Someone More learned: Help

DanielCSCS

I am in the midst of a debate with myself. I certainly don't need a sub considering I am a Condo owner. I am however fortunate, that my dwelling is extremely well made and insulates sound very well. My neighbors, when asked have never reported any disturbances coming from my home.

Honestly, here is my greatest delema. After hearing a pb2-isd for the better part of what has been two weeks, I can sincerely say that I don't want that much low frequency in my home theater? I do not like feeling earthquakes every time LFE signels are produced. Secondly, I am not particularly pleased with the aesthetic offerings from SVS and Hsu as they currently stand. I understand that performance is the selling point for these companies.


Here are my questions, and I would appriciate articulate answers if they can be provided.

1. Is there any truth to the notion that ported subs contribute greatly to whats felt in low frequency effects? I want to hear more and feel less, it was my impression that the PB2-ISD value is best measure with a rictor scale and not the human ear.

2. How does the size of a sub's driver affect LFE signals produced in todays dvds? I believe I am on the verge of understanding. From what my research has shown me, given my particular tastes it seems like I would enjoy a acoustic suspension design. I enjoy accurate deep base in music, but i don't particularly like the garbled rumble that the pb2-isd produced in film.

3. Would a sub like Pinnacle's Baby Boomer satisfy my desires? I am obviously prepared for this sub to fall short in total SPL and Frequency response, but in a 25x15 room that may be all I need.

dave shepard

I'm sure Doc will chime in with better recomendations but untill then plug the ports that I believe will raise the sound and reduce the felt bass and adjust the crossover and phase you should be able to get it just the way you like and need. SVS makes very good adjustable subs to fit every taste and need. Going from 0-180 phase will effect the felt bass 180 phase should reduce the amount of felt bass.

gatemplin

I am not an expert but I'll try to help.

1. Yes ported subs contribute to the LFE because these are often at or near the subs tuning frequency.

2. Acoustic suspension designs are said to be very accurate but so are SVS's if that is what you are asking.

3. I looked at the Pinnacle. Seems ok but not for the money. I think that a Adire Audio Rava (sealed) would be better for half the price.

Also Dave, I believe that the sub's variable phase switch is designed so that the sub will blend well with the mains regardless of where the sub is placed in the room. As far as I know phase is simply timing which should have no effect on output.

Dr. Spec

Have you calibrated the sub?

Experimented with placement?

Experimented with different tunes?

That sub is exceptionally accurate. Either it is running too hot, or poorly placed, or both.

ANY sub will sound like **** if it is not properly integrated into the system.

How is the sub set-up in the room and what are all your bass management settings and what is your calibration method?

dave shepard

Originally posted by gatemplin
I am not an expert but I'll try to help.


Also Dave, I believe that the sub's variable phase switch is designed so that the sub will blend well with the mains regardless of where the sub is placed in the room. As far as I know phase is simply timing which should have no effect on output.

I was thinking, if his sub is too much then that might help so it doesn't pound over the speakers. I could be wrong.

gatemplin

"I could be wrong"

So could I. Maybe Doc can give a better explaination.

Dr. Spec

Not much more to say here until he gets back to us. Could be phase related, but seems more like a placement and calibration issue. Corner loaded and running too hot might be the primary issue.

DanielCSCS

Doc, I don't doubt that more could have been done within the living room of my best friends house. He was the gentlemen who purchased the PB2-ISD. His living room is approximately 20x13, paritioned with a false wall that seperates the kitchen from the livging room. This wall doesn't completely seperate the kitchen from the living room as it's height is approximately 8 feet and of course the cathedral ceiling is well towards 20 feet.

We experimented with 5 different sub placement positions. Those positions were amidst and around the living room furniture. As it was our goal to make 115lbs of subwoofer as inconspicuous as possible. That of course was a rousing failure, but that goes without saying. In each of the five different positions, 3 of which were corner positions, we kept the sub tuned at the 25 hertz position. Is that not all ports open?

We experimented with various axis positions, that is to say we moved the sub's ports away and towards the wall and couches. We finally determined that the best sound came from the sub being positioned mid room, adjacent to the couch approximately 10 inches from the wall, to the subs left. With the exception of the couch to the immediate right of the sub, nothing was obstructing it's operation.

