Why IB Sub?

**Phil M** · **07-01-06, 09:52 AM**

This question is to help me, and others, understand the benefits of an IB sub.
Looking at the posts and links the only benefit I see is to remove the need of having a sub taking floor space in your HT room, freeing up more floor space.

Could you experts help the rest of us understand more - is this the only benefit?
Also any downside with an IB?

**brucek** · **07-01-06, 10:12 AM**

I don't know much about them, but one disadvantage that I could see would be sound levels in the rest of the house (if you're using an attic IB). With a conventional sub, the sound is contained in the theatre. With an IB, the sound would be available to the ceiling of every room, unless it was in a contained attic section.

Advantages would be low frequency extension since the cabinet size is huge. We hear of responses easily extending to 5Hz. The distortion would then be quite low.

I would think that the entire project is fairly cheap compared to retail subs.

brucek

**Sonnie** · **07-01-06, 11:34 AM**

Cheap? Well it can be I suppose... not everyone is as insane as me. Mine will run $2500 once it's all said and done. That's about what my two SVS subs cost. It might be a little less depending on if I end up needing a x-over and/or two amps.

I never had a problem with my Velodyne HGS-15 traveling throughout the house and Angibug complaining... but with my two SVS subs... if she's at home she's gonna have something to say when I take a pee-pee break or get done with the movie. I know what she means too... when Chelsea and her friends are out there and we're inside, it's unbelievable. It sounds like some serious thunder. I could hear faint thunder in the distance with my HGS-15, but again not a problem. With the two SVS subs... it's like right on top of the house... loud. Every now and then something will shake or rattle. Angibug made the statement one time that the house was gonna fall apart one day because of that room. Maybe so with the IB's.

Darren stated his IB is not really any worse than his regular sub, but he has a lot of insulation in his attic too. ThomasW has recommended I put insulation in mine.

Anyway... I'm getting somewhat off topic.

My reasoning for trying IB is to get the supposedly ultra clean low response down to 10hz or so, but I've heard on more than one occasion that IB doesn't always have the same impact as some traditional subs. But then I've heard it can if you do it right and have the right conditions.

You ask for experts, why did I even chime in?

I think Chrisbee has a way with words that describes IB like no other. I'm sure he'll chime in and share it with us.

**Phil M** · **07-01-06, 01:07 PM**

Thanks guys, I'd like to see this post run out so more replies the better.
Then hopefully the tweakers amongst us can weigh up the options of doing it or not.

**Darren** · **07-01-06, 01:10 PM**

I'm not an expert but I can give you some info. I have a 4 way 15" IB.

1. Very few have reported any more noise in the surrounding rooms or outside the house than when they had a traditional box sub. Me included, no extra noise anywhere.

2. The sub is hidden and takes up zero space in the room.

3. Mine plays flat to 10Hz, has more output than my box could muster (AV15 PR'd), actually has more tactile feel than any sub I've ever heard/experienced. My entire house shakes between 10Hz and 20Hz sweeps. I also get the chest pounding sensation when appropriate.

4. The only down side I can think of is the absolute need to EQ the sub. With the EQ you can make it behave any way you want.

5. More drivers, more efficiency = fewer watts.

6. The cool factor is very high. Especially when nobody can figure out where the bass is coming from.

7. With multiple drivers playing in an IB you get much less distortion, the bass isn't colored, it integrates with my mains quite well.

8. Placing the IB between the mains is much easier than placing a bulky box sub between your mains unless you have a dedicated space for listening.

9. HUGE WAF if you can get past the hole cutting

With EQ my sub hits 10Hz without loss of output, I can't measure down to 5Hz so I can only assume that it has pretty decent output there but probably drops of a little. I'll be spending up to $1,500 for a 4 way IB once I have my final drivers. I could have one that is quite adequate for a 3,200 cubic foot room for about $700 but I want high excursion, not moderate so I'll probably be going the more expensive route.

For more info you must check this IB FAQ out: http://home.comcast.net/~infinitelybaffled/

**kingkip** · **07-02-06, 12:25 AM**

I also have a 4 15" IB and the performance is incredible.

