Bass Bins & Crossovers

[Clockwork_Orange 0]

I am looking at setting up a second outfit, and the problem I have is with speakers. I have a pair of Soundlab speakers with 5 tweeters, a horn and a 15" driver. I have replaced the driver with a Gemini one to increase quality and also increase the power handling capabilities and all sounds well. However, becuse the driver has gone from 100w handling to 150w handling, should I have changed the crossover (assuming there is one - I didn't look and being cheap speakers there is always the chance of there not being one I guess). If so, how?

 

Secondly, again to increase overall handling, volume and wuality, I am building a pair of bass bins with scoops using Celestion or Fane 15" bass drivers (not sure which yet). Do I need a crossover and what sort of ratings should I be looking at? To my mind, I am looking at additional bass as opposed to a subwoofer - or am I just totally on the wrong track?

 

All answers in nice simple terminology please so a dimwit like me can understand!

 

Incidentally, on my previous query about switch noise I ordered the components recommended by forum members, fitted them and they are now noiseless - thanks everyone!

 

Aaron

[ChrisPointon 0]

Don't forget that your soundsystem and speakers are only as good as the weakest link in the chain, and the power output is only as high as the lowest rated component. A bit like putting a Fiat Panda engine into a Rolls Royce - it may look ok until you start it up and use it, and then all it's weaknesses become apparant.

 

A 50w power increase isn't really worth the hassle of an upgrade if i'm brutally honest with you, and by the time you've replaced all of the components in the speakers with new uprated ones your probably half way towards the budget of a pair of 300W new ones!.

 

What some DJ's also forget is in the design of the speakers, these were originally designed for 100W handling and so the cabinet itself would have been designed with this in mind, so upgrading to 150W may not sound any better, and ultimately no louder.

 

Speakers just aren't about wattage, believe it or not to the human ear and contrary to popular belief a 300W speaker will not sound twice as loud as a 150W one, in reality if its poorly designed it may sound even worse.

 

Another important factor to consider in speakers is it's cabinet design and the quality of components, and between them these result in SPL figures. SPL figures are just as important as wattage figures, and more so when it comes to loudness. In simple terminology think of SPL figures as a form of efficency rating, the higher the rating, the more able the speaker is at converting each watt into usable sound.

 

Get a fairly decent amplifier, powering a speaker with good quality internal components and a high SPL figure and you'll be onto a winner, even if the system is medium range in terms of price. http://www.dj-forum.co.uk/html//emoticons/thumbup.gif

 

For example, a 250W speaker with an SPL figure of 124db will sound far louder and clearer than a 250W speaker with an SPL figure of only 93db.

 

On a personal level I consider Soundlab to actually be a better brand than Gemini when it comes to some speakers in the range, but I would hazard a guess that both drivers are well below 100db when it comes to SPL figures, so you haven't really upgraded in terms of loudness, quality or SPL levels. You may have slightly higher rated components, but when you listen to it, you'll probably find that it's not much louder, if at all.

 

Again with regard to building Speakers, I would buy these rather than attempt to make my own because once again the cabinet, how it is ported, the internal volume and the speaker driver parameters all come into play and thats Jodrell Bank technician and Carol Voderman territory http://www.dj-forum.co.uk/html//emoticons/smile.gif . Get one area wrong and it may well end up sounding pants.

 

With speaker prices dropping, and quality even on some budget brands increasing its false economy to embark on the DIY route where speakers are concerned. Take a look at the equipment reviews section, you can find some good reviews of speakers at good prices.

 

ps - glad the contact suppressors solved the problem. http://www.dj-forum.co.uk/html//emoticons/smile.gif

[superstardeejay 0]

Talking of soundlab speakers, does anyone know who makes the new NJD speaker range?

 

[Andy Westcott 0]

Quote from Chris:

"the cabinet, how it is ported, the internal volume and the speaker driver parameters all come into play and thats Jodrell Bank technician and Carol Voderman territory"

 

I'll agree with that.

Only build your own cabinets if you know exactly what you are doing, and have the necessary test equipment and know your maths. Porting cabinets is not an exact science, despite the books telling you it is, and you will need a signal generator, access to an anechoic chamber and a SPL meter to determine the correct port dimensions - maths will only give you a ball-park figure.

 

Another quote:

"its false economy to embark on the DIY route where speakers are concerned"

 

Generally true, unless you require something that just isn't available for sale out there.

I build my own speakers, and always have done, but it is not for the faint-hearted if you are designing something a bit better than the run of the mill stuff. Trust me, I speak from experience. http://www.dj-forum.co.uk/html//emoticons/rolleyes.gif

 

Regarding your question about crossovers, this will only possibly need changing if you change the high frequency units for something else with different characteristics, or the new speaker has a different impedance - i.e. 4 ohms rather than 8 ohms.

[norty303 0]

I also 'roll my own' so to speak and you don't have to go down the whole design path yourself. there are a number of great, well proven designs out there using easily available components which won't kill the bank.

 

Try:

 

www.speakerplans.com (and check out the forum for lots of good knowledge) in particular look at the X15, a 15" and 1 or 1.5" compression driver (a couple of options there) full range or mid/top cab. I've got some to the original design which i love but they've now been modified so they're a bit smaller and can double as a monitor wedge if needed. Not too heavy either due to using the Neo drivers.

 

and

 

www.speakerstore.nl

 

 

Walt who runs speakerstore has currently got some phenomenal bass horns (Punisher) and matching tops (Xtro) which a lot of people in this country are starting to build. Perhaps not the sort of thing for mobile DJ's but worth a look for curiosity's sake! :)

 

A friend is just completing a mid/top project comprising all horn loaded 12", 6.5" and 1" (a bit similar to some of the Martin configs, but fully horned) using a prefabricated 12" horn section (Porn Horn commercially) which should achieve a minimum sensitivity of 107db at 1w/1m across all the sections. Quality should be fairly impressive too due to the dedicated high mid driver.