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Discussion Starter #1
Edit: Cut from another thread that went off topic.

Mike P.


Ryan,

I think alot of people get too hung up on simulations in WinISD to be honest. My subs for example tuned to 13.5hz, people where saying the 1st port resonance is too low at 138hz and you won't be able to use a higher crossover than 80hz and the 2" port is too small, your get chuffing. All I can say is rubbish!

I played a 10hz test tone at -10db yesterday, I played a 15hz test tone at -10db yesterday and I also played a 20hz test tone at -10db yesterday and NO hint of port noise and I still get tonnes of upper bass output and even more lower bass output. The subs have worked out better than my higher QTC dual sealed sub which you would think would have alot more upper bass but didn't in my opinion.

And I agree with you mate why do people go on about films with low bass output and saying can you watch such a such film say like the hulk, black hawk down, Transformers 2 etc... at reference if they are only going to build a 20hz ported sub. That to me is pointless!

I personally find any higher volume than -20db with my two subs I start getting paranoid its too loud for the neighbour. All the low bass films mentioned woudn't sound the same in my opinion with a sub or subs that can't output those low frequencies.

The maelstroms are perfect for using in low frequency ported subs. Two of those tuned to 10hz with 2000 watts would sound crazy for films like the hulk etc...

I wish I could have stretched the extra cash because I would now be sitting with two of those with two EP4000's amps in my living room. That would be very interesting! :hsd:

cheers

Graham
 

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Elite Shackster
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Re: Would it be a wise to tune low, but have your hpf high

I have to say Graham, I dont think I know of anyone else who craves bass as you do :D. I would still like to compare one of your subs to mine eventually, it sure would be an interesting comparison.
 

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Discussion Starter #3
Re: Would it be a wise to tune low, but have your hpf high

Dan,

Yes that would be very interesting especially as I have not had to boost my bottom end at all and has a natural 4db lift between 10 and 16hz.

cheers

Graham
 

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Re: Would it be a wise to tune low, but have your hpf high

gperkins said:
I think alot of people get too hung up on simulations in WinISD to be honest. My subs for example tuned to 13.5hz, people where saying the 1st port resonance is too low at 138hz and you won't be able to use a higher crossover than 80hz and the 2" port is too small, your get chuffing. All I can say is rubbish!
With all due respect, all I can say is some people can hear things better than others. Those tradeoffs may have worked out ok in the end for you, but other people might easily be able to pick up on the chuffing and resonances which are there.

The advice given on this forum for DIY subs tries to lead people to top notch performance. Some may not require that, but, to not warn about the consequences and try to steer away from them would be irresponsible.
 

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Elite Shackster
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Re: Would it be a wise to tune low, but have your hpf high

Dan,

Yes that would be very interesting especially as I have not had to boost my bottom end at all and has a natural 4db lift between 10 and 16hz.

cheers

Graham
All sealed subs require the low end boosting. In the commercial world they achieve this by augmenting signal as it travels through the amp, so you never know about it. The thing with sealed subs is they need to be super capable so as to be able to boost the low end without introducing limitations. All the commercial sealed subs that do this well are very expensive, which is why porting is popular I guess, its a natural cost effective way of achieving this.
 

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Discussion Starter #6
Re: Would it be a wise to tune low, but have your hpf high

Steve,

With due respect too, I know chuffing, I had plenty of that with the SVS PC13 ultra. If there was a badly designed ported commercial sub then that would at the top of my list. I could make that chuff really easy in my room. Even the SVS tech expert sales guy heard it in my room when he came over to take it away.

With regards to 1st port resonance I certainly am no expert but if this is audible then I don't hear it and never have and I still stand by what I said with regards to watching and experiencing films with low frequencies. Trades off's, yeh there's always trade off's and I bet if you stick one 18" driver in and identical ported box with another they will always sound different. I don't think I am purely lucky. I think the drivers parameters help in my application. I have experienced pretty much all the SVS subs which also includes the Sunfire HRS12 and there has only been one out of them which even came close to my expectations and that is the PB13 ultra.

