I could see how it would be true if a lot of constraints were imposed on a system. If I tried to EQ a ported 15 to play at 10hz as opposed to the same 15 sealed (bottoms out) or if I tried to get a sealed woofer to match the spl of the ported one at its vent tuning frequency (bottoms out), or if I put a 15 with specs that called for a sealed system into a vented box, I can pick them apart each and every time.
My question had to do with certain FH subs being called one note boomers. You feel thats just an EQ issue?
My question had to do with certain FH subs being called one note boomers. You feel thats just an EQ issue?
The thing that comes to mind is that in my truck it took building 5 boxes to get the TC sounds LMSr12 to sound decent. The last were were all sealed with each on dropping the system Q from .71 to .65, to .60. Each one was a dramatic change and I switched back and forth all night some boxes 3 times. I can pick any one of them out 10 out of 10 times. Its hard to believe that was an EQ issue going from a 1 cubic ft box to a 1.4 then to a 1.75....all sealed. The first 2 boxes were ported and sounded really bad. I could see the ported ones boosting the vent tuning frequency 10-12db causing that issue but the sealed boxes? Not so much.
I respect your education so I will chew on it.
I respect your education so I will chew on it.
Without generalizing, I would say 5th. A folded horn SUBWOOFER ONLY is meant to facilitate a superbly efficient transfer of bass energy to the room/space. Of course, with exceptions, they are not intended for subtlety or nuance like a sealed or transmission line enclosure is. They also must be designed bang on, otherwise you end up with what you're describing: your horn cuts off far above where you expect it to because it's either not long enough, or was improperly flared to the correct cross-section. This has little to do with EQ: you cannot EQ a horn subwoofer to perform beyond its capabilities below its cut off frequency. You can add as much as you want down there, but you're just squeezing the stone harder to get more water. That said: if you design a horn properly, it can be made to fit your application be it sound quality or simply impact and extension.
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.
Each box would have a different frequency response, and the location in the trunk and size of the car's cabin affect frequency response quite a bit.
Why is it hard for you to believe that the difference in sound was not an EQ issue?
As far as the sound quality of various types of subs, I have found the difference between sealed, ported, TH and FLH to be fairly hard to detect if they are equalized to the same response, properly phase aligned at the crossover point and run below Xmax.
That said, a "one note" version of a sealed, ported, TH or FLH enclosure can be made, and EQ won't be enough to correct the problem.
You had the red sentence backwards. I didnt think it was an EQ issue because I agree with the blue sentence
The sub's location in my hummer was exactly the same and the external size of the box wasnt all that much different. The driver was always 4" from the side in the rear in all boxes as its distance from the side was with a wooden spacer.
No I dont think EQ makes up for poor alignment choices. I think Earl's statement applies to a properly designed example of each alignment. A sealed box with a Qtc of 1.1 is never going to match the articulation of a Qtc of .57 with just EQ.
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If equalized to similar response, I would mostly agree. But then that would have to take into account phase and orientation of the port for a BR or whatever you choose. If you have several well designed systems placed throughout, it is probably very hard to detect any differences at all, because the locations of the woofers and the phase disturbances made by the room would most likely even out. But if you have few sources and they are not well designed, it would not be a big challenge to pick out any differences. That is the advantage of closed systems IMO, phase predictability.
At least I find that when taking phase into account of the design, it sounds a lot better than if aiming for frequency goals only.
EQ will not correct for improper damping or group delay. Also, the sound from a port is delayed from the initial waveform of the driver. They dont happen at the same time. 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. Lack of damping is when a feed signal stops but the speaker continues on with inappropriate sounds rather than decreasing the waveform over time. Yes adjusting EQ flattens the freq response on a graph but EQ squashes initial signal to. You're supposed to have an initial attack followed by an appropriate decay. Killing some frequency kills it during the attack too.
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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'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.
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.
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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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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.
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.
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.
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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.
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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