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Ported vs sealed Sub, What's your preference?

Zing

Retired Admin
Famous
#41
The C1’s are an upgrade from Utopias.
Nonsense. Since I didn't specify a model in the Utopia line, I'll concede that the C1s may be an upgrade over the Diablo Utopia but that's as far as I'm willing to go. The Maestro, Stella and Grande Utopias can't possibly be inferior to C1s.
 

Flint

"Do you know who I am?"
Superstar
#42
Heeman, I remembered that I have real live measurements of your room with those subwoofers tuned for a flat response (what I preferred when there).



If I recall. the subwoofer crossover is set to 40Hz (12dB / Octave), so the range from about 80Hz down is greatly influenced by the subwoofers and below about 32Hz from the steep slope we put on the 12" bass enclosures. Basically, it appears you have output at 10Hz just as loud as you have at 24Hz.
 

Flint

"Do you know who I am?"
Superstar
#46
...and just what would you recommend from there?
Probably infinite baffle subs. Also start considering those overpriced streaming players with audiophile DACs and shit. At a certain point, the better gear becomes viable.
 

Razz

Well-Known Member
#47
wait.... you have (4) PSA XS-30's and that's not enough??? Aren't those each dual drivers? You have 8 sub drivers from PSA and you want more????

That's insane!

Oh, and what are "FF MTM Ellipticals"
I did a search but couldn't find them
 

Flint

"Do you know who I am?"
Superstar
#49
wait.... you have (4) PSA XS-30's and that's not enough??? Aren't those each dual drivers? You have 8 sub drivers from PSA and you want more????

That's insane!
There's a big difference between "enough" bass and "better sounding" bass. Infinite baffle subs tend to sound better, play deeper and cleaner, and be more dynamic when done properly.
 

bmwuk

Well-Known Member
#50
wait.... you have (4) PSA XS-30's and that's not enough??? Aren't those each dual drivers? You have 8 sub drivers from PSA and you want more????

That's insane!

Oh, and what are "FF MTM Ellipticals"
I did a search but couldn't find them
@heeman you have 8 subs ? Cool
 

heeman

Well-Known Member
Famous
#53
wait.... you have (4) PSA XS-30's and that's not enough??? Aren't those each dual drivers? You have 8 sub drivers from PSA and you want more????

That's insane!

Oh, and what are "FF MTM Ellipticals"
I did a search but couldn't find them

No, I have (2) PSA XS-30's...............


and they are more than enough!
 

malsackj

Well-Known Member
#55
Ok for that sound that kicks you in the chest. It is usually not something created by the sub. It usually comes in the mids around 2 k to 5 k, or the addition of the eq and power of the upper end of the system. The typical eq used in the field has some in the lower 40 to 100 hz. and some in the 2k to 5k. So where this sits on the home speakers will determine how much you can feel this kick. This 2 to 5 k is passing the impact of the beater on the head of the drum.

kick eq.png
 

malsackj

Well-Known Member
#56
That 2 k to 5 k range is handled on my outside sound system by pyle 752 drivers. https://www.parts-express.com/pyle-pdb752-2-titanium-horn-driver-8-ohm-4-bolt--292-2550
The amp is Crown xls 1500 that is giving them 300 watts each. The horns are 60 x 40 degree patterns.

The subs are JBL 4530 scoop horns with Eminance Kappa 15 inch speakers rated for 1200 peak and I am using a Crown xls 2500 watt amp to deliver 440 watts or 700 watts when adding in the two JBL MR818 subs also rated to 1200 watt peak.
 

Flint

"Do you know who I am?"
Superstar
#57
Yes, the impression of impact includes some midrange to give it that "crack" that makes it real to our brains, the way a falling rock or punch to the face also has a treble component. But, the hit on the body only happens at lower frequencies, generally below 150Hz, for a large room or outdoor PA system.

That said, an outdoor PA or a very large room concert venue can allow a completely different experience which out homes cannot.

In an open space (or effectively open space like a concert hall or reasonable sized bar), when a speaker generates a punch waveform, like you'd get from a bass drum being whacked, which will originate from the speakers, move across the space between the speaker and the listener, wash over the listener, then move beyond the listener to never be heard again (as in an outdoor space) or reflected back 40mS or more after the initial wave, which out brains are smart enough to know are echoes. This is felt by the body as much as it is heard by the ears and leaves and impression of true "impact" which cannot be achieved in a room where most barriers are less than 20 ft apart.

In a listening room in most homes, the wave will originate from the speaker, reflect off the wall behind it, reflect off the walls to the side, reflect off the ceiling, all before reaching the listener, who be washed over by a wave which is not several mS longer than the original source signal, then before the original wave fades out, it will reflect off the rear wall, reflect again off the side walls and ceiling, and sustain for many cycles, up to 20mS before it fades out. All those reflections will have moments of being in phase and other moments of being out of phase at various frequencies and what should be a smooth impact of a bass drum washing over the body in effect become a wall of bass noise which hits the listener from all sides and in come cases just pressurized the body and ears. That is NOT going to have near the "impact" of the large space or outdoor experience.

This is why a clean signal is necessary, speakers which are quick to decelerate, a room with some bass absorption and non-parallel walls to reduce the decay time, and still it won't be the same as a concert venue. To get that experience you need a room which is at least 20 feet wide and high and deep, and still not mathematically equal or divisible.
 

Flint

"Do you know who I am?"
Superstar
#58
I decided to quickly try to draw diagrams showing what I attempted to explain above...

Here's what happens when there are two bass drum beats back to back played through an outdoor or very large room PA system:

BassImpact_Outdoors.jpg

The sound reflects off the ground (less so with a huge crowd sitting or standing on the ground absorbing bass), but is not very much delayed from the initial sound. The two waves pass over the user and he feels the pressure waves as they pass by. Then they continue onward forever. In my diagram the waves are shorter than real life, and far too close together for a double bass drum hit. But this shows what the sound does, in essence.


In a room, the same double bass drum hit can be visualized like this:
BassImpact_Indoors.jpg

This is just for two dimensions and you can quadruple the number of reflections for the double hit if you add the left and right side walls, increase the reflections by even more of you add multiple subwoofers in different locations.

In the room example the initial sound passes over the listener along the floor reflections immediately behind it. Then slightly behind that is the front wall reflection, the ceiling reflection, then the rear wall reflection followed by the tangential reflections from the floor bounce and ceiling bounce reflections, followed by the rear wall reflection reflecting back off the front wall, and so on and so on, until the energy is lost to physical movement (the drywall vibrating from the sound) or it is lost to heat (the acoustic energy converted into the micromovements in absorbing materials), or so on.

This is why it is damned near impossible to recreate the power and impact of the bass in a live concert or huge movie theater in a home environment. It isn't necessarily the size of the speakers, number of speakers, or amount of power amplification. It is more about the sense of impact being completely obfuscated by the long decay times and rumblings boomy room modes.

It is kinda like playing pink noise at you constantly compared to the impact and instant decay of a snare drum being hit. It may be the same spectral makeup, but one is extremely dynamic while the other is just a nauseating and droning noise.
 

malsackj

Well-Known Member
#59
Thanks for the great writeup and graphics. Also with the live sound the drums are not compressed as much as a recorded playback could be.
 
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