Speakerplans.com Homepage
Forum Home Forum Home > Plans > Ported Enclosures
  New Posts New Posts RSS Feed - Need plans for a quad 18 (JBL2245H) bass reflex
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Need plans for a quad 18 (JBL2245H) bass reflex

 Post Reply Post Reply Page  123>
Author
Message
Roman View Drop Down
Registered User
Registered User


Joined: 01 April 2017
Location: New Zealand
Status: Offline
Points: 58
Post Options Post Options   Thanks (0) Thanks(0)   Quote Roman Quote  Post ReplyReply Direct Link To This Post Topic: Need plans for a quad 18 (JBL2245H) bass reflex
    Posted: 09 February 2018 at 1:40am
Here is my initial post with lots of info. But got no responses regarding plans.
https://forum.speakerplans.com/topic99270.html
I am using JBL2245H 600W 8 Ohm speakers.
I want to build 2 quad boxes. Just like Paul Axis valvatron quad wardrobe and Dub Specialist House of Joy build.
What do I need to know? 
From my googling. My current assumptions are:
I need to consult the JBL data sheet of the 2245H and use the information to build a compatible cabinet in terms of design type, volume, tuning. ???
If Paul Axis or Dub Specialist gave me plans for a quad bass reflex cabinet would it be incompatible with the 2245H driver?
I may need to use speaker design software.
Can someone give me the ABC's of what I should do to get this right.
Maybe make an MDF prototype before committing to 18mm birch.
I also want to make a matching double 15 the same width as the quad box that will hold 2 JBL 2226H 600W, 8 Ohm speakers.
I will have 2 Markus Klug 10 cell MK1005B wooden horns on each double 15 box. So a would have 2 identical configurations of a quad, double 15 and 2 horns. 2 quads, 2 double 15s and 4 horns total.
Retro look with recessed grills.

What would be the best amps for my setup? 

Back to Top
Roman View Drop Down
Registered User
Registered User


Joined: 01 April 2017
Location: New Zealand
Status: Offline
Points: 58
Post Options Post Options   Thanks (0) Thanks(0)   Quote Roman Quote  Post ReplyReply Direct Link To This Post Posted: 09 February 2018 at 1:46am
Here is the JBL data sheet:
http://www.jblpro.com/pages/components/2245h.htm
It says:
Recommended Enclosure Volume:225 - 450 L (8 - 16 ft3)
Does that mean I times this volume by 4 for 4 drivers?
I know nothing. I think Elliot Thompson knows this stuff.
Back to Top
Elliot Thompson View Drop Down
Old Croc
Old Croc
Avatar

Joined: 02 April 2004
Location: United States
Status: Offline
Points: 4192
Post Options Post Options   Thanks (0) Thanks(0)   Quote Elliot Thompson Quote  Post ReplyReply Direct Link To This Post Posted: 09 February 2018 at 10:19am
Originally posted by Roman Roman wrote:

Here is my initial post with lots of info. But got no responses regarding plans.
https://forum.speakerplans.com/topic99270.html
I am using JBL2245H 600W 8 Ohm speakers.
I want to build 2 quad boxes. Just like Paul Axis valvatron quad wardrobe and Dub Specialist House of Joy build.
What do I need to know? 
From my googling. My current assumptions are:
I need to consult the JBL data sheet of the 2245H and use the information to build a compatible cabinet in terms of design type, volume, tuning. ???

Yes. A speaker's TS Parameters will guide you into creating a cabinet that is aimed solely for the drivers in question thus, achieving optimum results. 

Quote
If Paul Axis or Dub Specialist gave me plans for a quad bass reflex cabinet would it be incompatible with the 2245H driver?

Custom designed cabinets aimed for a particular driver will not yield the same results using an alternative driver.

Quote
I may need to use speaker design software.

Yes. There are free loudspeaker design software simulation programs available on the market that will help you along the way.

Quote
Can someone give me the ABC's of what I should do to get this right.
Maybe make an MDF prototype before committing to 18mm birch.


I also want to make a matching double 15 the same width as the quad box that will hold 2 JBL 2226H 600W, 8 Ohm speakers.
I will have 2 Markus Klug 10 cell MK1005B wooden horns on each double 15 box. So a would have 2 identical configurations of a quad, double 15 and 2 horns. 2 quads, 2 double 15s and 4 horns total.
Retro look with recessed grills.

What would be the best amps for my setup? 



The last quotation is solely on you. There comes a time when you need to decide what is the best method for you. You are creating a custom design so you must decide which method would work best aesthetically to you.

Amplifier power requirements will always be the same. You should have an amplifier that delivers a minimum of two times the RMS rating. In the case of JBL, that would be the same power or more than the Program rating for each driver.

