Having issues with PC Ultra

indus

Distinguished Member
sorry if I'm blasting this forum with silly questions. I'm having a couple of issues with my PCU

1) On really big explosions (Dark Knight, when the Batmobile explodes and when the helicopter crashes/ explodes) I get a really funny sound towards the very end of the explosion.
It sounds like a big flapping noise, I don't think its a sound that I'm meant to be hearing. Its almost as if the sub is reaching some sort of limit to its ability and then going a bit bonkers

2) Music scenes. Again TDK is a good example. When Batman goes to a nightclub:)rotfl:) to get the gangster there is dance music playing in the background. It sounds awful, really boomy.

Any suggestions?

Many thanks
 

gregmcquaid

Active Member
How have you set up the speakers/sub? What are the crossovers used and how is the gain set on the PCU.

Have the levels been calibrated to 75db with SPL meter.

Make sure that the boost on the LFE channel of the receiver is not set to high because this could cause clipping in the signal when the volume is up loud. If it is set to high then turn it back a fair bit and adjust the gain on the subwoofer to compensate.

Regards,
Greg
 

indus

Distinguished Member
How have you set up the speakers/sub? What are the crossovers used and how is the gain set on the PCU.

Have the levels been calibrated to 75db with SPL meter.

Make sure that the boost on the LFE channel of the receiver is not set to high because this could cause clipping in the signal when the volume is up loud. If it is set to high then turn it back a fair bit and adjust the gain on the subwoofer to compensate.

Regards,
Greg

Hi

Crossovers set to 80hz via the amp

SPL done yesterday

By boost on the LFE channel do you mean how manyy db its set to? Because I used the spl on that aswell

Thanks
 

KhalJimbo

Distinguished Member
What is the gain set to on the sub, ie:10 o clock, 12 o clock?
 

indus

Distinguished Member

stevefish69

Well-known Member
12 o'clock mate.

Are you sure the levels are matched with the mains. If you are running the Sub too hot, it will account for the booming and flappy sound that you are experiencing.

I used to have my PCU set at 12 noon and it turned out to be running around 15db HOT :devil:

My EQ1 recons my gain should be at around 9am, but at this moment in time i'm disagreeing how it matches the sub to the Audiolab 8000AP so i have knocked it up to 10am.
 

indus

Distinguished Member
Are you sure the levels are matched with the mains. If you are running the Sub too hot, it will account for the booming and flappy sound that you are experiencing.

I used to have my PCU set at 12 noon and it turned out to be running around 15db HOT :devil:

My EQ1 recons my gain should be at around 9am, but at this moment in time i'm disagreeing how it matches the sub to the Audiolab 8000AP so i have knocked it up to 10am.

Sorry Steve but what do you mean by 'levels matched to the mains'?

This is not a problem I get all the time, but on the big explosions (In TDK) there is this funny sound as I've mentioned. Its like something flapping/quivering and its defo coming from the sub
 

pws

Well-known Member
Hi Mate

I know TDK very well as I use it as a ref for my system.

Chapter 30 has two big bass scenes.

1. The lambo crash
2. The hospital explotion.

I also use the antimode and both these scenes overdrive the antimode with the amps sub setting set at 0Db.

To stop this overdriving I had to reduve the amp sub by -4Db.
Then i used the pressure meter to ensure the sub volume on the sub is at 78DB with the mains at 75Db.

try this as it may be that your amp is over driving the antimode.

Cheers

Paul
 
Indus,

Its port chuffing mate. I get it when playing really bassy stuff. I have mine sealed now. It's not perfect but at least you don't get that stupid noise. It is really annoying.

cheers

Graham
 

indus

Distinguished Member
Indus,

Its port chuffing mate. I get it when playing really bassy stuff. I have mine sealed now. It's not perfect but at least you don't get that stupid noise. It is really annoying.

cheers

Graham

Having read around the forum a bit more I think you might be right Graham.

I've tried it sealed, but it seems to really kill the bass. Did you find this and did you do anything to try and compensate for this?

Thanks
 

kbfern

Distinguished Member
If you have the sub output at around 12 O'clock position on the subs gain control I think that is too high, somewhere around 10-11 O'clock would be better.

Also what does your receiver show the subwoofer output channel is set at regarding LFE db level,is it a plus or minus figure.I would say that 0db should be the max setting with probably -2/-3 db being better.

You have a powerful sub there and you may also be getting some bass boost depending on the subs location in the room and also your seating/listening position.

When you say by having all the ports sealed the bass has gone,do you mean the bass has gone or that distortion is no longer there and you are getting bass but with no distortion which would be better.
 
Indus,

I have tried all three ways and have found that sealed is the only way to go as the chuffing is there on the other settings. I have my sub in the right corner of the room and have my gain on 11 o'clock with the amp on sub channel level on -2db. I listened to bassotronics and watched various heavy bass films and found up to -10 on the onkyo there was NO difference between all the 20hz, 15hz and 10hz. I find the bass much tigher on the sealed setting.