My sunfire HRS12 was tuned to about 20hz I reckon and that doesn't come close to even one of my ported subs. I think I still have the best of both worlds with movies and music even though they are tuned low and I like to think I am a good judge of what sounds good with the subs I have owned.

Its always down to what people prefer and if they want to build a higher tuned sub then so be it but don't expect to get the same performance when it comes to watching films with low low bass like the ones everyone mentions.

Its only my opinion at the end of the day.

cheers

Graham
 

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Re: Would it be a wise to tune low, but have your hpf high

Hey, I'm definitely not disputing the benefits of a low tune - I'd be one of the last guys to do that, it's the basis of my LLT concept. All I was saying is that things like first port resonance and port chuffing are real, audible side effects that we should design around minimizing or eliminating. I don't recall your particular sub design, but a 2" diameter port and 138hz first resonance sound awfully dangerous to me in terms of audible negative side effects. At the end of the day, if it works for you, that's probably all that matters to you, but it still won't change the sound advice given for other designs.
 

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Discussion Starter #8
Re: Would it be a wise to tune low, but have your hpf high

Steve,

I respect what you are saying mate. You are way way more knowledgable than me. All I can go on is past experience with the subs I have made and owned. MikeP said my 1st port resonance would be fine with a 80hz crossover which is what I am using. Perhaps you could let me know what a port resonance would sound like as having not experienced it myself. My subs come out at 311 litres each and I wouldn't class them as LLT subs by any means but they are very clean sounding subs.

I think the best test would be for someone who has great expertise to actually be in my living room to give a professional opinion. At the end of the day we will all say our subs sound the best because why wouldn't we but having made a sealed sub and a ported and plotted seperate graphs for both I can personally say the ported ones I have produced have given a much better result.

As I said before the FI Q18 drivers parameters mean you have to make big boxes to get the best out of them unlike maelstroms which are the opposite which is why my 11 cu ft dual sealed sub came out with a high qtc which would give much better upper bass and less towards lower bass. I still got flat to 12hz with my sealed sub but it never had the authority like my ported subs have. You only have to look at my graphs to see why. Apart from a dip at 33hz everything else was pretty good with lots of output at all other frequencies. I could get even better results if I had the space but unfortunately I don't. If only I did then another build would be coming up.

cheers
Graham
 

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Discussion Starter #10
Re: Would it be a wise to tune low, but have your hpf high

I should say that the 311 litres was internal size.

cheers
Graham
 

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Re: Would it be a wise to tune low, but have your hpf high

I should say that the 311 litres was internal size.

cheers
Graham
I personally would firmly class these as LLT Graham. IIRC, the official criteria require at least a 15hz tune which yours meet, they are certainly large, and if they dont meet the performance criteria I'l eat my own hat :D
 

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Discussion Starter #12
Re: Would it be a wise to tune low, but have your hpf high

Dan

I appreciate that. I have to say I never thought of them as LLT subs just ported subs but I have never got around to reading Steve's low down on LLT. I will this week.

I guessed that most people would do sonotube subs as LLT.


cheers

Graham
 

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Elite Shackster
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Re: Would it be a wise to tune low, but have your hpf high

The exact shape of a sub is more preference than anything. An LLT just seems a variation on an EBS design to me though, with a bit of tweaking to probably improve SQ.
 

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Re: Would it be a wise to tune low, but have your hpf high

Hey, I'm definitely not disputing the benefits of a low tune - I'd be one of the last guys to do that, it's the basis of my LLT concept. All I was saying is that things like first port resonance and port chuffing are real, audible side effects that we should design around minimizing or eliminating. I don't recall your particular sub design, but a 2" diameter port and 138hz first resonance sound awfully dangerous to me in terms of audible negative side effects. At the end of the day, if it works for you, that's probably all that matters to you, but it still won't change the sound advice given for other designs.
Port Resonance is rarely a major issue. Think about how many ported speakers exists with resonance. Perceptual research I'm sure would show this to not be problematic.