Best Regards, 


Edited by Elliot Thompson - 09 February 2018 at 10:21am
Elliot Thompson
Back to Top
Roman View Drop Down
Registered User
Registered User


Joined: 01 April 2017
Location: New Zealand
Status: Offline
Points: 58
Post Options Post Options   Thanks (0) Thanks(0)   Quote Roman Quote  Post ReplyReply Direct Link To This Post Posted: 13 February 2018 at 6:57pm
The crest 9001 get's a lot of recommendations.
It puts out 2200W stereo at 4 Ohms. So if I have (2) 18's per channel I would have 1100W per 600W JBL 2245H. That seems to satisfy the recommendations to have twice the wattage of amp power than the speakers RMS rating.
My friend had a dance powering (4) 18 inch speakers that I think were 600W. He had 300W shared between (2) 18s. It was a stereo amp with 300W per channel. It was ok for a little reggae dance. I found another identical amp second hand which got purchased and now he has double the power for the subs.
So he had 150W per 600W speaker. It was a little short of putting out the chest thumping sub bass. But not bad for a party.
From this experience I feel confident 1100W per 600W speaker will be more than enough.
I intend to have (4) quad 18 wardrobe cabs for a total of 16 subs. So a lot of speakers not working very hard.
Plus I abhor painful sound levels> More accurately I like to almost be able to have a conversation next to the speakers. You would be surprised. With a big fat reggae sound system not too loud you can talk close to the speakers. I would need (4) crest 9001's. One per quad cabinet.
Dang and that's only the subs ha ha.
Still got 4 double 15s and 4 horns to power.
Back to Top
Roman View Drop Down
Registered User
Registered User


Joined: 01 April 2017
Location: New Zealand
Status: Offline
Points: 58
Post Options Post Options   Thanks (0) Thanks(0)   Quote Roman Quote  Post ReplyReply Direct Link To This Post Posted: 13 February 2018 at 7:07pm
If I had to build a quad 18 wardrobe for JBL2245H's and a double 15 bass reflex cab the same width prototype out of MDF by the weekend what steps would I take?
I am assuming, just go to a custom speaker cabinet designer. Ha ha.
1. Download speaker cabinet design software.
2. Plug in the JBL 2245H data sheet specs.
Some other stuff.
Back to Top
Elliot Thompson View Drop Down
Old Croc
Old Croc
Avatar

Joined: 02 April 2004
Location: United States
Status: Offline
Points: 4192
Post Options Post Options   Thanks (0) Thanks(0)   Quote Elliot Thompson Quote  Post ReplyReply Direct Link To This Post Posted: 14 February 2018 at 9:53am
Originally posted by Roman Roman wrote:

If I had to build a quad 18 wardrobe for JBL2245H's and a double 15 bass reflex cab the same width prototype out of MDF by the weekend what steps would I take?
I am assuming, just go to a custom speaker cabinet designer. Ha ha.
1. Download speaker cabinet design software.
2. Plug in the JBL 2245H data sheet specs.
Some other stuff.


Aim for the frequency response you are seeking. For example. If your goal is 50 Hertz, you want to make sure the normalised gain will achieve 50 Hz @ 0 dB. Whatever frequency you are aiming for, you want to make sure it will be achieved using the normalised gain chart @ 0 dB

As you are building a large box, you should not have any issues reaching your aim unless, the loudspeakers are not capable of doing it. Designing the cabinet to meet your requirements is more vital than, what amplifier you want to feed the loudspeakers.

Bear in mind the coupling effect of four drivers working together as a team will eliminate a lot things other guys are seeking when they are making a small reflex box to house one driver.

Their main objective is to achieve bass in a very small cabinet. They are willing to sacrifice extension for compactness.

Your main objective is to have a constant cabinet gain from 100 Hz to the desired low frequency limitation you are willing to accept before the -3dB decline comes into play. This will guarantee you will achieve the extension you desire as you are willing to use a large cabinet in order for it to be possible. The end result is more SPL without the aid of equalisation due to using a larger cabinet in addition to, less xmax as all the drivers are sharing the work.

Best Regards,   


Elliot Thompson
Back to Top
Roman View Drop Down
Registered User
Registered User


Joined: 01 April 2017
Location: New Zealand
Status: Offline
Points: 58
Post Options Post Options   Thanks (0) Thanks(0)   Quote Roman Quote  Post ReplyReply Direct Link To This Post Posted: 14 February 2018 at 10:12am
That's all very reassuring sounding.
It makes sense to me that more drivers is going to push air easier.
I don't know what frequency I am aiming for. All of them.
It would be nice to be able to reproduce everything down to the lowest bass.
Here is the JBL 2245H data sheet:
The resonant frequency of the driver is 20Hz.
I seem to recall the bass reflex cabinet calculator saying a cabinet frequency of 17-19Hz.
The JBL recommended enclosure volume ranges from 225L to 450L. Wow! Up to double the minimum.
The desired volume of the box was the only variable I was altering when using the cabinet calculator.
450L times four was 1800L which gave a height of 1960mm. Seems too tall. I was multiplying the volume by four because of the four drivers.Half way between the recommended volumes was 1350L
Which was still 1600mm or something like that.
The photos I see on the net of quad boxes or on this site by valve a torn or dub specialist sound don't seem that tall.
I will have to consult a speaker cabinet expert locally because I don't know enough to even select the desired frequency.
Roman.
Back to Top
Elliot Thompson View Drop Down
Old Croc
Old Croc
Avatar

