March 7, 2014 Blending in subs with a Stereo Amp from what I have read is not so successful.I am running 3x Vaf platform subs with a Arcam AVR 600 with great success.The Subs are equalized with the Arcam for multichannel music ,CD and Vinyl.When first running 2x Subs behind front speakers there was only a couple of null spots in the room.After adding the x1 sub behind the listen chair it filled in those spots.With the room treatments there is not SUB BOOM and as they blend in with the mains you can not hear where the subs placements are! Stump
BradC Posted March 7, 2014 Author Posted March 7, 2014 the model 7 is a 4way, where signals below 100hz electronically high passed to the midbass, midrange and tweeter. it means the responses below 100hz from the midbass is being attenuated, so the model 7 is whole speakers with subs, its not like what you are trying to do with the Vaf i66, where the subs is bass helper. I am using a HTPC to drive all the speakers. I have complete freedom to high pass and low pass with any crossover type to any speaker. At the moment I actually have 14 different sub FIR EQ filters. 2 subs supporting 7 channels. The bass is smooth and I cannot locate the front and rear sub positions by ear. But has anyone compared stereo subs to subs placement to optimise smoothness?
BradC Posted March 7, 2014 Author Posted March 7, 2014 Blending in subs with a Stereo Amp from what I have read is not so successful.I am running 3x Vaf platform subs with a Arcam AVR 600 with great success.The Subs are equalized with the Arcam for multichannel music ,CD and Vinyl.When first running 2x Subs behind front speakers there was only a couple of null spots in the room.After adding the x1 sub behind the listen chair it filled in those spots.With the room treatments there is not SUB BOOM and as they blend in with the mains you can not hear where the subs placements are! Stump If you turned off one of your subs at the front, would you notice? Also, what crossover freq do you use for the subs at the front? If ~80Hz, have you experimented with higher xover freqs?
ArthurDent Posted March 7, 2014 Posted March 7, 2014 Has anyone experimented with stereo subs? I run stereo subs located on the wall behind the mains and additional subs at the rear of the room. Not sure about the 1st order crossovers at 100hz though, I'm using 4th order linear phase (FIR DSP) LR at 80hz.
davewantsmoore Posted March 7, 2014 Posted March 7, 2014 By using 1st order you avoid some compromises and create many others. Here's what happens to a driver high pass filtered at 1khz depending on it's steepness. Anything less than 2nd order, means you must have a 'heroic' driver. RV builds his own drivers which can handle this, but like I said, it's a compromise he's chosen. Obviously if we are talking about a HPF at 100hz .... Then we essential need a "subwoofer" driver, as the excursion below 100hz INCREASES (even though the output decreases)
henry218 Posted March 7, 2014 Posted March 7, 2014 By using 1st order you avoid some compromises and create many others. Here's what happens to a driver high pass filtered at 1khz depending on it's steepness. Anything less than 2nd order, means you must have a 'heroic' driver. RV builds his own drivers which can handle this, but like I said, it's a compromise he's chosen. Obviously if we are talking about a HPF at 100hz .... Then we essential need a "subwoofer" driver, as the excursion below 100hz INCREASES (even though the output decreases) u think his mains will have problem with HPF @100hz?
Grumpy Posted March 7, 2014 Posted March 7, 2014 (edited) I really don't understand all the techy stuff, but a couple of amazing GTG listening experiences for me were when subs were included in the actual speakers - I speak of Mondies ADAMs and Darthlakers Vanders. Truly great sounds on the day. I have tried hooking my 2 subs up to add that little extra to my VAF DCX's, but I wasn't that happy with the sound although I didn't spend much time experimenting with them. Having said that I still think the best 'solid' bass I've heard was from a pair of VAF 1.93's at peterpans a couple of years ago. Edited March 7, 2014 by Grumpy
betty boop Posted March 7, 2014 Posted March 7, 2014 Brad I have run "stereo subs" however soon found absolutely no benefit. one of my subs is plenty to energise the room and in response / smoothness etc does just fine without need of the other or 2ch duties (ie I use to extend my mains for a full range response). for ht duties ofcourse both subs are utilised. but again not in a stereo config. I presently have a sub at the front and one at the rear to achieve a reasonably smooth bass response. After listening to vandersteen 7 speakers with their powered subwoofers, much more bass punch was apparent. I found out that vandersteen crosses the subs at 100Hz with a first order crossover. In my experiments I found that at about 100Hz crossover freq, I could begin to locate the position of the sub, and that was with a steeper crossover. Hence to replicate the effect of the vandersteen subs, I would have to position both subs near the mains. A third or fourth sub, albeit of minimal size and power, would then be required to achieve a smooth room response. Has anyone experimented with stereo subs? Any suggestions for subs that only need to cover 40-80Hz? I will eventually do the experiment, but was interested in thoughts on the matter carefull... what you have in front back is actual ideal arrangement. if wanting more in subs left and right centre of side walls is next step. however what your talking in the vandersteens is likely a completely different speaker with subs well integrated and located probably better that you have. there are so many variables here in comparing, from room, speakers (system driving), subs, setup/location, and listening position - you really cant compare like that. the only thing stereo subs will bring is possibly better chance of integration with the mains with co location. but keeping in mind the location of mains might not coincide with ideal placement for sub as well. And yes 100hz is on the higher side and not suprised can start to locate and while will work in collocated arrangements wont work that great if split from the mains. your listening position that havent mentioned is probably extremely important too....
