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Subwoofer distortion


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28 replies to this topic

#1 of 29 OFFLINE   TristenEugene

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Posted June 07 2009 - 10:35 PM

My current sub (Creative S-750) works pretty good but, I have noticed some new movies with good sound tend to overtax it causing this flubbing sound. King Kong sounds very good at high levels. the floor and walls will vibrate. But! The newest Batman movie causes the bass to flubb bad! Is this because better sound on the DVD? In both cases the track was Dolby Digital EX.

Any advice on a Sub that can handle the newest, latest and greatest? Including DTS MA and DD True HD?

So? Down firing, active, passive radiator, multiple smaller cones vs. large, wattage, asymetrical cases vs. 'square',...

I listened to a HT setup using the Infinity Cascade Model 15 sub. This one has 4 6'' drivers. Really sounded good playing Journey to the center of the Earth and Pirates of the Carribean at high levels.

Anything on this? Mainly I want to stay away from that flubbing distortion. I listened to a sealed sub that was $800 bucks and it flubbed bad playing Indiana Jones at BestBuy.

Thanks in advance.

Jeff.

#2 of 29 OFFLINE   David Willow

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Posted June 08 2009 - 02:56 AM

The sub is probably trying to play something lower than it is capable. This could be dangerous for the sub - it could case damage if it does not have a built in limiter.

What is your budget and how big is your room?

#3 of 29 OFFLINE   Robert_J

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Posted June 08 2009 - 03:35 AM

Quote:
Originally Posted by TristenEugene
My current sub (Creative S-750) works pretty good but, I have noticed some new movies with good sound tend to overtax it causing this flubbing sound. King Kong sounds very good at high levels. the floor and walls will vibrate. But! The newest Batman movie causes the bass to flubb bad! Is this because better sound on the DVD? In both cases the track was Dolby Digital EX.
A "flubbing" sound can be anything from overexcursion of a driver, to port noise (applicable on ported subs only), PR over excursion (PR subs only), amp distortion, etc. Without more information I can't really answer with certainty. Every movie will have different sound and that is entirely up to the engineer who mastered the DVD and the sound effects crew.

Quote:
Originally Posted by TristenEugene
Any advice on a Sub that can handle the newest, latest and greatest? Including DTS MA and DD True HD?
There are hundreds. Like David asked, how big is the room and what is your budget.

Quote:
Originally Posted by TristenEugene
So? Down firing, active, passive radiator, multiple smaller cones vs. large, wattage, asymetrical cases vs. 'square',...
You have asked a LOT in a short sentence. Down firing vs. front firing - doesn't matter. Active - If you want an amp in the enclosure then that is active. I built a pair of passive subs and power them with an amp designed to power concert speakers. PR - same as ported without the port noise. Increased the cost but you can have a smaller enclosure. Cone size - Doesn't matter with a properly designed sub. A pair of 10's has the approximately the same surface area as a 15. Wattage - Google Hoffman's Iron Law. Enclosure - Shape doesn't matter with subs.

Quote:
Originally Posted by TristenEugene
I listened to a HT setup using the Infinity Cascade Model 15 sub. This one has 4 6'' drivers. Really sounded good playing Journey to the center of the Earth and Pirates of the Carribean at high levels.
What is your definition of "high levels"? What are your expectations of your new sub? Because four 6" drivers would not satify me. Dual 15's isnt' doing it for me and that's why I'm upgrading to quad 18's. My goal is a flat response to 5 hz.

Quote:
Originally Posted by TristenEugene
Anything on this? Mainly I want to stay away from that flubbing distortion. I listened to a sealed sub that was $800 bucks and it flubbed bad playing Indiana Jones at BestBuy.
Sealed subs have lower distortion (most of the time) but ported subs are more efficient down low. I like large, sealed subs because without an type of subsonic filter because they can reach down low. I'm using 15's that are similar to these. My system is flat to 17hz and can easily hit 120db peaks with no problem.

Whatever you decide, don't expect miracles if you go with a $100 budget. The laws of physics also apply so don't expect a single 8" sub to hit 120db at 15hz. Subs are all about trade-offs. We will help you find one to meet your goals and your budget.

-Robert

#4 of 29 OFFLINE   MaxL

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Posted June 08 2009 - 02:22 PM

Quote:
Originally Posted by Robert_J
My goal is a flat response to 5 hz.

WOW!

world peace? no.
cure for malaria?? uh-uh.
put man on mars??? i don't think so..

5hz... Posted Image

could be the cure for constipation...
HT: Marantz SR8000, PSB Alpha B fronts, Alpha C center, CSW Newton S200 surrounds, Martin Logan Dynamo Sub, Marantz DVD, Sony CRT TV

Stereos include vintage Sony receivers/amps into vintage AR and KEF speakers.

