Need plans for a quad 18 (JBL2245H) bass reflex

Elliot Thompson wrote: DMorison wrote: The bigger the box and the lower the tuning frequency, the lower you may be able to go, but this normally comes at the cost of running out of linear excursion at lower power levels. HTH, David. That only occurs when you choose the wrong driver for the job and try to extract every bit of SPL from a single driver. Things differ tremendously, once you use the proper driver for the job .

That's why I brought it up - to try and help the OP avoid using the wrong box for their driver (or vice versa).

He seems set on using rather high powered amps for these, so over excursion is IMO almost inevitable.

Of course, I don't know how experienced he is - maybe he'll find that the extra efficiency from coupling lots of cones does indeed allow use at only a modest wattage, which will be fine - but if people don't highlight these issues before the build, then the possibility remains of the OP (or anyone else embarking on a similar project) trying to turn it up louder and being disappointed.

Elliot Thompson wrote: Building a reflex becomes more complex when you want something different than the average end user.

I don't know if I want something different than the average end user. I want to play old 70s Jamaican music and feel the bass. 90s synth bass in reggae, hip hop, house etc.

I don't want to miss out on the deepest lows. The aim is for magic in the dance.

When discussing frequencies it is interesting to note the lowest note on a bass guitar, the open E string is 41Hz. And I am also recalling that vinyl records (I won't be only playing vinyl) are said to be high passed at, IIRC, about 40Hz. If I aimed for 30Hz what compromises would I be incurring vs aiming for 40Hz. I may as well have my cake.

Just thinking aloud, a couple of people have quoted the lowest bass guitar open E string (41Hz) as a possible lowest necessary frequency to reproduce. But I am questioning if lower frequencies are still relevant. Perhaps the bass drum can have relevant info below 40Hz?

Elliot Thompson wrote:  This is where those that are familiar with reflex designs will have the knowledge to build a cabinet that meets the aesthetics and performance level one is seeking. A lot of people down play a reflex design without realising a properly design reflex requires just as much effort as building a folded horn.  It is precisely this reason why custom designs are not readily available whereas, more generic designs are available at an abundance on the Internet.  Best Regards,

Ok, so I do need to seek assistance from an experienced speaker box man.

Some previous comments about undesirable outcomes from mismatching a specific driver's characteristics with a cabinet design seem redundant if I am entering the Thiele and Small specifications of my JBL 2245H drivers into the bass reflex cabinet calculator.

Other comments regarding me having perhaps too much power for my configuration go against the recommendation of having twice the wattage per driver than the maximum RMS of the driver. Perhaps it was just warning me of the potential of blowing up drivers by turning it up too loud. I definitely don't intend to turn it up too loud. I assume that (4) quad 18 boxes with 1100W per driver playing in small to medium venues is bordering on overkill. Maybe I will be tempted to show off a little with some super Bassy tunes. But I doubt it.

I just want to be able to play Dawn Penn's 1992 version of 'No, no, no' produced by Steely and Clevie and have the synth baseline sound big, friendly and effortless.

I read the English blokes talk about which sound is the heaviest and cringe. It sounds like low self esteem egotistical male competitiveness turning what should be a fun, healing sound to dance to into a painful contest where hearing protection is required. Perhaps there is some subjectivity in what is too loud in individuals perceptions. But if you need ear plugs then that confirms to me it is too loud. I will have no part in that absurd mentality of masochism.

But hey it can be fun to push things a little and overload on bass. I may be more sensitive than most. I used to tolerate louder sound when drunk. I don't get drunk anymore.

The whole idea behind having so many drivers is to have a big effortless, friendly sound.

What do you guys think of my configuration of a quad 18 box with a double 15 on top and one JBL2445H 2 inch compression driver and multi cell wooden horn. Is that unbalanced? I assume that to get an even sound I just need to adjust the levels going to each box via the volume controls after each crossover band.

Elliott words of too much bass are soothing. Better to have too much than too little.

Can someone spoon feed me and tell me what they think are some good parameters. Just for food for thought.

I think I've communicated my sound intentions quite specifically.  

Roman wrote: Elliot Thompson wrote: Building a reflex becomes more complex when you want something different than the average end user. I don't know if I want something different than the average end user. I want to play old 70s Jamaican music and feel the bass. 90s synth bass in reggae, hip hop, house etc. I don't want to miss out on the deepest lows. The aim is for magic in the dance.

So what do you want a Quad Eighteen Box for?

Quad Eighteen boxes you see others own derived from Roots Sound systems.  None of them are going to play Hip Hop more so House Music. 