Satanica Posted March 7, 2014 Posted March 7, 2014 Has anyone experimented with stereo subs? I will eventually do the experiment, but was interested in thoughts on the matter I have expermiented and am using stereo subs, here's what I have/did: http://www.stereo.net.au/forums/index.php?/topic/52992-add-two-more-subwoofers-to-my-system-i-already-have-two/#entry879586 There's actually two subs for the left channel and two for the right. After some expermientation, the bookshelf top speaker modules are crossed over to the subs at 180Hz at 72db/octave and the SVS subs (square ones) are running at 180o phase. I'm pretty happy with the results at the moment.
Peter_F Posted March 7, 2014 Posted March 7, 2014 Do stereo subs actually add "punch"? ITI what are we talking about when we say "punch"?
betty boop Posted March 7, 2014 Posted March 7, 2014 Do stereo subs actually add "punch"? ITI what are we talking about when we say "punch"? 1stly if running as subs ie under 80hz, thats not localised in sound, so the whole concept of "stereo" is a non event. running higher than that yes sound is going to be localised and "stereo" as a concept is more real. though I would challenge running subs that high and say thats heading into woofer territory and the woofers in your mains might be better off left to doing those freq. prob something specific to systems, speakers and mains. I dont think there are cookie cutter answers to these things... as far as punch goes, I would say function of your mains/subs/system and positioning. the punch might be a result of either your sub or mains ability to do punch and location of speakers/sub and listening position/room. but punch itself has nothing to do with stereo subs as such I would say
ArthurDent Posted March 7, 2014 Posted March 7, 2014 (edited) Here are some popular distances (front of cabinet to the wall behind) and the corresponding null frequency in the response (a rather large one) caused by the reflection of the wall... 800mm 107hz 900mm 95hz 1000mm 86hz 1100mm 78hz 1200mm 72hz 1300mm 66hz 1400mm 61hz This is why you use stereo subs hard up against the wall behind your main stereo speakers and cross over to them somewhere between 80 and 100hz. Edited March 7, 2014 by KenTripp 1
Peter_F Posted March 7, 2014 Posted March 7, 2014 ......but punch itself has nothing to do with stereo subs as such I would say That's what I was thinking too.
BradC Posted March 7, 2014 Author Posted March 7, 2014 By using 1st order you avoid some compromises and create many others. Here's what happens to a driver high pass filtered at 1khz depending on it's steepness. Anything less than 2nd order, means you must have a 'heroic' driver. RV builds his own drivers which can handle this, but like I said, it's a compromise he's chosen. Obviously if we are talking about a HPF at 100hz .... Then we essential need a "subwoofer" driver, as the excursion below 100hz INCREASES (even though the output decreases) How is the excursion determined? In the case where the woofer isn't HP filtered at all, how is any HPF worse? I am pretty sure the vaf signature series also use first order crossovers for all the drivers
Stump Posted March 7, 2014 Posted March 7, 2014 If you turned off one of your subs at the front, would you notice? Also, what crossover freq do you use for the subs at the front? If ~80Hz, have you experimented with higher xover freqs? With one sub off in front I wouldn't notice sitting in the sweet spot! I use 80Hz and have played around with 40Hz -120Hz. Stump 1
davewantsmoore Posted March 7, 2014 Posted March 7, 2014 But has anyone compared stereo subs to subs placement to optimise smoothness? Sounds over roughly 100hz can be localized. The biggest issue with subwoofers, aside from what Hz and how steep the LPF is ..... is distortion. Harmonic distortion components of 40hz, could easily fall above audibility .... and hence H3 (120Hz) could localise the subwoofer.
davewantsmoore Posted March 7, 2014 Posted March 7, 2014 I am pretty sure the vaf signature series also use first order crossovers for all the drivers If you use a first order HPF, then the excursion of the driver continues to increase as you go down in Hz..... ie, you have 1mm excursion at 1khz .... you will have much MORE excursion at 20hz. If you use a 2nd order HPF, the excursion remains constant .... ie. If you have a HPF at 1khz... and you have 1mm excursion .... then you will also have 1mm excursion from 20hz signals. If you use a steeper filter, the excurison of the driver will decrease below the crossover. Using a 1st order XO, just mean you have to choose a driver which can handle this excursion .... sometimes, easier said than done .... but you have to choose a 'compromise' somewhere. 1st order filters give you other benefits.
davewantsmoore Posted March 7, 2014 Posted March 7, 2014 Do stereo subs actually add "punch"? ITI what are we talking about when we say "punch"? *nods* These discussions are difficult. I think the OP means in the 100-200hz region... where a sub with a not so steep LPF (like a vendersteen setup) would be allowed to run. Unfortunately avoiding low order crossovers, really means active filters (complexity) is required. You can see why people stick with them.
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