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Old 4th September 2013, 04:59 PM   #11
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Originally Posted by SpinMonster View Post
Ringing (resonance lack of damping) is not just an issue of amplitude where cutting a freq fixes the problem, its in the time domain too as on a waterfall plot.
I'd expect the Hummer cabin has panels that ring for far longer than a sealed box with a QTC of 1.1.
When it comes to resonance, a little can go a long way .
Did you measure the various cabinets response both outdoors and in the vehicle to determine which contributes more ringing?
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Old 4th September 2013, 06:01 PM   #12
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Originally Posted by weltersys View Post
I'd expect the Hummer cabin has panels that ring for far longer than a sealed box with a QTC of 1.1.
When it comes to resonance, a little can go a long way .
Did you measure the various cabinets response both outdoors and in the vehicle to determine which contributes more ringing?
I never built a sealed sub with greater than a .7 qtc. I was simply making a point to illustrate that a Qtc of 1.1 and a Qtc of .57 cant be EQ'd to sound the same because ringing isnt just frequency, its also a time issue. No one would dare say a ribbon tweeter EQ'd to flat is going to sound the same as a Scan Speak 6600 EQ'd to flat.

I had a dozen or so subs in the same truck and they all sounded great. If my truck's panels didnt interfere with any of the other subs, why did it with this one? 4 boxes later it was livable because I changed the Qtc therefore Qtc is a SQ issue. I'd credit the theory if no sub ever sounded good in the same truck but seeing as the TC was the only one that bad, its not the truck.

It cracks me up. Guys go ape crap over a tiny distortion blip on a tweeter test but when it comes to subs, eq fixes all and they all sound the same.

I guess we need a waterfall plot with a big time axis to show that even EQ'd to flat, ringing is still there after the signal to the sub stops or that a port sound's time arrival doesn't coincide with the woofer's.
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Old 4th September 2013, 06:22 PM   #13
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Originally Posted by gedlee View Post
Putting all the subjective perceptions aside. as far as I can tell from all my investigation into LF sound in rooms, the source type just washes out when you use multi-subs and EQ. The excursion capability and power handling of the driver is all that matters in that part of the equation. The box type has very little impact on either of those parameters. At some frequencies a resonant system, like ported, TL and/or horn may have some excursion enhancement, but at other frequencies it might be degraded. The simple closed box is very hard to beat when one has good drivers (excursion and power handling), enough amp volts and DSP capability. Everything else is just bigger for the same resulting SPL in the room.

The difference in subjective listening and your test results simply shows you arent testing the variables that affect the subjective sound. Zaph states ribbon tweeter's detail is from distortion but the waterfall plots are amazingly clean. Thats because there is nearly no weight to a ribbon's drive surface allowing it to start and stop on a dime, hence detail. All tweeters that exhibit super detail have such waterfall plots. I fail to see why a sub wouldnt have this variable as a factor in detail.

The peak in freq response of a high Qtc sealed sub is not the only consequence of ringing. In the time domain, those freq keep sounding off longer than a low Qtc system after you stop the signal being fed to the sub.

How do you measure time arrivals for ringing in your tests? When you stop the signal to a sub and it rings, it still makes sounds when its supposed to be silent. Not all subs stop making sound when they are supposed to. Ports make sound that is delayed. These are not freq response errors, they are time errors and getting a flat or averaged in room response while you are feeding a signal is not measuring the sound a speaker makes after you stop that signal.

Yes the room is a major factor as a bad room will ruin the sound of a good sub. A great room though isnt going to turn a garbage sounding sub into a reference level sub. To have great sound you need a great room set up with a couple of great subs.

Last edited by SpinMonster; 4th September 2013 at 06:26 PM.
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Old 4th September 2013, 06:48 PM   #14
OMNIFEX is offline OMNIFEX  Jamaica
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Quote:
Originally Posted by SpinMonster View Post
Where in order would a folded horn's sound quality fall?

1-sealed
2-transmission line
3-ported
4-passive radiator

I've never heard one.
A Folded Horn would fall under sealed cabinet with a boost in frequencies above 60 Hz.

Think of it as building a woofer in a small sealed box. It offers a lot of impact/punch above 55 Hz but not much below 55 Hz without relying heavily on equalisation. Now amplify that signal around +5dB to +10dB and that is a folded horn.

Folded horns also have a tendency of sounding as someone banging a hammer against a piece of wood. Whether that is a good thing or bad thing all depends on your musical preference.

That is a general idea what a folded horn sounds like.

