Wharfedale Boombox project

[Owenf]

Taking inspiration from JimmyJimmy's Bt boomboxes I'm taking the leap and building my own boombox.....

Parts I already have:

Wharfedale AT-400 speakers - 4 x 8" 150W with 2 x tweeters
All the Wharfedale speaker bits including the crossovers, bass ports, sound foam etc.
Kenwood KAC-642 amp - 4 channel, 160W
Kenwood KGC-4032 EQ and amp - 40 + 40W
Ipad Mini
Sure BT receiver (on it's way)

Parts I still need:
LiPo batteries 12V 20AH
Volt meters
All the usual cables and connectors
Switching panel
USB port panel
Vinyl covering
Cabinet wood, fixtures, etc.
Cabinet handle
Speaker protectors - not sure how to achieve this.

I've been working on the box dimensions and have settled on 90cm (w) x 60cm (h) x 20cm (d). To get as close as possible to the volume of the original Wharfedale speakers I'll be dividing the box in half along the horizontal. This maximises the volume and replicates the 2 original speaker boxes lying on their sides on top of each other.

For wood I'm trying to stay away from MDF and go with Plywood. I want the box to be portable but not flimsy so still tossing up on the thickness.

I've made some items before - racing simulator, half size arcade cabinet etc. so hopefully this one will come off ok and I won't let the smoke out.

 

[T-STER]

Interesting project and look forward to following this

 

[jimmyjimmy19702010]

Using existing, professionally designed speaker cabinets - drivers / tweeters / crossovers and replicating the cabinets volume and bass ports sure makes the whole process much simpler and predictable.

Most project builders really can’t be sure how the speakers, crossovers and cabinets they have chosen separately are going to sound together until after completion of the build.

For my V5.0 build, I looked long and hard to find 2 way floor standers with 8 inch woofers, silk dome tweeters with between 4-6 ohms and high sensitivity - never found anything at the right price so I started from scratch. The only items that were designed to go together were the Krix tweeters and Krix crossovers that we’re designed to suit 8 inch woofers.

Looking forward to the updates.

James......

 

[Fatdog]

Hurry up already!

 

[floyd]

Awesome, if you want to trade that eq I have a Kenwood 9044 digital DSP crossover with sub output.

 

[Reli]

That's probably gonna weigh over 50 lbs...... So, portable from the home to the car maybe

 

[jimmyjimmy19702010]

It’s a very delicate balancing act making a build achieve your performance goals without it turning into a huge, heavy thing that ends up sitting in the corner.

Often, the heaviest parts of these builds are the drivers. The real secret to reducing weight is the utilization of speakers with neodynium magnets. Kilos can shaved off instantly but the speaker costs goes way up when compared with regular magnet style drivers.

 

[Owenf]

Awesome, if you want to trade that eq I have a Kenwood 9044 digital DSP crossover with sub output.

Sorry, hanging on to this one. Aim is to maybe have it under the iPad mini so it represents the control buttons under a tape deck.... that's the idea anyway.

That's probably gonna weigh over 50 lbs...... So, portable from the home to the car maybe

I have a feeling it may be not so portable, or I need to include it in my weight training regimen. If I can get one picture with it on my shoulder then I'll be happy. Looking at Box dimensions of around 850x550x200.


I powered up the amp and all seems fine when tested on one speaker. I haven't powered up the EQ yet and am getting a headache from thinking about how to wire them up to each other and the speakers. Will save that till the end.

Next steps were to get some wood and fasteners. Off to the local Bunnings. Receipt and pix for any that want more reference on the build parts:

4 x 1200x596x12mm BC Plywood sheets
2 x 2400x42x19mm pine runners to use as cleats and strengthening
2 x packs of countersunk black screws for outside cab
1 x pack of button tops for inside the cab
1 x Sikabond PVA glue

Next steps are to mark out the wood, cut, and start building the box.

 

[jimmyjimmy19702010]

See guys?! This is how you commit to a build! None of that endless ‘planning stage’ garbage and ‘project holding pattern’ b u l l s h i t

Just go out and buy the bits you need and crack on.

 

[Owenf]

Ok, here's the mockup. I'm thinking I will trim the height a little and probably not use the plastic that sits between each speaker. I'm looking to cover the front panel in a purple carbon fibre which will hopefully set off the black and grey of the other parts. I'm sure I will change my mind every day until I am ready to wrap it.

