avklipsch Posted December 8, 2004 Share Posted December 8, 2004 Hi, I am moving into a new house and am going to have my own space for a home theater. The room is 11x20. I will be going with heresys all the way around. I durrently own 1 cs ultra with the 1000 samson and 2 rf5's. My question is would I be better off with adding the pb12 ultra 2, or selling the the current ultra and jumping to the b12 plus 4. One can never have enough bass!!! Thanks in advance!!! AAron Quote Link to comment Share on other sites More sharing options...
jfmacken Posted December 8, 2004 Share Posted December 8, 2004 Either way, I think you would have more powerful bass than the local movie theater! I would probably go with the B4, those look really scary. Quote Link to comment Share on other sites More sharing options...
Jay481985 Posted December 8, 2004 Share Posted December 8, 2004 11X20? a PB12 Ultra was usually designed for a big room like 20X30 or so... So I'd presume even one PB12 Ultra would be overkill Quote Link to comment Share on other sites More sharing options...
meuge Posted December 8, 2004 Share Posted December 8, 2004 Room size is a severe limiter of bass performance. Down the long axis of the room, you will start to lose coherency at 50Hz, since the wave will no longer fit inside the room. For example, the lowest note on the piano is around 29Hz. To fit that wave inside a room, the axis of the room must be around 35 feet wide. If the room is half that size, the SPL of that note will be severely diminished by cancelation effects of the room resonance. I know it sucks - my room is even smaller. Quote Link to comment Share on other sites More sharing options...
DillonW Posted December 9, 2004 Share Posted December 9, 2004 If you find that one ultra is insufficent, I would go with the Ultra/2 over the B4+. I think the Ultra drivers are notably better than the plus, especially at high volume. I like my PB12 Plus/2, but the Ultra/2 is just so sweet! Quote Link to comment Share on other sites More sharing options...
killerbee_vr6 Posted December 9, 2004 Share Posted December 9, 2004 ---------------- On 12/8/2004 8:10:36 PM meuge wrote: Room size is a severe limiter of bass performance. Down the long axis of the room, you will start to lose coherency at 50Hz, since the wave will no longer fit inside the room. For example, the lowest note on the piano is around 29Hz. To fit that wave inside a room, the axis of the room must be around 35 feet wide. If the room is half that size, the SPL of that note will be severely diminished by cancelation effects of the room resonance. I know it sucks - my room is even smaller. ---------------- Which completely explains excellent low-bass performance in cars and with headphones. Quote Link to comment Share on other sites More sharing options...
formica Posted December 9, 2004 Share Posted December 9, 2004 ---------------- On 12/8/2004 7:47:56 PM av wrote: I will be going with heresys all the way around. I durrently own 1 cs ultra with the 1000 samson and 2 rf5's. My question is would I be better off with adding the pb12 ultra 2, or selling the the current ultra and jumping to the b12 plus 4. One can never have enough bass!!! ---------------- Unless you run the sub quite "hot"... the Heresys will run out of steam before the PB12-U2 will. If/when you eventually upgrade your mains ... you may want more sub again. Sooooo... the call is up to you... Rob Quote Link to comment Share on other sites More sharing options...
pinipig523 Posted December 9, 2004 Share Posted December 9, 2004 This is what I think you should do, then: Sell the CSultra. Buy TWO PB2+. DONE. Hands down the best deal around. Two PB2+ have more internal volume and port surface area than a B4+. For this reason, I would prefer two PB2+. OR TWO PB2ultras if you can afford it. Quote Link to comment Share on other sites More sharing options...
CAS Posted December 9, 2004 Share Posted December 9, 2004 ---------------- On 12/9/2004 4:43:43 AM pinipig523 wrote: This is what I think you should do, then: Sell the CSultra. Buy TWO PB2+. DONE. Hands down the best deal around. Two PB2+ have more internal volume and port surface area than a B4+. For this reason, I would prefer two PB2+. OR TWO PB2ultras if you can afford it. ---------------- HEAR HEAR!!! Quote Link to comment Share on other sites More sharing options...
Seismic_Pulse Posted December 9, 2004 Share Posted December 9, 2004 ---------------- On 12/9/2004 12:21:37 AM killerbee_vr6 wrote: ---------------- On 12/8/2004 8:10:36 PM meuge wrote: Room size is a severe limiter of bass performance. Down the long axis of the room, you will start to lose coherency at 50Hz, since the wave will no longer fit inside the room. For example, the lowest note on the piano is around 29Hz. To fit that wave inside a room, the axis of the room must be around 35 feet wide. If the room is half that size, the SPL of that note will be severely diminished by cancelation effects of the room resonance. I know it sucks - my room is even smaller. ---------------- Which completely explains excellent low-bass performance in cars and with headphones. ---------------- killerbee_vr6 Did you edit your post? I could have sworn your reply to meuge was the exact opposite and for that reason I thought I learned something about the difference between HT and car subs. EDIT: I see that you did not make any revisions to your post so I must have read it incorrectly. Still it seems what you and meuge are saying are two completely different things. meuge & killerbee_vr6 Way back I questioned why car subs have such huge magnets and needed so much power vs. HT subs. I was told that car systems and car subs are much more inefficient. I never really put much thought into this until last night reading meuge's post when I thought it all clicked. From meuge's post and killerbee_vr6's reply I thought I finally understood why this was. Car systems are in a much smaller space and it is much more difficult to produce low frequency's in a space that is not large enough for wave completion. I also thought you have to purchase a sub based upon room dimensions. From what I gather from this post and reply your HT will not live up to its potential unless placed in a room where it can in my words breathe. Could someone clarify these two things for me and don't hesitate to elaborate if you like. Quote Link to comment Share on other sites More sharing options...