If you have a sealed box just place it in a corner with the front of the driver facing the wall to hear what a folded horn sounds like.
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Last edited by OMNIFEX; 4th September 2013 at 06:51 PM.
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Old 4th September 2013, 06:54 PM   #15
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Originally Posted by SpinMonster View Post
I had a dozen or so subs in the same truck and they all sounded great. If my truck's panels didnt interfere with any of the other subs, why did it with this one?
Couldn't tell you without a frequency and impulse response of the dozen previous subs and the various TC sub cabinets which presumably go lower, and therefore would exhibit (subjectively and objectively) more delay and cabin ring.

I am of the opinion that transient qualities of subs are audible, but having heard very "tight" sounding FLH, TH, and BR outdoors, I usually find that the room and time/phase integration in the crossover region are the main culprits to a perceived degradation in low frequency transient qualities.
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Old 4th September 2013, 09:38 PM   #16
wg_ski is offline wg_ski  United States
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Originally Posted by OMNIFEX View Post
Folded horns also have a tendency of sounding as someone banging a hammer against a piece of wood. Whether that is a good thing or bad thing all depends on your musical preference.
Unequalized and undersized, front loaded horns have a "bonnnnk bonnnnk" sound to them, caused by a big haystack peak between 100 and 130 Hz. Unfortunately, you see a lot of them used that way because they're still extremely loud relatively speaking. First time I heard a single lab horn I swore there was a loose panel rattling around inside it. The unequalized response peak was that obnoxious. Get a critical mass of these things and the 'wonkiness' goes away - they self-equalize and you get good low end extension to the capabilities of the horn. High Q sealed boxes won't do that - if you've got a boomy, tubby box you're stuck with it no matter how many you have or how you spread them around the room.
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Old 5th September 2013, 02:34 AM   #17
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Originally Posted by weltersys View Post
Couldn't tell you without a frequency and impulse response of the dozen previous subs and the various TC sub cabinets which presumably go lower, and therefore would exhibit (subjectively and objectively) more delay and cabin ring.

I am of the opinion that transient qualities of subs are audible, but having heard very "tight" sounding FLH, TH, and BR outdoors, I usually find that the room and time/phase integration in the crossover region are the main culprits to a perceived degradation in low frequency transient qualities.
All are max flat outside the truck. A TC LMSr 12 extends to 47 hz on its own max flat. They dont go lower. A sealed Alpine SWR1522 hits 37hz max flat and sounds subjectively cleaner in a .7 Qtc box and I can pick it out every time. A ported Scan Speak L26Roy tuned to 30hz is flat to 31hz. All of these subs have more output from 30 to 47hz than the TC before EQ. They all sound better. The TC playing deeper is because it handles insane amounts of power allowing for tons of EQ.

Regardless of the arguments about motor strength and cone weight, the 330grm weight TC 12" cone is not doing the same start and stop performance of the 106grm 10" L26Roy.

Having heard various alignments sounding tight and deep isnt the point. The fact that you hear differences using the same driver in various alignments is.

Last edited by SpinMonster; 5th September 2013 at 02:41 AM.
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Old 5th September 2013, 01:44 PM   #18
OMNIFEX is offline OMNIFEX  Jamaica
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Quote:
Originally Posted by wg_ski View Post
Unequalized and undersized, front loaded horns have a "bonnnnk bonnnnk" sound to them, caused by a big haystack peak between 100 and 130 Hz. Unfortunately, you see a lot of them used that way because they're still extremely loud relatively speaking. First time I heard a single lab horn I swore there was a loose panel rattling around inside it. The unequalized response peak was that obnoxious. Get a critical mass of these things and the 'wonkiness' goes away - they self-equalize and you get good low end extension to the capabilities of the horn. High Q sealed boxes won't do that - if you've got a boomy, tubby box you're stuck with it no matter how many you have or how you spread them around the room.

Your experience sounds like mine

I've searched many times trying to find the loose panel (which was never there) that made that sound. I eventually gave four 18 inch folded horns away to someone just starting out in the business. At least the Lab Horn is large enough to go low when using multiples. 7 foot or under folded horns will bore your ear with tons of upper harmonics with no fundamentals to dampen the offending notes. But there are many who are fond of that type of sound for one reason or another.
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Old 5th September 2013, 02:33 PM   #19
zobsky is offline zobsky  India
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Quote:
Originally Posted by SpinMonster View Post
Where in order would a folded horn's sound quality fall?

1-sealed
2-transmission line
3-ported
4-passive radiator

I've never heard one.

Seems that one can't get a straight answer anymore , these days.

IMO, well designed, a horn sub sounds superior to all of the above. It might not go as low, though (unless it's fairly large)
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Old 5th September 2013, 02:58 PM   #20
gedlee is offline gedlee  United States
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Originally Posted by SpinMonster View Post
I never built a sealed sub with greater than a .7 qtc. I was simply making a point to illustrate that a Qtc of 1.1 and a Qtc of .57 cant be EQ'd to sound the same because ringing isnt just frequency, its also a time issue.


So you don't buy the time/frequency equivalency?
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