The Boominator - another stab at the ultimate party machine

[v-bro]

Hi,

3: With the AMP6 kit you get several resistors and there is a full description in the docs about how to configure these for certain sensitivities.

I use "AJ vented designer" for calculating enclosures, it's freeware and very simple to use...

[Saturnus]

1: I use an ancient JBL DOS program that the development department of PRO speakers used in the 80's. It's perfectly suited to calculate outdoor speakers, although a "tad" complicated.

2: There's really no compromise involved in the port/handles design as I wanted a slot type port to reduce excess cone excusrsion under resonance frequency, the size had to be large enough to prevent port noise and the depth had to be depth enough to get a good grip. If there is a compromise it's that you have to make a cut in the center brace to accomodate the port.

3: Already explained by v-bro above. I recommend 82K feedback resistors for use with an iPod nano.

I'm sorry but I can't help with the tweeter issue. It doesn't seem there's any aussie dealers for either a suitable horn driver or the high quality piezos used originally. An alternative could be to find some cheap car tweeters with high enough sensitivity (94-95 dB/W/m) and series connect 2 in place of each horn driver. Remember they require a filter if they aren't already fitted with one.

[tsnell]

Thanks heaps for your fast responses!

Ordered the amp 6 yesterday (and it has shipped already!), I probably should have held off that question until I’d had a good read of the manual! Sorry for the time waster question, but thanks for the 82k tip Saturnus.

Also have the woofers ordered from http://www.cannonsound.com.au/p/6735...-set-of-4.html
I figured I will paste these links here to hopefully help anyone (especially Aussies) looking for components.

The tweeters have me stumped. I have found these http://www.soundlabsgroup.com.au/p/V...TH+8.7+-+8+Ohm They are much more expensive than I would have liked but equate to about the same price as the ones from Parts Express by the time I factor shipping and the ever falling Aussie dollar. I have ordered from the Sound labs guys before and they had great service so these are very tempting. What do you think of the drivers? Is the efficiency way too high (I know, that sounds counter-intuitive/crazy when talking about a high efficiency system)?

Saturnus, sorry if I am asking too many questions and obviously feel free to not answer if you want to keep the info private (I know you are planning on selling these at some stage), but I have a few questions about the enclosure design.

1. The centre braces. There is very little info in the thread about these and I could not see any photo that showed them. From what I can gather they are glued to the woofers in each bass reflex enclosure to add structural rigidity. What orientation are they mounted in? Are they a rib type brace or a “shelf” type with breather holes cut in?
2. The ports. From the photo it looks like the ports are just holes in the ply (as could be achieved with a hole saw, jig saw and bevel bit router). Is this correct or are there port tubes (either prefab or custom) inside?
3. Access. The woofers are mounted with the front of their mounting flange pressed against the inside of the front baffle so, I assume, cannot be removed through the speaker holes. Do you have any provision for later access (i.e. screw on removable top panel) or is it a case of destroying the box to get to the drivers if something ever goes wrong?

I’ll be interested to hear some feedback on those tweeters but I am going to keep on the lookout for some others at this point. I’m going to download AJ vented designer now and try and get something modelled up today. Look forward to hearing from you all.

Cheers

[Saturnus]

1 and 2 will be clear when I find the CAD drawing, although it'll be a Google SketchUp drawing as I've lost the 100% correct CAD drawing in a harddisk crash.

3: Once you glued it together there's no way short of destroying the box to correct errors. So make sure to test everything before that. The amp and battery is in a servicable compartment in the middle though. You'll see on the drawings.

In regards to the tweeters. How's transport costs from NZ? I found the originally used piezos from a NZ dealer.

http://www.jansen.co.nz/product.php?b=&sku=HP100

I'll try to salvage those CAD drawings for you, been meaning to for a long time now but as you know; why procreate when you can procrastinate.

[tsnell]

A CAD drawing (or any drawing) would be absolutely brilliant!

Checked out the NZ supplier, thanks for the link, but they don't have an international shipping option by default in their checkout. I have just emailed them to see if they will ship over here. They will be perfect if they do.

The P Audio drivers arrived yesterday and I realised that I've ordered the wrong ones by mistake! I have 4 ohm rather than 8 ohm drivers. I was browsing the single driver page (8 ohm) and saw the link to “4 x P.Audio HP-10W 10 Inch 100 Watt” down the side and clicked order without double checking (I think I got over excited about saving $10 by getting the 4 pack). Stupid me. Procrastination gets a bad rap. A little procrastination, or probably more so reading the (not so) fine print, could have saved a bit of a headache on this one!

By the time the 4 ohm drivers are paralleled the impedance of each channel will be down below 2 ohms... I think the little Amp 6 might just about give up the ghost driving that low an impedance (but correct me if I’m wrong). Do you think they will be OK? I will get in touch with Cannon and see if I can exchange them.

Thanks again for your help!

Cheers

[Cal Weldon]

Can you not series them?

[col]

tsnell, You got the 4ohm ones! Last time I inquired at Cannon they wasn't available. Lucky you. I'm using amp9-basic it loves a 2ohm load

edit: just looked at that link. Out of stock.

col.

[v-bro]

Maybe you guys should plan for a swap?

[Saturnus]

You lucky bastard. I've been searching high and low for those 4 ohm versions.

But in your case having already ordered the amp6basic too. I can see the problem. There 2 paths you can take. Either praise your luck and order an amp9basic, and make a version the runs on either 12 or 24 V, selectable with a switch. Or you can curse your luck and order a second amp6basic.

The point with the amp9basic version is that you can bring it to parties where there's a ready power source and get the maximum output power of 4x60 W RMS, or switch to low voltage and 4x12 W RMS when running it off-grid on battery power.

Either way you'd get more output power but possibly also shorter battery life times but if you use the full top solar panel you shouldn't run into many problems on that account. Just bring an extra set of batteries, and a charger and you're set.

Or arrange a swap with Col above. I'm sure he's happy to take them of your hands.

[tsnell]

Hi cal & col!

Sorry my responses are a bit slow everybody I am still under moderation so they take a little while to appear.

Haha, it sounds like I really lucked my way into that one then! I was too busy being angry at myself for looking at one thing and buying another to actually think about the consequences.

“Can you not series them?” It is all going to depend on the tweeters and cross over network I suppose. The NZ supplier does not have any stock of the HP100, they have the HP1000 but can’t give me any info or a datasheet for it. So I am still on the lookout for a good tweeter option if anybody has some other suggestions?

Ordering another Amp 6 or the Amp 9 is definitely an option but I will need to order it ASAP if I’m going to make my (self imposed) deadline.

If I went to the Amp 9 would the best way to then be go to an active divider network and feed the woofer and tweeters in each of the two enclosures off its own channel?

Col, do you use your amp9 for a boombox?