Speaker Kits

[Shonver]

I don't know how much cheaper chip board is than MDF, but I would say that for the cine series you should probably look at cheaper materials and manufacturing methods (as opposed to CNC). Reserve the CNC and MDF for Deluxe, where it is better justified. Many up-market speakers use chip board with smart vinyl wrap, and the customer is none the wiser. If you use the better materials in your entry-level model, you will lose a potential price advantage.

[decibel]

A cheaper material and 16mm board instead of the current 18mm MDF will make a bit of a difference, and as you say, for the cine series and level of drivers used should be good enough. But chipboard edges are difficult to finish if you don't use veneer or vinyl, so maybe a price comparison between 16 and 18mm MDF then. Off the cuff, the difference per board is only around R50 to R100 depending on where you buy, and with my already low markup will not make much difference to the final price per set. Their are also not many other manufacturing methods versus CNC for the MDF apart from doing it manually, which from a time/labour perspective will actually be more expensive.

But I like the way you think, and will explore more possibilities to see if I can cut cost further.

[Rodney_gold]

Decibel , the only way you will cut costs is economies of scale , however the issue is that cutting costs of the speakers is not relevant unless you get em sounding right .. folk want a giant killer at an affordable price.

[decibel]

Decibel , the only way you will cut costs is economies of scale , however the issue is that cutting costs of the speakers is not relevant unless you get em sounding right .. folk want a giant killer at an affordable price.

True, and I have already indicated that cutting costs will be very difficult!

And what you are saying is exactly what I'm trying to achieve eventually.

The questions I ask then is: Is my price right (affordable) if I get the speakers with a new (better) tweeter to sound right (giant killer or as close as)? ... and, do you think from what you have heard, that the woofer and enclosure at present with a new tweeter and XO has the potential to achieve this criteria?

If not, I'll have to consider different components, but would like to know what you think though, based on what you have heard so far. I know you have already indicated that the woofer's performance have surprised you, but can it be good enough to be part of a system that is regarded as a "giant killer" with the right XO and tweeter?

These questions might be difficult to answer, but you seem to have a good ear and have heard the system and therefore your opinion is quite valuable to me at the moment.

[Rodney_gold]

I cannot really give you an answer until I have heard the speaker with a good tweeter as the old tweeter doesnt allow any of the potential of the speaker to come thru , apart from that my comments are based on tonality only and a breif listening session , there are other characteristics of the speaker that need to be auditioned  in far more detial like transient attack , imaging , soundstaging and a far more extensive analysis of microdynamics and so forth. You have got the bass right which is one of the harder things to do - so build on that foundation. Personally , I think supplying the speakers with no finish is a mistake ..speakers are the most visible component in a systems and even if they are giant killers , I think aesthetics are very important for both the owner and the rest of the family. I recon if you can make the floorstanders look and sound awesome at under 5 grand , you would have a good chance , the asking price of R3799 (as per your website) vs R4800 or so is not going to make a huge difference in terms of the market - its R1k more which is not going to be a deal breaker especially if you up the ante in what you provide.

[Shonver]

... and, do you think from what you have heard, that the woofer and enclosure at present with a new tweeter and XO has the potential to achieve this criteria?

If not, I'll have to consider different components, but would like to know what you think though, based on what you have heard so far. I know you have already indicated that the woofer's performance have surprised you, but can it be good enough to be part of a system that is regarded as a "giant killer" with the right XO and tweeter?

What is your design methodology? Did you tune by ear? This approach can work on condition that the drivers have smooth response at crossover. But some of the baddies can only be picked up by measurement.

The mid/bass can be made to sound remarkably good, but the tricky bit is integration with the tweeter. Done right, the midrange is silky smooth. This I achieved using a good (not great) silk dome Vifa tweeter that is now obsolete. The crossover was not simple, however.

[decibel]

@ Rodney,

Thanks for the reply. The purpose of the kit is for people to build themselves and to then apply their own finish. Others might want a finished unit, which is an option I will offer eventually. It's just not possible for me to give all the possible scenarios and options at the same time. Also, the kit needs some tweaking, which is why I'm having it reviewed, and then make improvements and expand on the offering as time goes by.
Adding a good finish for an extra R1000 plus labour etc. is very difficult, when you consider that the cost of building a speaker mostly goes into the cabinet and finish, and then I still have no mark-up on that yet for my time and effort. The kit offering eliminates the labour costs and markups that I would normally add, and the person finishing the kit themselves only pays for it in their own leisurely time and materials. Or you can take it to someone who can finish it for you at some cost of course, but without my labour and markup you should easily be able to get someone who can give the cabinets a decent lacquer finish for a R1000. Maybe not 100% piano finish, but very close!

But at the end of the day, as you say, it needs to sound right, so that will be my focus for now.  

Thanks!

@Shonver

I use measurement equipment and software. I also tune by ear as you can pick up some nasties in this way that measurements don't always show. Then I'll compare to other similar units if possible, and have others listen to see what they think.

