Speaker Kits

[decibel]

About two weeks ago I asked Kay (Pavel) if I can make an offer to forum members to indicate that I have designed some speaker kits for sale. He gladly agreed, and I can now announce that they are available at present.

There are currently two options, a 2-way bookshelf and 2-way floor stander. The range will be expanded in the coming year depending on the success of this venture. The kits use Infinity Dynamic drivers, which are good entry level drivers from a local supplier, and also present good value for money as a result. Many experienced forum members have used these drivers in their own designs and seem to report favourable results so far. The kits are aimed at those who would like to enter into the DIY speaker arena and learn how to build their own speakers at a relatively affordable cost, without having to invest in expensive tools.

The kits will, for now, be made on order only, and turnaround times will be about two weeks, depending on availability of stock.

If you are interested, please go to the website at www.decibelaudio.co.za for the details on the kits. Payment is handled through the Bid-or-Buy portal at the moment, but I will accept direct correspondence from forum members through this forum.

I hope this venture will make DIY speaker building more accessible in our country, knowing that parts are hard and expensive to come by at the best of times.

Please feel free to make comments (hoping they will all be positive of course  ) and ask questions in response, and I will try and answer them as best I can.

[ghostinthemachine]

Decibel

Congratulations on your business venture.

The website layout is very professional and clear (just check that your HTML page title tags gets completed to avoid "Untitled Document" at the top of the browser).

The kits, from the photographs looks very neat and, I guess, should be fun to assemble. 

Do you plan to issue a slightly higher end kit with ie SEAS or Vifa drivers?

What about veneer kits and clear instructions to "do it yourself"?

Here's to DIY Audio!!

[iondb]

It is looking good!!  Good luck with your venture!!

[Shonver]

Well, it looks promising. I must say that the crossover is much simpler than I would have done, but it's hard to judge performance from a picture.

Kudos for:

1) The guts to take on such a venture
2) "the local market in South Africa and surrounding African countries"
3) Neat, apparently simple to assemble kit
4) CNC'd panels
5) Bracing: nice
6) Web site: nice, neat. But browser page tab reads "Untitled Document"

[Timber_MG]

Excellent, always good to see more activity in this space. I still have some of those drivers laying around gathering dust.

[decibel]

Do you plan to issue a slightly higher end kit with ie SEAS or Vifa drivers?

What about veneer kits and clear instructions to "do it yourself"?

At the moment the offer extends to two models in the Cine Series, which is aimed at the beginner to intermediate DIYer, but not limited of course. I will add a Grande Series in the coming year (no specific date yet) that will use the SEAS drivers most probably.

I will expand the website with some DIY guides in the coming months. So depending on the outcome of this venture, veneer kits could be an option for the future.

Thanks all for the positive comments so far, and for pointing out the incomplete webpage title tags!! 

[DRNB]

Decibel,
You took the step in doing what many of us dreamed of doing for many many years. Congrats, your kit looks very nice.
From one very jealous dude  (should be a thumbs up icon)

[Shonver]

I was just asking myself: So, who is decibel?. I see from the profile that you are in Cape Town. Hmmm... I'd like to meet. Where in CT are you?

[decibel]

@Shonver

I live in Plumstead, but work from a home/office in Tamboerskloof. It will be great to meet some of the Cape Town forum members! Contact me on my email address in my profile, and we can arrange to meet. Any other Cape Town forum members are welcome to join in...  

[Ampdog]

Perhaps to fill in one extra piece to the picture:

For the reasons Decibel have mentioned I also became interested in Infinity Dynamic products. With some trouble I got in touch with the factory and obtained some response graphs. They are more than reasonable. Then I 'sacrificed' one of their 10 inch models to inspect the innards. I found nothing in magnet and voice coil construction to put me off, compared to more expensive makes. (The only possible improvement I can see is the use of a copper shorting ring over the magnet pole. As an aside, I would really like some comment from Timber as to the real advantage of such without further discussion, Decibel allowing.)