One thing that still annoys me with the sub in sealed sub is that you still hear the air being propelled up the ports which is why I don't believe this sub in sealed mode is a true sealed sub. Also in sealed mode even the really low frequencies really vibrate the house just like the other modes.

This is why I am going down the road of importing a monster USA sealed sub. I have a few options and they will all blow the Ultra away in every department. There's a few custom options too I am looking into.

cheers

Graham
 

indus

Distinguished Member
Hi

The amp output for the sub (at the time) was about -3.5db

KBfern what I mean is this. Referring to the scene in TDK when Joker gatecrashes Bruces cocktail party. Batman punches the Joker in the chest, with all ports blocked this just sounds like a punch, very little sonic impact.

With some of the ports unblocked this sounds like a big thud with bass that is heard and felt. I'm sure thats not distortion I'm hearing, its a lovely bassy thud

So sealing helped tame alot of the weird noises I was hearing at the very climax of an explosion (flapping, quivering, air moving) but I lost out on other effects

Thanks
 
Indus,

That is defo port chuffing. The only way you will stop that is to go sealed mate. I've been looking at some ported subs aswell as the sealed subs in america but the sealed subs have much larger ports. One I am looking at is a 18" Elemental design sub with a 6" port. The box is 37" high by 30" deep by 25" wide. A real monster and weighs 215lb.

I really can't put up with the port chuffing and still stand by what I say with regards to the metal lid being a design issue and needs to be cloth or designed in a way that you don't have a lid and just have a flat surface with the ports neatly at the top.

Funky waves in america do a similar sub to this but larger and he has designed it so it is flat at the top with the ports on their own. Mind you that has a 15" driver and stands over 57" tall by 21" wide and has a 1300 watt amp. I have spoken to Nathan at funky waves and he went into great detail with me regarding the chuffing. He makes custom subs. A really nice guy. Blew me away with his knowledge.

cheers

Graham
 

Prize78

Well-known Member
Hi

The amp output for the sub (at the time) was about -3.5db

KBfern what I mean is this. Referring to the scene in TDK when Joker gatecrashes Bruces cocktail party. Batman punches the Joker in the chest, with all ports blocked this just sounds like a punch, very little sonic impact.

With some of the ports unblocked this sounds like a big thud with bass that is heard and felt. I'm sure thats not distortion I'm hearing, its a lovely bassy thud

So sealing helped tame alot of the weird noises I was hearing at the very climax of an explosion (flapping, quivering, air moving) but I lost out on other effects

Thanks

I've been following this thread with interest, and today i was watching TDK, especially the scenes in question. I have a sealed Epos Els sub...Ok, not the most expensive thing on the market, but I believe, a very good subwoofer. The punch in the chest scene gives a VERY deep powerful thud....followed by several other good thuds in the ensuing fight scene. Another scene to "test" is the part nearer the start where the woman gets into her car.....undoes the envelope and it says "UP" in it.....followed by some lovely bass action.
My point is, that although my sub is considerably cheaper than a PC Ultra, it is a sealed sub, but offers great "thuds" on the scenes mentioned.
Not sure how this helps, but i thought i'd offer my two pennies worth.
Another good scene for "sudden bass" is around 54:30 where they're testing the gun.
 

indus

Distinguished Member
I've been following this thread with interest, and today i was watching TDK, especially the scenes in question. I have a sealed Epos Els sub...Ok, not the most expensive thing on the market, but I believe, a very good subwoofer. The punch in the chest scene gives a VERY deep powerful thud....followed by several other good thuds in the ensuing fight scene. Another scene to "test" is the part nearer the start where the woman gets into her car.....undoes the envelope and it says "UP" in it.....followed by some lovely bass action.
My point is, that although my sub is considerably cheaper than a PC Ultra, it is a sealed sub, but offers great "thuds" on the scenes mentioned.
Not sure how this helps, but i thought i'd offer my two pennies worth.
Another good scene for "sudden bass" is around 54:30 where they're testing the gun.

Its useful that you are using the same film and scenes as me.

The scene when the judge gets blown up in the car, is bonkers without the bungs. All sorts of sounds, like a a quiver board and lots of air being moved.

With three ports blocked, it sounds very controlled ie none of those funny noises. But then I get the problem with the Batman punches that lose their impact.

Anyway, plenty more playing to do yet:thumbsup:
 

Stuart

Distinguished Member
What sort of volume are you listening at when you get the chuffing?

PS. I may have to watch DK tonight again, purely for research purposes :devil:
 

Member 639844

Former Advertiser
Indus,

That is defo port chuffing. The only way you will stop that is to go sealed mate. I've been looking at some ported subs aswell as the sealed subs in america but the sealed subs have much larger ports. One I am looking at is a 18" Elemental design sub with a 6" port. The box is 37" high by 30" deep by 25" wide. A real monster and weighs 215lb.