One thing I have noticed is that many people prefer a very crisp (sometimes even harsh) top end FQ, where personally I prefer a more subtle top end FQ that is smoother on the ear. Noticeable often when you use metal domes versus soft domes. Maybe why my ears thought the top end level to be acceptable for what we have here. Midrange is not that open as I have heard before, but my decision to go with the XO that I did, was a compromise between getting  acceptable mids and acceptable highs. Other more complicated XO's made no real difference.

TBH, the current ID tweeter and Woofer XO integration over midrange is very good on paper, and I have spend loads of time on this using different configurations. It is simply the tweeter that does not perform great and I need a better unit. Full stop.

I have actually already sourced two Vifa units, one metal and one soft dome, which I will try. Both have very different response curves, so I'll have two options regards to integration with the woofer. At the moment I'm just wanting to get the sound right, without worrying to much about amount of XO components.

Thanks guys, much appreciate your input.  

[decibel]

After about 4 months in development, I am pleased to announce that the 1st new Decibel Audio speaker kit is available as of now!



As many of you might already know, the original kits, using local Infinity Dynamic drivers were pulled from the market. The reason is found in the build quality of these units. Not only did some units arrive damaged, but some of the rubber surrounds were glued on skew. I was not prepared to bring a product to the market that displays these qualities, and resorted to import quality drivers from abroad and start from scratch, rather than bring the original kits up to standard.

(I am still of the opinion that the ID drivers are good performers in sound quality when implemented correctly, but in providing a quality product to the market, consistency and good service is of more importance).

The new drivers I have chosen are all value leaders in their category, of good build quality and perform very well indeed.

Currently there is one model available, a MTM floor stander (CF552-Kit), with a matching center channel (CC552-Kit) to be added before the end of April.

I will also post some 'enclosure assembly' and 'veneer guides' on the Decibel Audio web site in the coming month to assist DIYers in finishing their units.

More info here: http://www.decibelaudio.co.za

[JacoP]

Good to see that you have changed to better drivers. Congrats!

I have also used the ID Drivers before, and I do not share your opinion of these. It appears that there is no QC at the factory and their TS Parameters are also not consistent at all.

It shows in the price of their drivers as well as being local and making use of inferior components and skills.

[decibel]

I would like to ad that if anyone lives within a 50km radius of the Cape Town CBD, and is interested in the kit, that I am willing to bring the kit and do a demo at your premises.

A kit is also being sent to AVSA Magazine, so hopefully we will have a professional review soon.

[decibel]

Below are in-room response graphs of the CF552-kit MTM floor stander. Please keep in mind that the response is not accurate below approximately 200Hz due to the gated measurements taken.

[decibel]

With the Cine Series MTM floor stander having been sent to AVSA magazine for review, and the matching center channel and 2-way models on their way, I am starting to consider working on a Grande Series of DIY speaker kits.

The Grande Series is to use higher end drive units, most probably from the Vifa and/or Seas stables, and offer a range of units in the R7500 to R12000 price range approximately. The idea then, that these models should be comparable to commercial offerings in the R15000 to R25000 price range or more.

My question to the forum members is this, "What type of speaker would you like to build if you should consider a kit as an option?"

My personal preference at this stage is perhaps a transmission line enclosure for a start, but I would like to hear your input and thoughts before further development takes place.

[Byrd]

My question to the forum members is this, "What type of speaker would you like to build if you should consider a kit as an option?"

My personal preference at this stage is perhaps a transmission line enclosure for a start, but I would like to hear your input and thoughts before further development takes place.

Take a look at something like the Seas Thor / Odin. They are exactly the same crossover and driver wise. Cabinet is different. This makes it more flexible for those with limited space.

[decibel]

I would just like to extend a big thank you to Joel Kopping and AVSA magazine for the great feature and review in the AVSA August and September 2010 issues.

Joel has done a fantastic job of assembling the CF552 floor stander kit, and also of finishing it in paint. It will be given away as a prize probably in next months issue.

The XO has also been updated to it's final version since the review, and the improvements in the top harmonics now adds even more openness and clarity to the upper-mids and crispness to the treble. Frequency response between 600Hz and 10000Hz is now within +-1dB of the reference axis, and overall response within +-3db between 41Hz and 20000Hz.

This has turned out to be a very good speaker, and can now very easily be compared to commercial offerings of 2 to 3 times the price!

If anyone is interested in listening to these floor standers, please drop me a PM. I am willing to travel as far as 100km from the Cape Town CBD to demo a set at your convenience. I am also currently working on creating some kind of presence in the Gauteng area, but maybe Joel will allow you to listen to the set he has during the course of this month before it goes out as a prize.

[WaterDog]

Fantastic review and great to see recognition for your work - congratulations and hope the orders roll in! If you're ever in the Paarl area I would definitely be interested to hear them on my system.
Regards,
Wes.