Now port chuffing and compression are certainly real issues that should be avoided.

I think the OP has enough information to move forward.
 

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Re: Would it be a wise to tune low, but have your hpf high

Passive radiators are really just more expensive way of achieving what a port does, while at the same time avoiding the possible resonance and chuffing issues. In theory, you could still build an LLT design using pr's. How expensive that might become will take a little working out, and only you can decide if its worth it for you. Theres nothing inherently wrong with either a pr or ported design as long as you design it right.
 

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Re: Would it be a wise to tune low, but have your hpf high

gperkins said:
Perhaps you could let me know what a port resonance would sound like as having not experienced it myself
It is a one note tone, similar to a brief duration of a sine wave. If you want to hear what it sounds like at a higher magnitude than what it is being produced at in your system currently, increase your crossover to 150hz or 200hz and listen to some music. It should stand out fairly obviously then, as it will be at full magnitude. If you notice the sound (and you should be able to, as I can percieve my 234hz resonance with a 200hz crossover), then you may find you can still percieve it when you switch back to an 80hz crossover, just at a reduced level.

In fact, you may want to avoid that test altogether because it may end up driving you crazy if you know what to listen for :R

Moonfly said:
Did you come up with the LLT philosophy?
Yes. People have obviously designed and built large and low tuned ported subwoofers before me, and the EBS concept has been out for a long time, but I haven't seen anyone approach a design with the intent of maximum overall performance via porting while minimizing negative port side effects through the use of an infrasonic (and thus inaudible) tune and proper porting that meets certain criteria. The EBS design concept is vague at best and can be a total disaster in terms of performance at worst. If one follows the design characteristics of my LLT Explained, they are essentially guaranteed excellent performance and accuracy, limited primarily by the driver of choice. In other designs, the alignment itself tends to be a limiting factor.

That said, a lot of people think they have LLTs when they actually don't. You can't just make a big ported sub and have it be a LLT - that ambiguity is reserved for EBS :sarcastic: I have actual design characteristics spelled out in my Explained post that have to be met. A 2" diameter port and 138hz first resonance, for example, would disqualify a design from being a LLT, so this:
I personally would firmly class these as LLT Graham
is incorrect.

Passive radiators are really just more expensive way of achieving what a port does, while at the same time avoiding the possible resonance and chuffing issues.
Ehh. A PR has a 6th order rolloff as opposed to a port's 4th order, meaning output will die off faster below tune with PRs. Also, a PR's suspension is rarely as linear as an air spring, so the output around tune will typically have a little higher THD.
 

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Re: Would it be a wise to tune low, but have your hpf high

is incorrect.
We've been down this road before :). I'm in no way undermining the specific LLT criteria you have set out (and I didnt realise it was actually your baby :T) , I only meant that personally I would consider Grahams subs Large Low Tuned subs. Like I have said before, large is a little smaller for just about all of us in the UK, not withstanding our freind Graham of course :devil:. I also understand where your coming from with the EBS design, and the one I had, while a very good performer, did have short comings I eventually decided I had to move on from, so I can understand a desire to fix criteria that would improve on the EBS design.

I may one day have to build myself an LLT to your spec to see how it compares to my current favoured design.

Ehh. A PR has a 6th order rolloff as opposed to a port's 4th order, meaning output will die off faster below tune with PRs. Also, a PR's suspension is rarely as linear as an air spring, so the output around tune will typically have a little higher THD.
Once you go into the specifics then your spot on, but as I said, a pr is basically a way to achieve a lower tune, just as a port does and there is nothing incorrect about that statement. I dont think the OP has yet looked into the exact specifics of ports vs pr's, or why he might want to choose between them. A quicker roll off isnt particularly a bad thing assuming the tune is low enough, and a little extra THD, if inaudible or very hard to detect, might be preferable to a risk of chuffing or port resonances. Depending on the amount of space the OP has to work with, a pr may well be preferable, especially as the final built sub will likely be smaller than a ported design.

