For those who have listened to IB subs.... - Page 8

Good luck with your relationship.


Because ThomasW doesn't understand your claim. Several dozen 18"s wouldn't matter since they would effectively be dummy drivers and wouldn't offer any benefit since the required Vd to reproduce signal peaks in whatever program material you watch would have been achieved with the 4 15"s since they too would be hardly moving at all.

See, if you have enough Vd for the program material and listening level then adding more Vd will not make one bit of difference. Not one iota. Not one ounce. Not a bit. But you are claiming the contrary, that adding extra woofers somehow creates additional dynamics at the same calibrated levels. You are not well, ChrisBee.

In another world your cookie cutter physics might make sense, but in this world it does not, will not and therefore cannot. And to top it all off, you love your mentor in ways that shouldn't be.

I don't want to mow, so I have been playing with the vibration/resonance factor brought up before.

To test my thoughts out I ran around the house with my guitar. Any solid surface will change the sound similarly. Wood, cement, brick, stone whatever. The more solid it is, the louder the additional components become. Carpet will prevent the transference until enough weight is added to nullify it's dampening factor.

A regular sub on a wood floor, or one that is really heavy and/or spiked on carpet has the potential to do the same thing. Likewise, the rigidity of the buildings structure would increase/decrease this effect in an IB setup.

What is interesting is that this could skew an individuals subjective conclusions either way.

The discussion has been that an IB sounds different than anything else. My claim is that two systems, sealed and IB can sound the same. One is not better than the other. I don't think you are going to be able to tell the difference between a sealed or IB system EQed to the same response.

Two people have talked about their comparison of their sealed system vs their IB sytem, but the sealed system never had a chance since it was up against a system that had deeper extension with higher SPL.

Now you're calling me skewed?

Congratulations on having discovered critical compression versus compliance. I managed this in my youth when I was experimenting with the isolation of microseisms from my DIY suspended turntables. The floppy eventually becomes the solid, doesn't it?

It's nice to see somebody actually experimenting instead of believing bøsso's dogma. Full marks and a gold star!

Early attempts to build an IB array resulted in the whole roof heaving and creaking on REW sweeps. Impressive but ultimately dissatisfying.

That would be the 4 Hz below 14 Hz would it? And the difference between dynamic peaks relative to speaker calibration. Why not just turn up the overall gain and claim it sounded deeper?

I should have been more specific. Same response and same extension.

I'm afraid that has nothing to do with the post of mine you quoted, or my posts and questions to you. Notice the wink here, and emoticons used in our other exchanges.

I don't know if you have noticed, but there are more than three different topics being discussed in this one thread. All going on at the same time, and some weaving in and out of different ones.

Hehehe... nah. Everyone has a 50/50 chance at this point.

The rest was nothing new to me, but if you don't have something to go with your words around here you can never get anywhere it seems sometimes. I didn't feel like measuring anything so it was more of a how too, for anyone who has to (see some work/do it themselves) to believe it. I'm trying a new tact here.

As I said, I didn't want to mow.

I'm very unhappy that ChrisBee decided to put me on ignore. I really wanted to understand what he was talking about but the word salad got in the way.

Shame on you ChrisBee, shame on you.

Yes there are, but you quoted me. I just was clarifying what I was saying. Of course before EQ there are differences. That is self evident since the response will be different.

I have only quoted you in post #139, and that was to say that you were on the wrong topic, using my words out of context when you originally quoted me (p136,) and to ask for more info on something you said about backwaves. This is also the post in which I asked you a direct question about non-EQed subs.

Post #140 is where you answered the backwave portion, but left the other question unanswered.

Hello everyone.
FOH = Front of house

I understand that I'm jumping in the deep end here, however this is a learning opportunity for me. My knowlege level in these areas is not nearly equal to the level of the vast majority of the contributors to these forums.

Let's get back to the very basics sound capture and reproduction. I have to keep things simple so this is my way to help me, and perhaps the OP, in a better understanding of the "Two Camps".

As we all know, every item throughout the recording/playback chain must accurately track the signal waveform. I suppose it's arguable, however... the transducers at each end of the chain generally must overcome the most physics of our environment, air in particular.

Let's examine the lower octaves, since that's the primary focus of the lively discussion here.