Flat to 10 Hz and very clean sound. In fact I thought I built it for HT but I am finding myself listening to 2 ch more since it has been up and running. The sound is different then a traditional box, and it takes some getting used to, but once you do there is no going back. The IB is subtle but forcefull. It will hit very hard when it needs to but is not boomy at all. At first it almost sounds wrong, but then you start to realize that is how stuff was meant to sound. Really really cool.

**Jack Gilvey** · **07-02-06, 09:02 AM**

Just an observation that occurs to me when I see a reference to IB "vs" sealed: An IB is a sealed sub (albeit one without an obvious "box"), in that it relies solely on the drivers for output and the back wave is isolated from the front. It has a large efficiency advantage (and less thermal compression) down low from the very large Vb, a typically very low Qtc, and no acoustic high-pass filter in the form of a stiff airspring behind the drivers. Also, since box size is not a restriction, IB-ers usually find it much more easy to incorporate large amounts of displacement, four 15's is fairly common. This has nice gains in dynamics and distortion as you might expect. I think this huge Vd is a large part of the epiphany many experience when they first fire up their IBs...a single 12 to four 15's is a bit of a jump.

The obvious disadvantage to me is the probable lack of placement freedom.

**Chrisbee** · **07-04-06, 04:00 AM**

Quote:

Jack Gilvey wrote:

The obvious disadvantage to me is the probable lack of placement freedom.

Tell me about it! I'm not even allowed to put a manifold in the roof that I put on myself. (working alone)

She doesn't mind giant round holes in the walls but she won't have square holes in the boarded ceiling. In case it rains in?!?

?!?

I have plans for manifolds in the roof access hatches I put in at the same time I built the dormers.

A shame they have 16" of rockwool resting on top of them!

I may have to go in from above!

Oh, you meant acoustically?

**jagman** · **07-29-06, 01:55 PM**

I have a dual Avalanche 18" IB, and am quite happy with it. The sound is clean and sharp, but also forcefull when needed. I dont' have an EQ yet, so my frequency response is not ideal. I think I'll be much happier after I finish my passive acoustic treaments and get the BFD. My room is about 3000 cubic feet, but it has a door sized opening to the rest of the house (>10,000 cubic feet). My response slowly drops off below 30 Hz (indicating little if any room gain) so I think I'll end up installing a solid core door with weather stripping... partly to re-enforce the bass and partly to keep the sound down in the rest of the house. The opening happens to the rest of the house happens to be in the front left corner, so a lot of bass is escaping. I also have 57 square feet of windows in the room

. The other problem I have is I'm already pushing my amp to its limit (350 watts per driver). I have a feeling I don't have enough power in reserve to boost the lower frequencies once I get the BFD. In summary, the IB gives a very natural sound, and is very pleasant even without EQ. As indicated above, my setup is no where near complete... and I'm sure it'll be very nice once done.

**Chrisbee** · **07-29-06, 02:02 PM**

Quote:

jagman wrote:

The other problem I have is I'm pushing my amp to its limit. I have a feeling I don't have enough power in reserve to boost the lower frequencies once I get the BFD.

I'm sure I remember Thomas saying that the VLFs are very easy to drive.

That said, power really makes an IB come alive, at least in my own experience.

**jagman** · **07-29-06, 03:33 PM**

I hope you and Thomas are right. One would think the Aves would handle the low end easily. It'll take some time to finish the room treaments. Unfortunately time is hard to come by right now. We'll see. I don't want to EQ until I get the treatments up as they will likely come in slowly over the next few weeks to a month. Unfortunately that means the room response will constantly change. I'd rather use the time to make the traps/absorbers instead of using it to take measurements that won't be valid the next day.

**Chrisbee** · **07-29-06, 04:44 PM**

I'd be using the time to enjoy the IB. The room treatments can wait!

**Derek** · **07-29-06, 10:40 PM**

Finish those bass traps! They will make a huge difference. I don't know if it's the IB or the room treatments, but my system sounds much better than anything I've demo'd in the local high end stores. Bass is well defined and sharp. Powerful when needed (i've worried about the drywall cracking while showing off).