I really can't put up with the port chuffing and still stand by what I say with regards to the metal lid being a design issue and needs to be cloth or designed in a way that you don't have a lid and just have a flat surface with the ports neatly at the top.

Funky waves in america do a similar sub to this but larger and he has designed it so it is flat at the top with the ports on their own. Mind you that has a 15" driver and stands over 57" tall by 21" wide and has a 1300 watt amp. I have spoken to Nathan at funky waves and he went into great detail with me regarding the chuffing. He makes custom subs. A really nice guy. Blew me away with his knowledge.

cheers

Graham
Hi graham,

You may be interested to know I managed to get my sub chuffing last night. It was on the pulse scene Markymarky brought with him, e came to demo the ultra. The thing is we really has to push the sub to force it to do it. I run about 4db hot of what Audyssey sets the sub at so its like 78/79db compared to when the speakers are at 75.

We put the scene on and the sub was fine. We upped the amp volume to zero (reference level) and it was still fine. FYI Ive measure my Ultra in my room and it hits 104db at 10hz at this volume level. I started to up the gain on the sub channel then, its normally at -5 in the amp menu at my usual setting. The Ultra didnt start chuffing till we were at +5 on the sub channel. So thats a good 15db higher than Audyssey sets the sub and playing at the reference level.

I never watch movies that loud, its just too loud, and I could certainly never up the sub channel like that either. I now know what chuffing sounds like though which is a plus, I know what I'm listening for, but I also managed to prove I'm never going to hear it on anything using my normal settings, even upto reference volumes :smashin:

Its strange though how the 2 Ultra models differ so much, I'll certainly keep them in mind. I knnow I certainly couldnt live with the chuffing sound, its awful.
 
Moonfly,

Excellent news in a weird sort of way. I still have mine sealed as mine does chuff at -10db. I spoke to Nathan at Funky waves and he has suggested the 15.3 which is the cubed sealed sub. It's 24" cubed (bloody massive) with a 1300 watt amp and an upgraded 15" driver with two 18" passive radiators. He's quoted me about $2500 canadian dollars including shipping. He said that this would ABSOLUTELY BLOW the Ultra out of the water.

I am still toyed with the Seaton Submersive aswell along with the ED A7-450 sub. I made a paper dummy of the front the ED sub and boy it is MASSIVE. I have noticed that the exchange rate is getting better so I may wait a month.

I really can't wait until I get one. I still think the Ultra isn't that good with music. I've tried various types of music including guitar music and it just doesn't have the attack I want. Don't get me wrong it's good with movies but I personally think it is overrated some what.

cheers

Graham
 
AV junkie,

The chuffing does go but you are still left hearing the air coming up and out of the ports. Plus it looks really ugly.

This is what I meant by maybe a re design of the top with no lid but have it flush smooth on top with 3 ports. It would look much better and sound better.

Have a look at the 15.1 sub on Funky Waves. You'll see what I mean.

cheers

Graham
 

Stuart

Distinguished Member
So is it the flexing of the grill causing the chuffing? If so, perhaps reinforcing it may help, say with a couple of small bars across the width of it.

Apologies if I've misunderstood.
 

Member 639844

Former Advertiser
Moonfly,


I really can't wait until I get one. I still think the Ultra isn't that good with music. I've tried various types of music including guitar music and it just doesn't have the attack I want. Don't get me wrong it's good with movies but I personally think it is overrated some what.

cheers

Graham
I understand where your coming from, there are times when I feel its very deep but missing a little something further up. Ive always loved REL subs and consider them some of the best musically. Mark even noted how with some tracks the punch and attack of the SVS wasnt as 'there' as the REL B1 he has. They are a formidable HT sub, but Ive no doubt there are many better for music, even the Monolith is probably a little better.

I went for the Ultra because I plan to get some good speakers and want to let them do most of the music work. I dont want to much boom due to the speakers and sub boosting each other because i like very pure bass. While this suits me (hopefully) Ive no doubt its not the way forward for everyone, or even most people.
 

Member 639844

Former Advertiser
So is it the flexing of the grill causing the chuffing? If so, perhaps reinforcing it may help, say with a couple of small bars across the width of it.

Apologies if I've misunderstood.
I think their are two kinds of chuffing that happen. One is the ports themselves doing it as the air is forced through, and ends up puffing out more like a steam train than the smooth flow its supposed to have. The other is simply air being forced through the tiny holes in the grill, they start to make a slight noise due to air rushing through them.

It is possible to get either of these, or both together at the same time.
 
Moonfly,

I must admit I do even have a little concern even the new SVS sealed subs as from what I vaguely remember they are not a big box. I know they will house a 16" driver but will that have passive radiators too as the conversation with Nathan was that to get the low stuff passive radiators are a big must.

My problem is I can't rely on my RS6's for stereo alone although they do sound good, I love bassy music.

I will let you know in due course what ever sub I get sounds like. If SVS won't take the sub back them I will have to sell it so I will let you all know in a short time.

cheers

Graham
 

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