Now just as the low E string on an electric bass guitar vibrates rather freely at 41.2, or the foot pedal beater hits the highly damped head of the kick drum, and it quickly decays away, the transducers responsible for the acquisition must do so in as much of a linear fashion as possible. In the case of the bass pickup, the electromagnetic interaction of the metallic string modulating the flux of the pickup is, for our purposes here, relatively symmetrical. Now on the other hand, as an artistic choice, the kick drum head is asymmetrically damped...i.e. the beater side is unencumbered, but the interior of the drum is damped with some nasty pillow that the drummer pulled out of his gig bag. Therefore the mic that is inside, between the two heads, must as accurately as possible track the asymmetrically damped beater head of the kick drum as well as the overall tone of the two heads.

If one's goal is the exact recreation of the captured event, (either with substantial electronic manipulation or pure and un-adulterated, be it amplified for mass consumption at a concert, or recorded for playback in our homes and theaters at a later time), accurate replication of the end product is the theoretical ideal.

That being said, throughout the entire chain, the asymmetrical waveform and all it's components must be maintained, and upon playback..., must be replicated as precisely as possible. Ideally, polarity must be maintained due to the asymmetrical nature of the attack and subsequent decay, ...i.e., the leading edge of the kick drum impulse is a compression and not a rarefaction. Now different elements in the mix vary in absolute polarity importance. Some are distinguishable and most aren't. For this discussion, I'm referring to the theoretical ideal.

That brings us to the final transducers in the chain; which in this discussion are sealed subs, one being a relatively small box and the other being an IB. When the entirety of the moving parts, all coupled to... in this case a cone, attempts to precisely track the asymmetrical signal voltage, would both the IB and the small box react identically or would one have the advantage over the other? There are legions of individuals that feel that the IB has the inherent advantage due to the (relatively) symmetrical manner in which each side of the driver is loaded respective to it's environment. Whereas the small box sees the room air on one side and the significantly smaller volume of air on the other.

Do these two air load scenarios, which are at opposite ends of the spectrum, favor the IB? Are the frequencies affected by this asymmetry to high to be discernible? In my opinion, as the owner of a sealed 15" that's sealed so well as to slowly relocate back to the center position after being carefully pushed back into the cabinet against the air spring, that the IB would be able to track the macro and micro dynamics more precisely than my sub. However, is this an aspect that we can hear?

Can adjustments in EQ negate any of these aspects of asymmetrical air loading of the drivers?

In my opinion, theoretically, the IB has the distinct advantage in the ability to track the waveform. Is this valid at these frequencies?

I know, that's a helluva first post. I began to ramble ...sorry. I've lurked here long enough and learned a great deal. I wanted to lurk long enough to get the proper context on the contributors to these discussions. I've got an incredible amount of respect for a lot of what I've read and I am looking forward to learning a great deal more.

I, for one, think I'm going to build me an IB to see for myself. Might be while... but I'll do it.

Thank you

Got a quick chance in between my son and musician friends wailing away and every other sort of craziness that is the norm for this house to try a very crude measurement.

I set up the mic so it was very close to the same distance from the E string when coupled to the wall and decoupled from everything. I plucked the E string when coupled and decoupled and plucked it again, using every ounce of experience to pluck with the same force both times.

Here's the spectrogram:


Here's the bar graph comparo, animated:


I see what I heard. As I've described it before I had such awesome tools, the decoupled pluck is tilted to the higher end, the coupled pluck is tilted to the lower end.

It may be completely insignificant, but it seems like a start of something that may be fleshed out to an actual subwoofer measurement, eventually

Bosso

I think there was a post in this thread about someone saying the midbass was lacking from the IB and I posted its probably the mains mismatching/ lacking.

Someone is on ignore...that is so wimpy!!

Can you post the wav file? It would be nice to play with.

Plucking the strings with the same force after the slight movement is a PITA.

If you get the chance you may want to try it with the mic ~1ft out from your pluck hand, and hover the bass right at touching the object. This way you only move a fraction of an inch. To me if I bend my head over into this position there is a very noticeable increase in volume, and not just the added warmth.

That was Bosso (post #170) where he mentioned that MKTheater said lacking mid-bass. Catapult quoted Bosso's post (http://www.avsforum.com/avs-vb/showt...0#post18796440) saying it was probably lacking mains. I was just pointing out that it was not lacking mains since MKTheater uses larger mains than 99.99% of the people here on AVS.

I guess quoted was the wrong thing to say. You were asking about comparing unequaled subs and I was just clarifying my position about them sounding the same was after equalization so that the both systems have the same extension and frequency response.

Have you heard an IB? Even just hearing one for a couple hours at some guy's house isn't really enough time to appreciate it.

How many people participating in this conversation have actually built and lived with an IB for awhile? I'm starting to get the feeling that some people are talking out of their ass.

You've noticed that?