So! Another aside, with my hopefully dead-practical outlook ... why only entry level?? - - I would really wonder to what degree expensive types like Vifa or Scanspeak would audibly improve a good design like this?

(In deference to Decibel, this thread should not be used to branch off on such a discussion per se. But as the question has been asked, I have yet to see the real advantage of some quite more expensive makes in practice...)

This in support of Decibel's venture.

[decibel]

@ Ampdog

First, thanks for the support!

You raise some interesting questions regarding the possible advantages of more expensive drivers versus less expensive types, which is probably a discussion for a separate thread as you mention, but I would certainly like some of the experts like Timber to fill in on a discussion like this.

That aside, to shed some light on why I call these entry level drivers (although they seem to perform very well for the price), I should rather have said 'entry level speaker kits', as the I believe the driver, enclosure and crossover combination determines the level of performance you ultimately get from a complete loudspeaker. My goal for these particular kits using the ID drivers are to be entry level units, and have thus been designed with the following criteria in mind:

- good value for money compared to entry level commercial speakers - price must be right
- it must produce good sound that is suitably balanced for both home theatre and a wide variety of music genres
- easy placement, especially close to a back wall, which makes it suitable for small to medium sized rooms
- simple crossover that can achieve a FQ response of +-5dB at least, and not break the bank!
- easy to assemble enclosure (without the need for heavy woodworking tools)

I managed to use a very simple XO for the design, and still keep the response within +-5dB. It can surely be improved by adding more XO components to tweak the response graph, but for entry level units the result is more than acceptable and hopefully affordable. I am also hoping that some who buy and assemble the kits, will at some stage be brave and encouraged enough learn more and start playing around with the XO values and add an take away, in an effort to advance the DIY speaker building community and get guys involved in this field.

[Timber_MG]

I haven't measured these up properly and what measurements I had were lost...perhaps it is time to play around with a few drivers again

The stamped production of the ID drivers' top plate (I have also vivisected one) means that BxL is lower than in a higher tolerance production series such as Seas for instance. This generally results in high Qes values in these speakers (making them suitable for sealed enclosures) and can lead to production variances if (as often is the case) the speaker manufacturer jumps between motor part suppliers (don't know about ID). Note that even scandinavian manufacturers are also not immune to this (as some Vifa tweeter buyers of 10 years back will attest)

The better drivers also will use a T-pole gap to improve magnetic field symmetry (optionally copper shorting rings) and machined motor assemblies, but one must consider the cost of manufacture. One upshot is that if you will compare the respective Seas or similar to the generic chinese type drivers is that they will have far greater Xmax for the same magnet size in addition to lower distortion due to the gap symmetry.

[Gerhard]

Sometimes you get what you pay for and sometimes you get lucky

[Ampdog]

As Timber_MG said.

I will still be 'pushing the envelope' by the following, hopefully not pulling attention away from Decibel's original purpose for this thread. Here follow the T-S characteristics of an Infinity Dynamic 20cm loudspeaker, model R8520, as determined 'on the bench' by me. (I have used several of these):

BL = 6,32 t.m   fs = 36,7Hz   Mmd = 22,1gm   Mmr = 1,5gm   Mms = 23,6gm   Cms = 8,06 x 10(power -4) m/N   Qes = 0,88   Qms = 3,3   Qts = 0,69   Levc = 1,1mH   Revc = 6,9ohm   Vas = 42 l (1,5 sq. ft)

It will be apparent that Qts is rather high for many uses, also there is bound to be a tolerance as Timber said. I did not test several examples for control.

Also to state that I am not an agent for Infinity Dynamic and have no connection with them. (In fact, I was rather disappointed by the scant attention received at my last visit to their Jo-burg agents.) But the above for comparison.   

[kay]

I can only echo the other comments on the website design - it looks great! The only thing that I'm wishing for is even higher resolution photos of the kits. Perhaps a gallery showcasing some possible different finishes would work well also. Best of luck with this venture!