#5 of 29 OFFLINE   Robert_J

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Posted June 08 2009 - 11:27 PM

Quote:
Originally Posted by MaxL
WOW!

world peace? no.
cure for malaria?? uh-uh.
put man on mars??? i don't think so..

5hz... Posted Image

could be the cure for constipation...
You weren't present when I told my wife that I was cutting holes in the ceiling. All 3 goals above would have been easier than the discussion that followed. I had to show her online pictures of infinite baffle installs and that convinced her.

If four custom built 18's aren't enough, I still have two extra motors (magnets). I can build another pair of 18's. I just need to get a few other house related projects out of the way before I can install everything.

-Robert

#6 of 29 OFFLINE   TristenEugene

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Posted June 11 2009 - 03:21 AM

Dave, Thanks for responding. Budget? About $1500 for the sub. Room size? Living room is 20 by 30 ft. Office is 12 by 26 ft.

What do you think? Interesting what you said about the low freq. I am careful with my sub and when I hear this flubb, I immediately turn it down. What can I do about it? I mean, I need a good enough sub. Is the wattage capability the answer to worry free loading?

#7 of 29 OFFLINE   TristenEugene

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Posted June 11 2009 - 03:46 AM

Robert. Thank you very much! My budget,, Don't worry! I want good and I am willing to fork out for it. It's just that My ear is good for sound but my experience is not good enough. That is why I am here talking to you good folks. You asked what I meant by ''hi level'' Well, it was enough to shake the couch and cause other things to vibrate. Thats all I know. Such as when Kong roared loud. . Thanks for the info about ported vs. PR. Mine is ported. I read where the noise produced by ported subs is called ''chuffing''. OOook!
The sub in that HT setup that you said,, as I described it,, ''...wouldn't be good enough...'' for you. Let me tell you!! This sucker was 800 watts, had 4 6'' cones and it was in a room that had high ceilings, 20 seats,, the room was big and this sub sounded real good! Another setup I went and saw was at the Fountains mall in Roseville CA. A klipsch,, I forget,, Sub with one active driver and 2 other radiators in a tri shaped box/case. This sucker put out 2000 watts peak,,,.

Anyway. Is it true to say that low levels of bass are handled better with a ported sub? What is the thought about having one ported for lows and a closed PR type for high levels?

Right you are about the different levels of sound on different DVD's that have the same sound track (Such as DTS, es, DD ex etc. They can sound very different!

#8 of 29 OFFLINE   Robert_J

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Posted June 11 2009 - 05:38 AM

$1,500 budget and a large room. Manufacturer direct you should look at something from SVS, Elemental Designs or Epik Subwoofers. Among them they have dozens of models that you would be satified with. I'm a DIY guy because I could stretch that $1,500 budget into a pair of 18's with a pro amp and EQ. It would easily sound better than as well as crush a $10k JL sub in total output.

Subs are about moving air. Four six inch "subs" can't move enough air to be called a sub. Total surface area they are equivalent of a 10" to 12" speaker. Mechanically they are limited to about 12mm of excursion for the best ones. Klipsch can make some great speakers but their subs are not a good value.

Ignore wattage on subs. If you had read about Hoffman's Iron Law bragging about wattage is like bragging that your car gets 2 miles per gallon. Subs are a trade-off in design. Size. Extension (how low it plays). Efficiency. Pick 2 and the third is determined for you. If you want a small sub that plays very low, then it will be extremely inefficient. You make up for that by thowing thousands of watts at it. An entry level SVS sub is large and plays low. Therefore it only needs 300w of power to push the driver to its mechanical limits. Pro subs are large and efficient but they don't play low.

Based on that, a good 12", 13", 15" or 18" model sub from any of the manufacturers I listed above would probably satisfy you. My DIY sub will also shake the couch with ease. In fact it will excite every inch of the 5,000 square foot concrete slab my house is built on.

Finally, both ported and PR enclosures are the same. They are both Hemholtz Resonator enclosures. It's just that one uses a port and the other uses a passive radiator.

-Robert

#9 of 29 OFFLINE   David Willow

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Posted June 11 2009 - 06:06 AM

Quote:
Originally Posted by TristenEugene
Dave, Thanks for responding. Budget? About $1500 for the sub. Room size? Living room is 20 by 30 ft. Office is 12 by 26 ft.

What do you think? Interesting what you said about the low freq. I am careful with my sub and when I hear this flubb, I immediately turn it down. What can I do about it? I mean, I need a good enough sub. Is the wattage capability the answer to worry free loading?