You have raised a fascinating point here about driver area and further corroborates what I trying to discuss earlier. (but which was drowned out by harmonic distortion from the the small box crowd) Or "upper bass humping" as it is technically known here at AV Pseudo-science.

The Mk1 ass is a very small and crude driver indeed. With manually variable horn loading and highly asse-metric with relation to pressure differentials across the air/air driver interface. Being a pressure driven device it relies heavily on extreme levels of displacement and velocity.

The result is very high distortion and driver self-noise. Making it extremely difficult to reproduce identical, acoustic, output waveforms. The sonic signature becomes a constantly mutating variation of the vuvuzela (but is never true fidelity) Transients are almost completely absent.

There are obvious parallels here with the small box (asse-metric pressure) scenario. The sound quickly becomes a monotonous and irritating variation of a goneten circling a fly swat. It suffers form extreme ONBS. (One-Note Bass Syndrome)

Whereas the typical IB enjoys a very large driver area and faithfully reproduces everything wonderfully and mellifluously. With no added GM distortion and with great dynamic authority. It's "heavy", man.

That may fly right over a few heads.

I would definitely be interested to know who here is commenting on this topic with little or no actual first-hand experience of said topic. I don't make comments about tapped horns since I've never built one or even heard one yet.

Also, what was the configuration of bossobass's IB? Was it built properly? Were there any unresolved issues? Mine wasn't perfect out of the gate and I didn't make any broad statements until it was working as it should.

An IB is no different from any other subwoofer in that it exists in a finite space. A poor room will need attention whether one has an IB or any other subwoofer.

From my own experiments over several years now I find the IB forgiving of weaknesses in proportion but not so much in construction. The opposed manifold is the safest option for most builders.

The array requires much more thought and effort to work well. But rewards those who can pull it off well. I'm sure mass loading the surrounding area will pay dividends. Provided sufficient is applied to avoid delayed (out of phase) resonance of the mass itself. One must remember that an entire wall dwarfs almost all IB's radiating area. If the wall moves then signal and dynamics will be lost. EQ cannot magically bring back that which is missing.

This has probably been answered somewhere, but how high could an IB play?

Say I want to crossover my speakers at 80hz, would this pose a problem for IB systems?

Right now I find my system sounds best with an 80hz x-over with the subs running a bit hot if I lower it to 60hz it hasn't got as much thump/snap to the sound as it does at 80hz which I much prefer.

80Hz is the recommended crossover point for IBs too.

You may get away with a higher crossover point if you can arrange an IB centrally between the main/stereo speakers.

I agree with your experience with lower crossover points. Lower crossover points rob any subwoofer of a lot of impact.

3 years and counting.

Lets play that ass talking game though.

Have you guys heard the same number of drives in properly designed dual sealed designs with monster amplication?

How can you tell one side they are wrong when you have never head the others side??

Here is the point, There is NOT a measurement that will show a difference. We are DIYers and not audiophiles so we actually know measurements matter.

When you can produce a measurement proving an 4x18" IB, EQed sounds different then 4x18" sealed subs EQed with much more power then you can post something about.

I said it already early as a point to another comment about IBs lacking in the mid range. It was nothing to do with MK.

its post #30

Gathered from this discussion IB is the be all end all subwoofer design? We should quit building sealed, vented, horns if we can accomodate an IB?

Why would you put a blown, big block V8 in a lawnmower when you can get by with a lawnmower engine... and, the grass looks identical?

The wonderful descriptive subtlety of the English language allows one to discuss the subject endlessly without actually ever mentioning farting. The farting still exists but in some circles there is absolutely no need to mention it. Farting was not the subject of my post. I'm sorry you completely missed the (audio-technical) point but I am not responsible for other's interpretation. If one had to limit one's vocabulary and use of language to a level, so that all can achieve perfect understanding, we'd all be working for the BBC sports department.

Indeed we should. Though not all homes have adjacent lofts, cellars or unused rooms suitable for an IB enclosure. If nothing else IBs would reduce energy requirements and thus help to combat global warming. But that's even more off-topic than posting pictures of sealed cylinder, bar tables in an IB thread.

Chris,

I know exactly what the coment was...its was sarcasm back at you.

You want to contribute to AVS then contribute. You come on here in one thread ONLY beacuse you own an IB...whoopie. Defend away fanboy, defend away.

You will NEVER produce measurements that prove IBs are different then sealed designs when EQing and displacement equalizes output and response.

yes, I own an IB but Im not a zealot about it like yourself. Go back to the Cult if you want to have a circle jerk about IBs

btw, your mocking of Bosso's designs tell me everything about your lack of talent and skills. Since we are on the topic of mocking builds. Make real money someday then get a real room for your IB