I think it could be time for the OP to chip in here.
 

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Re: Would it be a wise to tune low, but have your hpf high

My big mistake was not taking into account that the IXL couldn't get to reference the way I built it without a whole lot of room gain. I counted on room gain too much, in other words. When it became obvious I had very little of that, I was then faced with two choices... three more IXL 11Hz builds; give away the current IXL box, re-build it at a 15Hz tune, build a second one (and require a second amp); or do what I ultimately decided on doing... give up on the subsonic content I can't afford to bring to a reasonable level in here anyway and build a 16Hz tapped horn :D

Given that the Reckhorn's 10Hz highpass is more like a 12Hz anyway, the tapped horn is probably among the cheaper things I could have done with this room, though I may have been ok with a second 11Hz IXL too. I reckon I'll be more than happy enough with the TH though, and a second one of them is not out of the question (got room to stack two of them behind the projection screen - muahahaha!).
oh sweetness!

Ryan,

I think alot of people get too hung up on simulations in WinISD to be honest. My subs for example tuned to 13.5hz, people where saying the 1st port resonance is too low at 138hz and you won't be able to use a higher crossover than 80hz and the 2" port is too small, your get chuffing. All I can say is rubbish!

I played a 10hz test tone at -10db yesterday, I played a 15hz test tone at -10db yesterday and I also played a 20hz test tone at -10db yesterday and NO hint of port noise and I still get tonnes of upper bass output and even more lower bass output. The subs have worked out better than my higher QTC dual sealed sub which you would think would have alot more upper bass but didn't in my opinion.

And I agree with you mate why do people go on about films with low bass output and saying can you watch such a such film say like the hulk, black hawk down, Transformers 2 etc... at reference if they are only going to build a 20hz ported sub. That to me is pointless!

I personally find any higher volume than -20db with my two subs I start getting paranoid its too loud for the neighbour. All the low bass films mentioned woudn't sound the same in my opinion with a sub or subs that can't output those low frequencies.

The maelstroms are perfect for using in low frequency ported subs. Two of those tuned to 10hz with 2000 watts would sound crazy for films like the hulk etc...

I wish I could have stretched the extra cash because I would now be sitting with two of those with two EP4000's amps in my living room. That would be very interesting! :hsd:

cheers

Graham
it's crazy going from the black sheep odd ball out to having someone else think the same things as me. I could have typed that post myself. BTW..guess who got a big fat check today? guess who's ordering a whole bunch of Fi subs?

With all due respect, all I can say is some people can hear things better than others. Those tradeoffs may have worked out ok in the end for you, but other people might easily be able to pick up on the chuffing and resonances which are there.

The advice given on this forum for DIY subs tries to lead people to top notch performance. Some may not require that, but, to not warn about the consequences and try to steer away from them would be irresponsible.
gulp. i too am well aware of this. sigh.
 

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Re: Would it be a wise to tune low, but have your hpf high

I have to say Graham, I dont think I know of anyone else who craves bass as you do :D. I would still like to compare one of your subs to mine eventually, it sure would be an interesting comparison.
eh-hem... excuse me Dan?

:D

Please close thread
my last post in this thread:

Graham's port is a 2" x 21.5" slot port or something close to that... not a 2" round port!

I'm done here. dueces!
 

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Discussion Starter #20
My port is 20.5 by 2 by 49 inches long so youre pretty cloe. I nearly a while back bought a sub from nathan at funky waves and that had PRs.

Ryan I am looking foward to seeing how you get on.

Ive never heard a sub with PRs so I guess it would be good to hear one to compare.

You cant really tell how passionate we are about HT can you. Whatever you decide to do I wish you the best of luck.

cheers graham
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