My advice is listen to Robert, he knows what he is talking about. Posted Image

You can definitely get a great sub for $1500. Internet Direct is your friend Posted Image

#10 of 29 OFFLINE   ShanonS

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Posted June 11 2009 - 08:56 AM

I'll second that, Robert is THE resident expert on subs. He just coached me through repairing an 8 yr old sub. Helped me find the right replacement/upgrade driver for the existing box. When I started asking about it, he knew from the name of the sub what driver and amp it originally had from memory. Now we just need to compare firearms;-)

#11 of 29 OFFLINE   Robert_J

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Posted June 11 2009 - 09:51 AM

Thanks for the complements but it's just an obsession about part of this hobby. A LOT of things I have learned came from the real experts here and other forums. Dan Wiggins posts back in the archives should be required reading for all sub junkies.

And yes ShanonS my love of things that go BOOOM goes beyond subs. I'll send you pics when I can finally assemble my RRA 6.8mm CAR A4. Last I heard they were just missing 1 part before shipping my order.

-Robert

#12 of 29 OFFLINE   ShanonS

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Posted June 12 2009 - 02:19 AM

Cool. I don't have anything fancy. I have a basic stock Armalite A4(T), which I know for a fact is fairly accurate out to at least 600 yds even with light rounds. I had a one-on-one session with an ex Navy guy who used to train snipers that helped me sight it in after I got the scope mounted. He owns the range I went to, and I just happened to be the only one there so he spotted for me. He said it was nice to work with someone that could actually shoot. I thought that was pretty good for my first time with a scope. I have a RRA upper I swap with the long barrel for plinking. It's been a while since I've even been out shooting. Hmm...

#13 of 29 OFFLINE   TristenEugene

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Posted June 14 2009 - 12:25 AM

Thanks all of you. Thank you Robert for taking the time. I am taking all you offered and researching it. so far, you are an ACE! Thanks again.

I was in Saturn Electronics yesterday (Germany). The speaker demo area. I came home a little confused. BUT! After reading what you said about the wattage factor it is beginning to make sense. I wa trying out 6 different subs there. A JBL model that was 500 watts sounded flubby and not as tight and clean as a ElAc 2060 ESP right next to it. This ElAc sub really sounded very good. It has 2 180mm (about 7.5 in) drivers. Very unique sealed enclosure. Sucker was almost $2000 bucks though!

BTW! That JBL sub, during a somewhat intense bout of thunder (Demo DVD for surround sound) the sub driver really was going in and out intensely, the sound was distorted and,,, it just quit putting out most of it's sound. Dialing the crossover, you could hear a little, but it really seemed to quit. Do these things have some kind of overstress protection? It seems like it just failed?!

Another question here; I read where a asymmetrical enclosure can help prevent ''standing wave'' pressures. What is this.

In the end, I was listening to the sub that produced very tight lows and highs that simply did not sound like it was mechanically reproduced sound. That ElAc was as good as it was to be had in that studio.

I am going to look into SVS and the others Robert. Thanks again.

Any other info from anyone would be very much appreciated.

Oh Yeah! If I could, I would build my own Sub! Saving all that money and getting what I want. Things that go boom? Me too! Ihave my share of fun with guns and bigger guns (Cannons).

Jeff.

#14 of 29 OFFLINE   Robert_J

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Posted June 15 2009 - 05:00 AM

Quote:
Originally Posted by TristenEugene
Do these things have some kind of overstress protection? It seems like it just failed?!

Another question here; I read where a asymmetrical enclosure can help prevent ''standing wave'' pressures. What is this.
Yes, most subs have something built into them to keep the user from destroying them. There are some really determined users who can still destroy a retail sub. Some subs have nothing to protect them and rely on the knowledge and experience of the user not to push the sub past its limits. I like those subs. They usually come from companies that are more interested in value and sound reproduction.

The wavelengths involved in the sub area are much longer than a box. So the shape of the box doesn't matter. They shape of your room does though and placement is critical.

-Robert

#15 of 29 OFFLINE   TristenEugene

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Posted June 16 2009 - 01:52 AM

Well, all this is really getting me going in a particular direction. What I mean is; I have become audiophilic,, is that a correct word? , over the past several years. I found myself wanting the sound to be better and better. Where this has me today is HERE! Talking to you fine folks and absorbing all this info.

Where I am at now is looking into DIY. I went to several electronic stores to listen to various systems. I found that,, for me!,, the PR type Subs sound better. They seem to need more power to get'm up and going, but their sound is cleaner, tighter and more realistic. AGAIN! To me, for my tastes,, so far. I am continuing to look into all of it. Following RobertL's lead, I spent quite a bit of time researching SVS's subs. Very impressive numbers. That PB12 Ultra2 is way COOL! A review stated that ''...you'll send your neighbors running for their air raid shelters...'' HA! HA!

So, If anyone can steer me towards more info/help with DIY, this would be very nice.

I am after: Around 500 watt, one - two 12'' drivers with an appropriate radiator compliment.

Thanks.

Jeff.

