Sub placement

charlysays wrote: So would you advise moving them 6ft away from the wall and moving the dj setup out from the corner along that left wall? What I'm getting from this comment is don't have the booth in a corner due to the double reflection (especially one near the speakers) and don't have the speakers tight against a vertical surface as it will cause the bass to be too ringing in a reverberant room.

Yes. Bear in mind every room is reverberant. What one has in the room determines how much of reverberation is reduced. Once you are in a high reverberant room, you want your speakers away from boundaries that will enhance the reverberation.   

charlysays wrote:   However I thought that a gap of 6ft between subs and wall would cause a delayed reflection which could cause cancellation problems?

Where would you get cancellation if you are playing one column? The sound is emitting from one direction and bouncing about in the room.  

charlysays wrote:     On your second comment, I agree that lack of definition is inevitable in a room like this though I was unable to convince one of the promoters of this. The other promoter seemed overjoyed with the sound.

The definition can be achieved by using multiple columns and focusing more on mid range and tops and less on bass. Think of the Tube. The facility consists of multiple speakers arranged to achieve intelligence despite its enormous size. This allows you to get a better understanding on what is being announced at any location.

charlysays wrote:   On the top to sub balance issue I disagree with you as I have a DSP and had enormous gain reductions on the sub output bands to keep the sound more balanced. Myself and the promoters constantly monitored this. Essentially I was only using one pair of the large subwoofers and not even running that pair near their maximum.   I was asked to turn the tops Down on several occasions, and the JBL MP415 tops with their BMS4540 1.5" diaphragms can hardly be considered a harsh compression driver. At no point were vocals etc overpowered by the bass. I fully expected the tops to not remotely be able to keep up but they too were running with significant gain reductions all night though they were running harder than the subs (which were basically idling).

This reinforces what I said…

Elliot Thompson wrote: If you only carried one column, the bass is bouncing about the entire room. You should of have at least two columns (One on opposite sides of the room) two reduce blasting a single column in order to cover a large reverb-rant room.

The above is why some requested you to reduce some of the high frequencies. For your compression drivers are piercing their ears with the bass following after. Where is your midrange?  If you have a good midrange section, you would not have found yourself reducing the compression horns and bass bins just to get some intelligence from the midrange.

This is why your setup offers the sound of a start up DJ system. The more seasoned DJs that focus on large rooms know the importance of midrange.

charlysays wrote:     I am really not sure what the problem is with the boxes in relation to the fire exit?! I am aware of the regulations and often work to them in my place of work and the requirement is that there is no obstruction to the door opening fully (these doors open outwards so that could not be an issue) or to the width of the fire exit as determined by the width of the door frame.

Have you ever found your self around people that are in a state of panic? Dare I say, 80% of those that find themselves in chaos are the most idiotic people under the given conditions. Their emotions gets the best of them and they blame every and anything that prevents them from getting away from such turmoil.  You cannot rationalise them under the given circumstances.

It is better being safe than sorry and keep your boxes away from the fire exit. If you are hearing sound men mentioning your boxes are too close to the Fire Exit, take heed to our advise.

Best Regards,

charlysays wrote: There was a reggae sound system guy there who has run reggae festivals as well as a guy whos spent time at the Bristol sound system scene and both were enjoying the sound and kept asking me to turn the bass up as he "couldn't feel his eyeballs rattling enough". I must assume he is wrong, along with the majority of people who were loving the sound. Do you not think this comes down to a matter of opinion to some degree? Some people seem to like getting rattled by sub bass more than picking out every nuance in the mid range. A minority of people with the least experience of sound systems complained about the sound. Overall I took this as a positive comment on the sound, naturally.   Is there a specific problem then with the JBL MP415 speakers that causes the compression driver to massively overpower the midrange driver even when they are not being used to full capacity? I was not aware of this and would have thought that the internal crossover should ensure that, when used within their specs that the sound should be balanced. If this is so then would you recommend another pair of 12" mid range drivers to patch the hole in the MP415 response?   I'm not sure what your idea of a "starter" DJ setup is but where I'm from that entails a pair of JBL JRX tops and no subs, being ragged to screaming with a clipped mixer. If you're lucky there might be a rattling ported subwoofer or two. Likewise the local nightclubs are not much better- screaming full range speakers and only one or two subwoofers. I'm happy to say that even with flat EQ, the JBL Mpro top half sounds far better than the majority of what I hear elsewhere at events or clubs and the 18sound loaded cubo subs provide warm trouser flapping sub bass, which is why people running such events as this hire me :)

There are some guys that are only concerned with bass. They do not care about anything else. Once they hear a good amount of tsk, tsk, following the bass line they are happy. I might add what you may consider not enough for bass can be more than enough for others when they are listening to the overall sound quality of the sound system.

Bass is like drinking Rum. The more you indulge yourself to it the more immune you become of it. One must keep that in mind whenever you hear requests of reducing the bass.

Your JBL Speaker System is a Two-way configuration. Like most Two-way full range loudspeakers, midrange is not the priority. Two-way full range loudspeakers focus on bass and treble. They work well for Weddings and Corporate events where very loud is not a priority. However, for Raves, you need to have a dedicated midrange driver. This is why the more expensive full range loudspeaker systems always offer an extra driver or two solely for midrange.

Your loudspeaker setup looks as if you stepping up from smaller events to larger events in which, you are adding larger bass bins but have not upgraded the tops. The JBL two-way full range will perform well with the JBL subs below. Such a setup is common with many Wedding/Corporate DJs in the States with an additional pole mount to elevate the tops.

However once you add an additional four Cubos in the equation, those JBL two-way speakers will have great difficulty offering the same quality in terms of midrange at high sound pressure levels.

Best Regards,

There are many Speakerplans members that fall into your category. The most we do is have a variety of tops at our disposal. This allows us to adapt according to the event we are hired for.

Since you are not fixed to one type of music it would be wise to have a variety as well. It also allows you to get more events as you are more versatile to adapt to wider market than being fixed to one type of musical style.

If you are content with the Cubos, you can just build more and carry one or twenty pending on the event. Bass is the easiest to accomplish whereas, tops will require more investigation to determine which ones will fit the variety of events you are hired for.

When you are hired for those Dogs On Acid events, it may be best using Horn-Loaded tops (Possibly Martin Black line H3+) and, for those larger posh events when you need a more smoother response, you can tote something in the range of JBL SRX 835 since you are fond of JBL. For those really small events you have your current JBLs.

Of course, if you rather build your own customised tops, you will have more leeway to design it specifically for your requirements.

Best Regards,