Roman wrote: When discussing frequencies it is interesting to note the lowest note on a bass guitar, the open E string is 41Hz. And I am also recalling that vinyl records (I won't be only playing vinyl) are said to be high passed at, IIRC, about 40Hz. If I aimed for 30Hz what compromises would I be incurring vs aiming for 40Hz. I may as well have my cake. Just thinking aloud, a couple of people have quoted the lowest bass guitar open E string (41Hz) as a possible lowest necessary frequency to reproduce. But I am questioning if lower frequencies are still relevant. Perhaps the bass drum can have relevant info below 40Hz?

If I recall correctly, 20 Hz - 20.000 kHz became the standard as it was based on what the human ear can hear in terms of audio reproduction. Of course, there are frequencies below 20 Hz that can be detected by the human ear. However, 20 Hz is pretty much commonly heard by the average person. Focusing on one instrument and assuming that is lowest frequency while disregarding other instruments is not how one looks to create a bass cabinet. The only person that follows that principal are those who play a bass guitar.

Have you even taken the time to enter the TS Parameters in a free loudspeaker program to determine if the loudspeakers you own are suitable for a Reflex Box?

Let me tell you how Speakerplans work. If you do not make the effort (post charts of the speaker in question in a loudspeaker simulation software) those who can help you, will not help you. The ones who know how achieve what a person seeks is willing to help along the way if we see the person is making the effort. So post some charts of the JBL 2245 in a box you designed in a loudspeaker simulation software program.

Once you do that, you will find answers and, we will help you.

Best Regards,

Here you go... http://www.linearteam.org/

Best Regards,

Elliot Thompson wrote: So what do you want a Quad Eighteen Box for?

Mostly 70s roots reggae. But also 70s and 80s soul, funk, disco, boogie dance music, hip hop, house. 

Elliot Thompson wrote: Quad Eighteen boxes you see others own derived from Roots Sound systems.  None of them are going to play Hip Hop more so House Music.

I have read people explain that bass reflex cabinets are flatter in frequency reproduction than scoops and extend lower in frequencies reproduced than scoops. Also that concert PA systems mostly use bass reflex cabinets because they are more broadly compatible with rock and other genres. How do the bass reflex cabinets used by reggae sound systems differ from other bass reflex cabinets?

Roman wrote: When discussing frequencies it is interesting to note the lowest note on a bass guitar, the open E string is 41Hz. And I am also recalling that vinyl records (I won't be only playing vinyl) are said to be high passed at, IIRC, about 40Hz. If I aimed for 30Hz what compromises would I be incurring vs aiming for 40Hz. I may as well have my cake. Just thinking aloud, a couple of people have quoted the lowest bass guitar open E string (41Hz) as a possible lowest necessary frequency to reproduce. But I am questioning if lower frequencies are still relevant. Perhaps the bass drum can have relevant info below 40Hz?

Elliot Thompson wrote: If I recall correctly, 20 Hz - 20.000 kHz became the standard as it was based on what the human ear can hear in terms of audio reproduction. Of course, there are frequencies below 20 Hz that can be detected by the human ear. However, 20 Hz is pretty much commonly heard by the average person. Focusing on one instrument and assuming that is lowest frequency while disregarding other instruments is not how one looks to create a bass cabinet. The only person that follows that principal are those who play a bass guitar.

You didn't respond to the possibility that vinyl records could be high passed at 40Hz which is interesting and I would have thought relevant when lot's of reggae sound systems that pride themselves on big bass are playing vinyl records.

If I can reproduce the full range of human hearing 20Hz to 20Khz that should be satisfactory.

I was responding to Davids advice in this thread, which was:

DMorison wrote: My advice: accept that getting down into the very low frequency range may be unrealistic, target a system that goes good and loud to about 40Hz (which is the lowest note on a normally tuned bass guitar anyway) and you'll end up with a more manageable box size.

Elliot Thompson wrote: Have you even taken the time to enter the TS Parameters in a free loudspeaker program to determine if the loudspeakers you own are suitable for a Reflex Box?

I took the time to enter into the online calculator I detailed. I will now do as you advise and use WinISD for mac and report back with useful data. This is the first time someone has required me to use WinISD or similar. 

Elliot Thompson wrote: Let me tell you how Speakerplans work. If you do not make the effort (post charts of the speaker in question in a loudspeaker simulation software) those who can help you, will not help you. The ones who know how achieve what a person seeks is willing to help along the way if we see the person is making the effort. So post some charts of the JBL 2245 in a box you designed in a loudspeaker simulation software program. Once you do that, you will find answers and, we will help you.