The pb2 was attached via LFE cable to a 43TX and all Axiom speakers were set to small, including the m60 towers, with universal crossover setting of 80 being selected. Base peak limiter was of course disabled, but in retrospect I wonder if doing so did not contribute to our delema.


Gentlemen, my experience with base is sincerely limited. I of course intuitively know what good base sounds like with respect to music. That is to say, I know what sounds ghetto and what doesnt. I trust no one will assume me biggoted by that comment.


The overwhelming pronounced effect that we experience from this subwoofer and our two primary reference material was physical it was tangible. We felt wayy to much. Then when base was audible it was so overwhelming I felt like I was in the middle of a club. Now, if Im not mistaking we set our subs test tones approximately 5 decibles higher than our balanced test tones using our trusty Rat Shack SPL meter.

Let me elaborate further, when we tested Blade II some of the very pleasurable effects we noted was the added depth the film assumed. Even the dialogue seemed richer. Ok, thats great. His gun shots were deep and yes they seemed to punch you in the chest. The house of pain sequence, the music played as they entered, was dance club loud. All those sequences were pleasurable, they were excessively loud do to my buddies need for -10 volume setting, but to an extent pleasureable.

Lord of the rings, on the other hand was...... like sitting on a Harley davidson Fatboy without the sound. Nothing but annoying room shaking; It seemed like excessive annoying room shaking.
This may be a desireable result for many of my fellow home theater nuts, but as far as I am concerned its just "too much". For example, do all of you recall the portion of the film where Isildor is holding Sauron's freshly cleaved ring finger? Recall, that the finger all but turns to dust in his hand. Now, that sequence when heard without a sub, has a detailed sound all it's own. I can liken the sound to that heard when light footed steps are taken on fresh snow. I know, I know, that sounds ****, but check it out yourself its a detailed sound, which was by the way all but invisible to me while I has my entry lvl Sony POS driving my polks.

So, then were fire up the PB2, during that exact sequence whats experienced is of course the vibration eminating from the sub, and poof the detail of the film is lost.

So, that brings me to my point. What if anything can be done about the audible potency of a powerful, large, heavy, voice coiled 12" sub to reduce this effect? Laugh, my good men, but I like the base produced by a pithy rti100. I like the quick reflexes of a powered sub equipped with smaller driver(s). I don't suspect it necessary to appriciate clear detailed base within a home theater setting with a sub capable of leaving our ears ringing from the experience.

So, my ultimate questions for those better experienced than I, is what should those of us who dont want Dance Club SPL potential from a powered sub purchase? What sub would fit those of us that don't want our drywall damaged by overwhelming ground shaking vibration. What sub should we look into if even the entry level offerings from SVS and Hsu just wont fit living room decore?
What subs out there will fill in the gap appropriately when many of our Polk fail? Whats going to be accurate and pleasing in the 30-50hz range that will provide added texture and warmth in an already relatively well textured and warm sounding HT?

dave shepard

Sorry but that has gotten over my head and don't know where to take ya. If anybody can it would be Doc.

Good luck
Dave

gatemplin

If you like bass in the 30-50 Hz region then almost any ported commercial sub will do. Check out the Polk subs, Paradigm or go the DIY route if apearance is an issue. These smaller subs will not produce better quality bass just because they are small though.

I believe that the sub is running hot and placement or tuning could be better but I understand that you have other priorities. The pb2 should be very accurate though. Maybe try recalibrating or Doc Spec may see something you did wrong. Take his advice.

shack

The Dayton Titanic 10" sub kit from Parts Express may be what you are looking for. It is a sealed design. Read about it HERE

It won't play as low and loud as many of the bigger versions from SVS, HSU or Velodyne but it is a nice, relatively small sub that goes pretty low. It also really integrates well with my RT55is in a 2 channel w/sub arrangement. You don't know it is there until you turn it off and notice that the low end fullness it missing. The 55s do very well on their own for stereo but this little sub adds a lot. I can easily recommend this to anyone that wants a quality sub at a reasonable price. I've had this one for about a year and a half and have no complaints. It isn't beautiful (it has a black crinkle finish that is ok - I would have preferred a gloss finish) but it doesn't look too bad. It does an admirable job with movies. The sock explosion in Monsters Inc. and the opening scene with the cruiser approach to the city in Star Wars ATOC (sub reference DVD scenes I like to use) are handled with ease.