 

[Northerner]

Interesting build. Love the racing simulator, that’s a work of art

 

[Owenf]

Interesting build. Love the racing simulator, that’s a work of art

Thanks Northerner. Here's a another shot of it from the front. I made this one out of MDF with 2 hardwood skids (took 3 people to lift it), genuine car seat, race harness, 5.1 sound. It was great fun but I rarely used it and moved it on to a young whipper snapper. Painted it in 2 pac and despite putting up plastic drop sheets and sealing the painting area I still had a red mist and dusting throughout the man cave that took months to get rid of.

 

[Fatdog]

It's probably me just being nitpicky, but I would move the tweeters to the outside in a small attempt to increase what stereo separation there might be. However, if you are going to mono the box, I don't guess it really matters.

 

[Reli]

It's probably me just being nitpicky, but I would move the tweeters to the outside in a small attempt to increase what stereo separation there might be. However, if you are going to mono the box, I don't guess it really matters.

I agree

I would also add a vertical internal split, to provide better separation between the left and right channels. In fact most people use 2 vertical splits, to create a separate compartment for the electronics and battery.

 

[blu_fuz]

You done yet?!

 

[floyd]

I'll give you credit , you don't think small lol.
That actually reminds me of some of the old school car stereo display stands.

 

[jimmyjimmy19702010]

So by having the boombox split horizontally (internally), you’re going to have both tweeters and mid range drivers in the top cabinet and the two bass drivers in the lower cabinet??

I’ll be interested to see how you manage to tune the ports when you consider the added complexity of the varying internal volume caused by having different sized internal components like a battery in the lower cabinet and a much bigger amp, equalizer and BT receiver in the upper cabinet!?

I’d be inclined to split the Boombox vertically and have a centre partitioned area for the electronics. I know you were concerned the area could represent a waste of internal volume but if you build around the components, you could make it a nice tight fit. You wouldn’t be loosing much internal volume over what you’d loose by having the electronic components inside the tuned cabinets.

That way, you could utilize the original Wharfedale cabinet tuning by having a single mid driver, bass driver and tweeter sharing the same single airspace as per the original speaker design.

By having the guts in a centre section, you’ll no longer need to have ‘airtight’ installations of the iPad, equaliser, volt meter, USB panel, charger input etc in order to maintain cabinet tuning. (Think Bumpboxx Freestyle side control panel airleaks).

Just thinking out loud.

 

[Owenf]

Good points. With the horizontal split I am trying to maximise the internal volume of the box. If I use a vertical split for the internal electronics then I think I will lose too much air volume inside the speaker cabinets.

The speakers will be separated as they were originally except that both tweeters will be in one section. I thought this would be the best compromise for air volume and making the thing portable. I don't have any experience in cabinet tuning so happy to take some advice here. I do have the original air ports from the Wharfedale speakers and they are pretty large. If I change the size of the ports will that change the tuning? If there is an air leak does it render the ports useless? I'll have cabling going between the two sections.

Other thing is that the internal components kinda take up some room. I'll have the amp which is the largest, then the EQ which stretches towards the back, and the crossovers from the speakers are all hogging space. This is why I am looking to try the co-habitation route.

 

[jimmyjimmy19702010]

Co-habitation is going to cost you volume anyway. A huge amp, equalizer and battery sure increases the difficulty factor when trying to minimise spacial requirements.

The whole idea (a great one by the way) of using pre-made speakers is to take advantage of the Wharfedale factory tuning. As soon as you mess with the internal cabinet volume, speaker placement etc, all of that goes out the window and you’ll have to start from scratch. That’s perfectly fine if you’re willing to spend the time to do the vital calculations when going down the ported route.

The only issue you will have is the possible lack of vital speaker stats you will need to enter into the online calculators to work out volume, port length etc. Without those numbers, you’re flying blind and will have to resort to the dreaded trial and error method.

I’d do anything possible to be able to retain the factory tuning.

And yes, air leaks will cause your tuning to go out of wack causing loss of bass performance.

These are the factory specs of the 8 inch drivers in the V5.0. You’ll need the details of your speakers to accurately calculate your ports:

 

[Owenf]

Ah, I see. I don't think I've explained myself fully. I'm already reducing the volume from the original speaker sizes.

Originally they were: 80x25x25 = 50000 each
My one will be 85x55x20 = 88000 total, then divided in 2 horizontally = 44000 each, and then further reduced by the space taken up by the components that share this area.

This is the compromise I am trying to make to still have the unit portable. Can you tell me what difference this reduction in air space will likely make to the sound - muddy bass, no punch or ?????