Why IB? Effortless sound. Crisp transients. No hint of boomyness or muddiness. Music sounds so much more real. The upper bass/lower mids sound cleaner.

http://home.earthlink.net/~afordfan/id1.html

**jagman** · **07-29-06, 11:34 PM**

Chrisbee... I hear you man. I've had the IB installed since December, though, so I've been enjoying it for awhile. Now it's time to make it even better. I have had the vertical and rear wall bass traps in for a couple months and they definitely help. I especially noticed the difference when I took them down to paint the room. There was a major difference. I lined the side walls with the 8# mineral wool just to see how it would affect stereo playback... and I noticed a surprising amount of increased clarity. I was rather doubtful going in, but pleasantly surprized. I would imagine first point reflections will do even better with 3# compressed fiberglass (better high frequency absorption when not hit straight on) than the 8# material. We'll see. The nice thing for me is nobody else I know is an audiophile by any standard... which means I'll optomize the sound for my seat and nobody will notice the difference in theirs

.

**rlammi** · **08-01-06, 06:20 PM**

As stated in the previous posts ,they are cool ,but for me it came when I was playing music be it Pink FLoyd or Metallica they stayed right with the bass without any effort .I am using 4 12's from Gr-research ( I know there are better drivers out there) I had a hard enough time selling what I have to the wife .Mine are attic mounted in a manifold centered above the plasma .I tried my old sub and then with the I/B and it was night and day difference and then try turning the sub off even at lower volumes and it is amazing at the output of an I/B .Some day I may jump up to 15's but I don't have a super huge room so for now the 12's will do just fine .Once I have time to finish REW and get the BFD dialed in it should help alot .As for noise through out the house it is actually less ,granted you can still hear/feel the bass at hi volumes ,but the attic has a ton of insulation ,also for the big sealed box my manifold is about 10-12 feet away from a vent that is 18'' x 24'' so it isn't totally sealed .As for sounds outside I have played both the old sub and the I/B and there really isn't much difference .The best thing about the I/B is if someone doesn't know it is there they are really impressed with the mains

My brother came over and wanted me to play some of his death meatal crap to compare it with his bose

system and it rocked his world .I may now be biulding another I/B .I now notice jagman is in Sacramento we may have to try and hook up and compare systems and note.All I can say is I am hooked and need some AA help according to the wife .Take it easy all and I will keep everyone updated in the BFD/REW thread I have if I get some time to run it this weekend .Ron

**Chrisbee** · **08-02-06, 03:57 AM**

People will argue about quick or fast bass until the cows come home. Usually because they are fans of small sealed boxes. Despite its bottomless extension the IB has no hangover so it really is fast. The fascinating thing is that you can hear exactly how a sound starts, is sustained and then decays in the very briefest of moments. No other sub I've heard can do this. In comparison, most other subs sound a like a range of large cardboard boxes being beaten by a stick then over-amplified. The distinctive "boxy" AV subwoofer sound you hear in every room and hall at every AV/HT show and in every dealer's demo room. Brutally loud and impressive maybe, but so artifical, so second hand, so muffled and so lacking in real detail.

It is instantly noticeable when an IB is playing the bass on music. Percussion immediately stands out by sounding very deep and very real. If you have a solo percussion CD and let the IB loose you will be shocked by the frightening dynamics, depth and realism. You will flinch back from drum hits that sound literally a few feet in front of you. So sharp and quick and so LOUD! The shortness of the blow is so unxpected. So brief. So instant. So out of nowhere and so quickly gone again. It leaves you totally unprepared before you are being shocked again.

When the ring finger drops in LOTR it feels exactly as if a heavy hammer strikes the floorboards beneath my feet. Short and hard. Bang!

If I was forced to choose a single word to describe the difference between any other sub I've ever heard and an IB. It would have to be that that the IB is, quite simply, realistic. You can't ask for more than that.

**toecheese** · **08-02-06, 06:49 AM**

The best thing to do is read the FAQs on the cult website. They go into a lot of detail as to why an IB is superior, but I'll summarize.

Pros:

'cleanest' bass possible (sorry, but it is true- purity of bass can only happen in IB)
Relatively low cost
Low impact to room

Cons:

Custom installation
Less bass 'power' (at a given wattage)
Time to implement

I read about it for a while, saw a couple of guys do theirs. When I finally got around to doing it, I was blown away. It is not 'rattle your teeth' bass (like the guys who have mono-frequency 'kickers' in their trunks) but dare I say... beautiful bass. And with the proper planning and design, it can kick your teeth in too- without the distortion.