HERE is a review you might like to read.

Yes, it is a kit but really easy and fun to put together...It took me a little over an hour.

I've also heard that the Adire Rava is very similar in performance and only slightly larger with a 12" Woofer. It is not a kit and can be had in oak or black for a little more $. I was actually going to order the Rava but they were out of stock so I orderd the Dayton instead.

Here is a pic of mine so you can see the size ...

shack

Another view so that you can see the size relative to a RT55i and a 32" TV...

Emlyn

In terms of just adding bass warmth to a system of Polk speakers, I'd suggest settling on a smaller subwoofer like a Polk or going without one altogether and relying on full range main speakers to handle LFE. The SVS PB2-ISD is capable of putting out phenomenal effects in a medium sized room. I use mine only for movies and multi-channel hi-res audio because close to full range sound is produced by my RTi150s for music.

After tuning my PB2-ISD this afternoon to 25 Hz (all ports open) and calibrating it even with the other speakers in the system, I played my favorite LFE demo disc (The Haunting DTS-ES) and was literally blown away. That movie is filled with remarkable rumbling sound effects from beginning to end. One may find a PB2-ISD more mellow simply by turning down its gain and calibrating it below the level of the other system speakers, but then one really shouldn't buy one in the first place. A subwoofer will not make ears ring--excessive high frequencies do that and are caused by turning overall system volume up too high for comfort. Even with calibrating a subwoofer low though it is hard to ignore a 115 lb rectangular black box sitting mid-room as your friend's was. These things aren't for everyone. Mine fits in a corner of my 20x13 HT room and looks smaller every day now.

Have you considered a PB1-ISD or the upcoming PB1-Plus (real wood box)? Remember though that a subwoofer is not a requirement to enjoy home theater. You may be happy in your apartment with main speakers (powered by a good amplifier) handling LFE if you want to get larger main speakers than the ones you're using now.

Good luck on your choices.

Dr. Spec

I'm hearing (reading) two things here, Daniel.

1) You are running +5 on the RS meter for sub calibration. That is actually +7 since the RS meter reads low. For starters, turn the sub volume down 5 dB so it reads FLAT on the meter. That will actually be 2 dB hot.

2) This sounds like a living room with a large wooden floor over an open space? Let me guess - you can feel the sub working through the floor? Also, jump up and down on the floor and tell me if it makes a deep booming sound that can be felt and heard throughout the house.

Large wooden floors are NOTORIOUS for introducing excessive vibration and their own booming resonance when coupled to extremely strong downward firing drivers like those in the PB2. I've seen a PC+ turn a cheap wooden floor into a literal trampoline - it sounded terrible until we decoupled it from the floor.

If the floor is wooden and you can feel the PB2 in your feet, decoupling the sub from the floor is important. Have your friend try this first: Stand the sub on its nose so the baseplate faces the listener and the ports fire upward. Tell me if this reduces the coupling effect to the floor.

If it does, he can try buying two $8 reinforced concrete air conditioner pads and placing the ISD on them to decouple from the floor. They should reduce vibration transmission and booming considerably.

If this is a wooden floor, trust me, they are the anathema of good bass. I completely disagree with anyone (including the sound pros) who build a wooden floor over concrete to increase vibes. They sound like **** compared to the tight, resonance free sound of a concrete slab floor. The only thing the sub should be moving is air - not the floor.

Hope this helps.

Doc

dave shepard

Originally posted by Dr. Spec

If this is a wooden floor, trust me, they are the anathema of good bass. I completely disagree with anyone (including the sound pros) who build a wooden floor over concrete to increase vibes. They sound like **** compared to the tight, resonance free sound of a concrete slab floor. The only thing the sub should be moving is air - not the floor.

Hope this helps.

Doc [/B]

Doc, with all your recomendations you have given me and all of them I have followed is that a subliminal message ment for me given my house is 95yrs old?:D

Dave

Dr. Spec

Not really directed at anyone else. But yes, try decoupling the sub from the floor and see if it tightens up any.