Joined: 02 April 2004
Location: United States
Status: Offline
Points: 4192
Post Options Post Options   Thanks (0) Thanks(0)   Quote Elliot Thompson Quote  Post ReplyReply Direct Link To This Post Posted: 14 February 2018 at 1:16pm

Building a reflex becomes more complex when you want something different than the average end user. 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, 






Elliot Thompson
Back to Top
DMorison View Drop Down
Young Croc
Young Croc


Joined: 14 March 2007
Location: Aberdeen
Status: Offline
Points: 1088
Post Options Post Options   Thanks (0) Thanks(0)   Quote DMorison Quote  Post ReplyReply Direct Link To This Post Posted: 14 February 2018 at 7:34pm
Originally posted by Roman Roman wrote:

That's all very reassuring sounding.
It makes sense to me that more drivers is going to push air easier.
I don't know what frequency I am aiming for. All of them.
It would be nice to be able to reproduce everything down to the lowest bass.
Here is the JBL 2245H data sheet:
The resonant frequency of the driver is 20Hz.
I seem to recall the bass reflex cabinet calculator saying a cabinet frequency of 17-19Hz.
The JBL recommended enclosure volume ranges from 225L to 450L. Wow! Up to double the minimum.
The desired volume of the box was the only variable I was altering when using the cabinet calculator.
450L times four was 1800L which gave a height of 1960mm. Seems too tall. I was multiplying the volume by four because of the four drivers.Half way between the recommended volumes was 1350L
Which was still 1600mm or something like that.
The photos I see on the net of quad boxes or on this site by valve a torn or dub specialist sound don't seem that tall.
I will have to consult a speaker cabinet expert locally because I don't know enough to even select the desired frequency.
Roman.

You can easily get an idea of how low you need to go by running a few of your typical tracks through an analyser - Audacity is free, has that feature and isn't too hard to get your head around for example.

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.

Smaller boxes and higher tunings will result in less very low bass (and may put a hump in the upper bass if you go too far), but will give better overall efficiency and more output (and effective power handling) before reaching Xmax.

Question - do you already own these drivers?
If not, it may well be worth looking at something else that's better suited to smaller boxes, if you find that you just can't get a practical sized box for these.

HTH,
David.


Edited by DMorison - 14 February 2018 at 7:38pm
Back to Top
Elliot Thompson View Drop Down
Old Croc
Old Croc
Avatar

Joined: 02 April 2004
Location: United States
Status: Offline
Points: 4192
Post Options Post Options   Thanks (0) Thanks(0)   Quote Elliot Thompson Quote  Post ReplyReply Direct Link To This Post Posted: 14 February 2018 at 8:05pm
Originally posted by DMorison 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 and use multiples which, is the concept of using a Quad Eighteen Box.

 

Once you move into multiple speakers playing the same frequencies, you will realise you will not need to drive your loudspeakers to mechanical failure to attain the SPL you are seeking. As a matter of fact, you will find yourself reducing the bass due to having too much bass.

 

Those who fall in the above category will understand wholeheartedly on such an experience.  

 

Best Regards,

Elliot Thompson
Back to Top
Meat View Drop Down
Young Croc
Young Croc


Joined: 05 June 2009
Location: Manc
Status: Offline
Points: 1411
Post Options Post Options   Thanks (0) Thanks(0)   Quote Meat Quote  Post ReplyReply Direct Link To This Post Posted: 14 February 2018 at 8:07pm
Do you already have the drivers? For a quad wardrobe I would have thought the 16ohm version of that driver could be quite convenient. Of course I could be wrong though.
Don't test the champignon sound
Back to Top
Roman View Drop Down
Registered User
Registered User


Joined: 01 April 2017
Location: New Zealand
Status: Offline
Points: 58
Post Options Post Options   Thanks (0) Thanks(0)   Quote Roman Quote  Post ReplyReply Direct Link To This Post Posted: 14 February 2018 at 8:29pm
I've got (2) 2245H's. I'm looking at getting old 2240's reconed to be 2245H's.
I might be designing an over spec'ed system. But it will be fun to have what I predict will be a big effortless sound. I'm hoping it will be quite an experience.

All the responses so far suggest there are preferences that have to be chosen.
I just want the best sound. I want to play all sorts of music. Hold dances with different genre themes.
But I definitely will focus on the deepest bass sound of reggae dances. Primarily it will be a reggae sound system.
Some of the advantages of the bass reflex ported cabinets vs scoops that I read on this forum were, a flatter frequency response and lower extension into lower frequencies than the scoops. She criticised scoops for producing one note baselines. IOW emphasising one frequency over others.
I want to hear all the notes of baselines evenly I am guessing.
Other sounds seem to be successfully using the bass reflex cabinet including quads.
Surely there is some ideal design that will be appropriate for my JBL 2245H drivers and give me the best sound reproduction.
Nothing lacking in the lowest frequencies and even frequencies I assume.
Back to Top
 Post Reply Post Reply Page  123>
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.01
Copyright ©2001-2018 Web Wiz Ltd.

This page was generated in 0.078 seconds.