People who have heard my system agree that it is the best bass they've heard.

Some info on mine on http://farzanegan.org/ht (look for entries about IB)

**rlammi** · **08-02-06, 09:14 AM**

I agree with chrisbee ,they can handle any bass that is thrown at them ,and as for HT they are totally impressive .Again I am still in the process of eqing mine so I am sure it will get better ,but the I/B has impressed me from the rime I fired it up .chrisbee what is the percussion cd you have and can it be bought ?
thanks all I/B's rock .

**Darren** · **08-02-06, 09:27 AM**

Yup, all of the above and just as a point of reference I get HUGE teeth rattling bass in my current setup:

Four RL-P15's with an EP2500 4 ohm stereo (325 watts per driver) in a manifold above my plasma in a 3,200 cubic foot room which is open to the rest of the house.

I get pelt you in the chest bass at much higher and lower frequences than with my box sub. For instance, the gatlin gun on the Matrix scene where Neo is shooting out the windows of the building so Morpheus could jump to the helicopter. I feel the blasts in my chest. I used to have impressive impact with that scene but my IB is moving a lot more air at 16 liters so I feel much more of the effects.

Also, with my box sub rock music was really lacking in the bottom end and if I cranked my sub it would just add muddy bass because it was artifically added. With the IB I can crank the music and switch my BFD to my prefered curve for Rock and really FEEL the music

Much better integration with my mains, when you hear a bass guitar you hear the note begin and end rather than hear a frequency produced as it used to be. You hear the pluck and the vibration... not just the frequency. With the kick drum you hear the drum itself, not just a thud.

**Chrisbee** · **08-02-06, 02:14 PM**

Quote:

rlammi wrote:

chrisbee what is the percussion cd you have and can it be bought?

The Percussion CD I have is by a Danish percussionist.

Whether still generally available I haven't a clue.

BIS CD-256 Grammafon AB BIS (Sweden)

Nørgård, Per "I ching".

Xenakis, Iannis "Psappha"

Gudmundsen-Holgreen, Pelle "Tryptykon".

Gert Mortensen (Percussionist)
The Danish Radio Symphony Orchestra.
1981,83,86 & 88

I found mine in a used record store.

**Vaughan Odendaal** · **08-02-06, 02:30 PM**

Hi guys,

I know this is asking a lot but I want all IB'ers to play these three demo scenes for me and then to report back. I consider them great material especially if your system has the power and the right dynamics. The first demo sequence is from the Matrix Reloaded, the "Burly Brawl".

There are lots and lots of deep bass hits in the fight scenes. Different kinds of bass sounds are present in this sequence. From very low to high, different tonal qualities, timbre changes, etc.

The second demo sequence I want you to test is from the Matrix Revolutions. Towards the end of the film, the machine speaks to Neo.

The machine utters the word "SPEAK" in a monotonous voice. This has some ultra deep bass down to below 10 hz. Please try that one out.

Last demo sequence is also from Matrix Revolutions. The final fight sequence between Neo and Smith. In the beginning fight in the street, there are times when Neo and Smith connect punches when all of sudden lightning strikes. This material has high amplitude 18 hz bass contained in it.

The rest of the fight has various sub-15 hz bass throughout. Various kicks and punches have deep bass in them too. I have found these demo sequences to be quite demanding on subwoofers because if they aren't reproduced properly, you'll get overhang, a boom-boom tonal quality and definite compression at high levels.

Most people here seem to have setups that have very high Vd. So please play those scenes for me and report back with your opinions.

Thanks. BTW, my PB10 ISD kicks ***. Um. . .

--Sincerely,

**Darren** · **08-02-06, 02:34 PM**

I just recently listened to the "speak" scene and it is indeed very deep. Reproduced very well with no strain at all. I'll try and demo all the scenes you requested tonight if I can.

**Vaughan Odendaal** · **08-02-06, 02:39 PM**

Thanks a lot !

--Sincerely,

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