Hello all BH owners,

I'm still new to this swiftlet farming thread. My dad has a 2-year-old BH which yields ~1.8kg of bird nests every 4-6 weeks. The BH occupies 2 units (floors) of his shops. He's just a passive 'farmer'. It's his friend who manages the BH for him and they split the harvest.

I'm interested to try building my own BH without relying on a third party like my dad's friend. I've read the book by Dr. Christoper Lim and would like to get my hands dirty. Next to my dad's existing BH, there's still a vacant unit (top floor) belongs to my dad. I suggested to him to allow me to use the unit as my testing ground. He's very sceptical because I have zero experience in this. So I'm going to gather more information and re-propose the idea to him. I have a few noob questions as  following:-



That's for now. I hope any kind souls here will be able to help with my questions. I apologise in advance if my questions have been asked before in this thread.

Thank.

DIY is a great idea if you know what you are doing !  I know something about construction, engineering, draughting, local bye laws, contracting and building BHs but I still employed a contractor !

As WW expressed, supervision of especially foreign labour is a pain in the neck and probably worse. Pilfering, absenteeism, fights, holidays...need I say more? 

My workers got raided by immigration and the contractor had to pay off the right people otherwise the fine would be in access of the profit ! The local malays "ajar" my indon worker and the contractor had to send a bloody, half dead person to hospital at 3am. Another had a falling wooden beam split his head open and had to be sent to hospital in a terrible mess. All this the contractor dealt with and work on site was never delayed !

Some of us get into the BH business because we do not have to deal with personnel, epf, socso, management etc. etc.

So be wise, learn from Wise Wing 

My experience is, even "supervising" the building contractor is a big headache for me already. My BH contractor has multiple jobs in hand when he build my BH. He play "now u see, now u don't" game with me. Sometimes he send 1 or 2 workers to my work site just to entertained me.  A promised 4 months completion time delayed to 10 months.

Don't pay up front. Only pay the part that is completed. Always have alternatives available and make it known to the contractor that you can always give to job to someone else.

Better still, get hold of their balls and squeeze.....make them pay for goods supplied and you delay payment until they beg you.

Thanks for your response.

In fact the west side ceiling is actually always hotter than the east side ceiling and yet there are nests on the west side. 

On the east side, most of the ceiling is about the same temperature but the sections near the east wall remains empty but the sections near the well(centre ) is occupied by many birds..

I'll monitor the temperatures more closely to see if there is a difference at the nesting planks.

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Added on September 11, 2010, 11:25 pm

Unfortunately you cannot mix tweeters of different resistance ie. ohms.

If you drive a normal piezo tweeter in parallel with a coil tweeter of 8 ohms, you will get no sound from the piezo tweeter  as all the current will be used to drive the 8 ohm component.

If you try to drive many 8 ohm tweeters in parallel, you'll likely blow your amp.

If you try drive many 8 ohm tweeters in series, you will get no sound. 8 ohms speakers need high currents to function but produce good bass sound.

Not all coil tweeters are 4 or 8 ohms.  Coils used in piezo tweeters are actually "crossovers" used to divert all the energy into the higher frequencies meant for the tweeter.

Look at the tweeter specs. carefully and it'll state the Ohms rating.

The beauty of high ohms piezo tweeters is that we can wire hundreds of tweeters together in parallel and get sound from them without blowing the amp.  Why ??  the total resistance of components in parallel is found by adding the reciprocal of each component eg. 1/r1 + 1/r2 +1/r3 = 1/R  where R is the total resistance of the components r1, r2, r3 in parallel.
so if r1=r2=r3=8 then 1/8 +1/8 +1/8 = 3/8 =  0.375 or approx. 1/3 so the total ohms will be approx. 3 ohms which will readily blow the amp up.

With a piezo which is about 4000 ohms 1/4000 + 1/4000 +1/4000 .......(for 100pcs) = 100/4000 = 1/40  so the total ohms  for 100 pcs of tweeters of 4000 ohms impedance  in parallel will be 40ohms. Most amps are designed to drive at a max current through 4 or 8 ohms so 40 ohms in this case will be the safe. Piezos need very little current to function.

There are many sorts of Motorola tweeters and some are actually coil driven, ie they rely on magnetism created by the coil when the amp current flows through it. Piezos are different in that the voltage across 2 crystal plates cause the plates to vibrate according to the voltage fluctuations.  You will find no magnet in a piezo tweeter. A coil driven tweeter will not last long in a BH.

Hope that helps.

The problem is he tricked me after 20% into construction by saying not enough money to buy building materials and need to wait for payment. I was tricked, I gave him advance to buy building material because I want my project to proceed. He actually used my advance to help finance his other projects. Lesson learned.

As I mentioned that you need a detailed agreement to safeguard yourninterest. Everything should be stated in B&W like when the completion date, the daily penalty for late delivery, the withholding securitiy in form of cash, and although it cause a little more to have a greement made but I think it is worth in gold when you experince the delay like you did. A promised that your BH will be ready in 4 months may take a few years and nothing you can do without an agreement.

In this trade, time and opportunity is money and whether you made it or not also depend on timing. Early bird catches the worms like they say...........