007 Posted December 9, 2004 Share Posted December 9, 2004 I would just buy a second cs-ultra and take advantage of the other 1/2 of your amp. Quote Link to comment Share on other sites More sharing options...
formica Posted December 9, 2004 Share Posted December 9, 2004 ---------------- On 12/9/2004 3:21:32 PM Seismic_Pulse wrote: Could someone clarify these two things for me and don't hesitate to elaborate if you like. ---------------- I think the "physics" you are missing to make sense of it all is Hoffman's Iron Law. It's a fundamental design principal that applies to all low frequency speaker design. In lay mans terms... it states the bass-extension, efficiency, and enclosure size are all directly related and improving one will hurt performance in the other two. - Lets say you want a small enclosure to fit in the trunk of your car... well you'll have to give up bass-extension and/or efficiency. - Lets say you want to improve bass extension... well you'll have to give up efficiency and/or enclosure size. Car audio is very size limited. Home audio is less so, unless your significant other says otherwise. Sunfire and SVS know this well... no black magic. As i've often posted... it comes down to which compromises you are most willing to live with. Any questions? Rob PS: My next planned sub will compromise SIZE (it'll be about 800ft3) to maximize efficiency and bass-extension. Quote Link to comment Share on other sites More sharing options...
avklipsch Posted December 9, 2004 Author Share Posted December 9, 2004 Does anyone have Tommy v's e-mail, or has he discontinued using that? I checked the website. I can't seem to find it anywhere. Thanks, Aaron Quote Link to comment Share on other sites More sharing options...
Olorin Posted December 9, 2004 Share Posted December 9, 2004 STL, 10 feet square by 8 feet deep? Sounds like an IB to me. Hmmm . . . which, incidentally, could be AV's answer as well, depending on the WAF for holes in walls, ceilings, or floors . . . sell the SVS, keep the Samson, get four Tempests, and involve the entire neighborhood in the HT experience. Quote Link to comment Share on other sites More sharing options...
avklipsch Posted December 9, 2004 Author Share Posted December 9, 2004 Hmmmmmmm, Tell me more!!! AAron Quote Link to comment Share on other sites More sharing options...
Olorin Posted December 9, 2004 Share Posted December 9, 2004 http://home.comcast.net/~infinitelybaffled/ Enjoy. Quote Link to comment Share on other sites More sharing options...
meuge Posted December 9, 2004 Share Posted December 9, 2004 ---------------- On 12/9/2004 12:21:37 AM killerbee_vr6 wrote: Which completely explains excellent low-bass performance in cars and with headphones. ---------------- I am not sure I understand your post correctly, so tell me if I am wrong, because it seems as if you're being sarcastic. If tat is true, then let me offer you evidence to the contrary. Car subs are terribly inefficient and require huge amounts of power input, large magnets, and huge excursions in order to reproduce bass for the reason that I mentioned. Furthermore, they are usually tuned to a certain frequency (or a narrow range) within which they are efficient, based on the size of the car. I am not quite sure about that, but I doubt that there are many car subwoofers which will go down as low as HT subs. They are meant to punch and the best punch is between 40 and 60Hz. Because of the space constraints, other waves will be subject to self-interference and interference from their harmonics, which will probably lead to a horrible frequency response curve unless the car sub is heavily equalized. As for headphones, they are another beast altogether. Because they do not need to fill a space with the sound, they act as simple direct radiators - hence their decent bass reproduction. For this reason headphones have requirements that are similar to speakers that are meant to perform in an anechoic space. Since the distance between the tympanic membrane and the speaker is so small (let's say 3 cm), then the only frequencies that'll suffer from interference will be those above 11kHz or so. The other waves will not be subject to interference, since they will not fit within the chamber anyway. So they'll be less efficient, but equally so, resulting in a very flat frequency response all the way up to the first wavelength that fits within the chamber between the headphones and the ear. Open headphones will have an even better response curve, since the waves that fit within the chamber will only bounce once and then dissipate into space. Quote Link to comment Share on other sites More sharing options...
InnovaZero Posted December 10, 2004 Share Posted December 10, 2004 Accually because car subwoofers are built to accomidate a car's small size, they do well in their environment. The waves in the trunk, and throughout the car will reinforce themselves. This is why with in lab tests, a good car sub will reach 15hz with ease, where as you bring into a HT-like area, and it has trouble with anything under 40hz. This also effects the incredible SPL gain they grab from the cabin that is the "Trunk" outside of their respective enclosure. Quote Link to comment Share on other sites More sharing options...
CAS Posted December 10, 2004 Share Posted December 10, 2004 ---------------- On 12/10/2004 10:43:29 AM InnovaZero wrote: Accually because car subwoofers are built to accomidate a car's small size, they do well in their environment. The waves in the trunk, and throughout the car will reinforce themselves. This is why with in lab tests, a good car sub will reach 15hz with ease, where as you bring into a HT-like area, and it has trouble with anything under 40hz. This also effects the incredible SPL gain they grab from the cabin that is the "Trunk" outside of their respective enclosure. ---------------- True statement. Even though my PB12+2 is very effective, it can't hold a candle to the response I used to get in my auto. At full volume it was not tolerable within the car and performed outstandingly well under 20 Hz. I measured SPL between 140 and 150 dB with two 12" drivers. Quote Link to comment Share on other sites More sharing options...
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