#16 of 29 OFFLINE   TristenEugene

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Posted June 16 2009 - 02:16 AM

Right you are RobertL about user knowledge needed to keep from destroying a sub. The one I currently have has a VERY BAD rep for failing. In my case I use it like crazy for music and movies. It rocks the house. The trick,, to this one is that I never turn it up past 40% power. It seems to be way over powered for it's components. It has a BASH amp. It's made for a computer. It is a Creative S-750 7.1 connected to a Creative DDTS-100 decoder.

Some more questions: On the back of subs, what are these connections: speaker level in/out, Left and right Line level/LFE in, High and low level in. Also on speakers there are 4 connections that have to be sometimes bridged. What are these for?

Thanks again.

#17 of 29 OFFLINE   Robert_J

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Posted June 16 2009 - 04:57 AM

The speaker level connectors on subs are rarely used. 99.9% of the time you will connect the sub to the LFE output of the receiver using a coaxial cable. The speaker level connections are used with subs that do not have an LFE output.

You mentioned Germany earlier. What brands of subs do you have available to you? You may need to look at the car audio world to find a suitable DIY driver. Polk and Cerwin Vega are both known worldwide and make drivers suitable for home theater applications. If you are up for importing, then check out drivers from:
Parts Express (Dayton Reference, DVC and Titanic lines)
Audiopulse (available at Parts Express and other locations soon)
Fi Car Audio
Ascendant Audio
Sound Solutions Audio
Incriminator Audio
Acoustic Elegance (aka AE Speakers)
Elemental Designs
Exodus Audio
Creative Sound Solutions (based in Canada)
Rythmik Audio
GR Research

An amp to power them will be easy. Look no further than the German company Behringer. I use their EP-2500 amp as well as their Feedback Destroyer in my sub system.

As for the design, I'd go ported instead of a PR. Easier and cheaper as a first project. If you go with a pro amp like the Behringer then sealed is better.

-Robert

#18 of 29 OFFLINE   TristenEugene

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Posted June 17 2009 - 01:05 AM

Thanks a million! Some of the things you mentioned I have already seen and earmarked as attractive. Hmm? You really know your stuff.
Mainly here, ELAC, JBL, Klipsch and Teufel seem to reign supreme.

It seems that the amount of 'room' in the enclosure is very important for tuning. For PR types, it seems that a few grams of wt really make a ,, the difference between good sound and bad. Can you offer a good reference for getting a grip on this? A laymans reference for figuring out the proper measurements needed compared to the size of the drivers,amp and so on?

I am pretty much set on a PR type until I am convinced otherwise. I am still checking things though.

Hey! One more thing. Can I connect another subwoofer to what I have now by simply connecting a Y splitter the the sub out on my receiver? Is it that easy?

#19 of 29 OFFLINE   Robert_J

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Posted June 17 2009 - 01:23 AM

Quote:
Originally Posted by TristenEugene
It seems that the amount of 'room' in the enclosure is very important for tuning. For PR types, it seems that a few grams of wt really make a ,, the difference between good sound and bad. Can you offer a good reference for getting a grip on this? A laymans reference for figuring out the proper measurements needed compared to the size of the drivers,amp and so on?
The volume of the enclosure and the relationship between a port or a PR is critical for tuning. Ports and PR's are Hemholtz Radiators. Think of a PR as a very large port. If you need a 4" diameter, 18" long port to achieve your tuning point, then think of a 12" PR as a 12" port. A port of that size would have to be 10 feet long (not mathmatically correct, just an example). A colume of air 12" in diameter and 10' long would weigh 676g (again, just an example). That is what the mms parameter (cone weight) of the PR should be.

diysubwoofers.org will give you the background and the math. Download WinISD or Unibox (my favorite) which will help you with the calculations.

Quote:
Originally Posted by TristenEugene
I am pretty much set on a PR type until I am convinced otherwise. I am still checking things though.
Both ported and PR subs need a subsonic filter. If you go with a pro amp you will need to add that as an extra piece of electronics. Sealed subs don't need a SSF if designed properly.

Quote:
Originally Posted by TristenEugene
Hey! One more thing. Can I connect another subwoofer to what I have now by simply connecting a Y splitter the the sub out on my receiver? Is it that easy?
It is that easy. But if you go with a high quality sub, you don't want to mix it with a bargain sub. Our favorite thing to do is add 2 or more quality subs.

-Robert

#20 of 29 OFFLINE   TristenEugene

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Posted June 23 2009 - 06:14 AM

All sounds very good. Thank you very much. diysubwoofers.org is the place for me. Thank you again.

I found a cool track for testing the awe striking power of a good speaker system.
Cick on this---> Sound Effects Library Search Results
It is a sound recording of a shuttle launch. Turn it up!!!

Also I found some good bass testing tracks on youtube and Rhapsody.com The subsonic, 5-10 Hz, stuff at a moderate volume level really vibrates yur innards!


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