Thanks tuckfook, I think I understand what you mean. My BH is not big and I plan to put 50pcs tweeter for each floor. So 50 x 3 =150psc only and I will be using both the channel from the amp to powered the tweeter. My problem is the external tweeter usually go bad first and its not like totally no sound only it will sound bad. I know I will need to get my hand dirty to really find the solution. I suspect the cheap capacitor is the fault here. Thanks again.

p/s. I only used 8 ohms tweeter for external and all internal is 4 ohms.

Happy Malaysia Day everyone!!!

Hi Guys

I have been following this forum for a while. Happy Malaysia day. It is good to have another public holiday and a good rest.

managing contractors is really key if you want to have your birdhouse completed on time. The contractor will usually start work quickly, they will do all the diggings, and what not until they have done sufficient "damage" that you are committed to them. They will then disappear to attend to other jobs that they have previously disappeared from when they came over to work on your project. They will re-appear again after many many calls and threats from you. They know that you are at their mercy and will entertain you at their own pace. Most of these contractors work on a couple of projects at the same time and have no qualms about starting on any other new jobs while have a few of their customers towed along by the nose.

Jackie

Hi Tuckfook,

Any recommend brand and models of external and internal piezo tweeters?
Thanks.

Hi Tuckfook,

Any recommend brand and models of external and internal piezo tweeters?
Thanks.

What ? you trust chinese brands ? You can put your own brand on tweeters from most chinese manufacturers !

Choose one with thicker plastic body and the largest advertised wattage !  Large wattage means bigger piezo crystal. Thicker body means the body lasts longer. Frankly, regardless of brand name, they are all almost the same. As time passes, the quality in general is getting better.

In my next BH I'm going to install all the tweeters in the corners, as in a corner piece, and cover it with fine stainless steel  mesh. So when the birds build their nest in the corner, which they will almost always do, they will build on top of the mesh and therefore no 90deg. nest.

Thanks for all comments; Tuckfook, Mfyapp and WW.

I still haven't  found a good piezo tweeter.
Most of them in the market gave voice at high frequency. If with condenser/capacitor, voice will be even higher.
I want speaker that can play at 1500 hz- 20000 hz., which will give more natural sound than only the high frequency sound.
Those magnetic speakers can cover the required frequency range, but there are at much higher price. Not easy to install them correctly too.

You are right mfyapp, if we can test the sound as it will be in the BH first, that should be the best way for speaker selection process.

Any recommendation for the right piezo tweeter will be highly appreciate.
WW tweeters, sound good, what is the specification?

Thanks for all comments; Tuckfook, Mfyapp and WW.

I still haven't  found a good piezo tweeter.
Most of them in the market gave voice at high frequency. If with condenser/capacitor, voice will be even higher.
I want speaker that can play at 1500 hz- 20000 hz., which will give more natural sound than only the high frequency sound.
Those magnetic speakers can cover the required frequency range, but there are at much higher price. Not easy to install them correctly too.

You are right mfyapp, if we can test the sound as it will be in the BH first, that should be the best way for speaker selection process.

Any recommendation for the right piezo tweeter will be highly appreciate.
WW tweeters, sound good, what is the specification?

Hi Tweeter,

Please refers to the comment on Bullet Bazooka. Those comments were written by users.

Bullet Bazooka CommentsBullet BAzooka Comments.

I am in the process to build another BH. This time round, I am going to use good internal tweeters for my BH. I have calculated the cost and is only RM1K extra for 1 floor. If the results proven working with 10% increase in nest compare to normal tweeters, then I can easily get back my money. Remember we are talking about something like compounded interest.

On the other hand, if the results so so only, you only pay extra RM1K. Maybe less than that as the quality of tweeter is better and require less maintenance.

Everything seems to round in a full circle.

Long ago, well maybe not too long but about 10yrs ago, many went the hi fi direction and it then progressed to the cheap piezo tweeters. Now are we going back towards hi fi ?

Hi fi will require better amps and all the better amps and magnetic hi fi tweeters do not last.  The anticipated better population of birds did not happen. Consultants sold sound systems worth tens of thousands of ringgit.

Many people are successful with cheap piezo tweeters and those who started with hi fi equipment changed to cheap piezos, so what does that show ?

If the BH is built wrong, no matter what audiophile equipment you put in will not help. If it's built perfect, if ever possible, it will probably require no sound at all.

In the olden days, badly distorted tape recordings with background sounds of car horns, people talking, etc. etc. worked well enough to turn some people into millionaires. Nowadays, the recordings are far superior and amps are far superior with tweeters that are better than those of yesteryear, has it made much of a difference ? Did the birds leave the old houses to new houses with Hi Fi sound? Do those with hi fi sound attract more birds?

All animals have a range of hearing, what is not within the range is simply not heard ! What we hear as being better might not even be heard by the birds and what we perceive as bad (or don't hear at all) may be whats attracting the birds.

Which brings us to the con artists who tried to sell Ultrasonic equipment and claimed that it would be better for our environment as well as calling the birds. They tried to influence the local councils to enforce the usage of such gear thereby banning the use of tweeters and conventional sound !  Some people were easily fooled to part with their money !

As far as I have experienced, the birds do not seem too fussy about the sound quality but more on what the sound is about. Only if we could understand  them.