How to choose correct Drivers for DIY speakers? need advice

+ close to 80% cabinet design and whats inside it (other than the driver, cross-over, wire qualities)

Design should be holistic and have your design parameters freezed to the approach. All parameters play equal importance including the room where you will be placing the speakers. Usually speakers are considered the weakest link in the entire audio chain because of its various design constraints and other inter-related parameters affecting the overall SQ.
 
Well thats what I thought too.
But there are people who buy DIY kits, assemble them and sell them. I was mentioning them..

Wow! I did nto even know this business model existed.

Personally for me its difficult to design a good bookshelf (sealed or Ported) given the constraints of drivers, enclosure size, cross-overs etc compared to that of a TL due to tight tolerance.

What I meant was was that there are plenty of Bookshelf speakers that are very good.

Instead of crossover,I just placed a capacitor in series with tweeter.Both Drivers were connected parallel..

Dr. Amar Bose did that too only thing he called the product the "Bose 301" ;)

Usually speakers are considered the weakest link in the entire audio chain because ....

In my view speakers are the weakest link in the audio chain (or one of the 2 weakest links) because they convert electrical energy into mechanical energy. Whenever you convert energy from one form to another there are losses and distortion.

Hari have you heard of Lou Hinckley and Daedalus Audio?
Daedalus Audio High Efficiency Speakers
 
:) ... your very own SSS440 is a 3-way FS ..... :p

Yes its a 3 way FS but it does not have any cross-over for the woofer and the tweeter (its solid-state). There is only a single capacitor (4.7mfd) in the mid-range. Hence its mid-range was harsh sounding but quite open. Now it is lying in the attic not used since past 15 years.
 
I think doors66 has covered it very well. If you are still interested in DIY after reading his post, your first project should probably be a reasonably priced pre designed two way bookshelf. Here you just need to construct the enclosure as per the design and provide stuffing.

Another thing to note is that your preference should dictate the kind of driver materials that are used. What I have read till now seems to indicate as a fact that the midbass driver material affects the sound character. So seas metal midbass will not sound like paper coated Scanspeak midbass. The best I guess are the poly cones from Audio technology.
 
So seas metal midbass will not sound like paper coated Scanspeak midbass. The best I guess are the poly cones from Audio technology.

I have experienced a long back when I checked similar car speakers(case,magnet,make)with different cone sound considerably different.So I am trying to check if I can demo some DIY speakers to get confidence.
 
I have experienced a long back when I checked similar car speakers(case,magnet,make)with different cone sound considerably different.So I am trying to check if I can demo some DIY speakers to get confidence.

If you want to carry my DIY bookshelfs from my home you are welcomed to do so. I am not anyway using it. Its better you audition them and get yourself decided with the DIY way before you freeze. You can call me today if you wish. I am on vacation from tomorrow for 15 days.

Cheers,
 
I made this post not long ago on another forum.
"Many years ago (early 90s) I was visiting a rather well known speaker designer. In his lab I saw a rather simple 6" 2 way speaker half finished. I was surprised that there was a electrolytic cap in the tweeter circuit so obviously I asked. He said the cap's sonics were part of the design and when he removed the electrotytic and replaced it with a "esoteric" cap of the same value the speaker did loose it's "danceability". After that experience I dont question methods of people who know far more than I do. There is a method in their madness. In the end it is the music that matters. "

Lastly. Perfect sound is subjective. We all have our opinions.

I think this is a brilliant point, my father used to swear by paper capacitors and used them all over his DIY cross overs. However I always preferred to use a simple 10mfd electrolytic while coupling my tweeter (during my DIY days). Thought the highs sounded more "aggressive" but "smooth".
 
All said and done about drivers and cross overs, never undermine the importance of the baffle. Ideally speaker design starts from here. Choose your baffle design first, then based on that, choose the type of drivers you'll need and then the cross over (whether the drivers are chosen first or the cross over is chosen first is a matter of debate).

Here's a snippet from the wikipedia description of a loudspeaker. It talks about speaker efficiency and sensitivity:

Efficiency vs. sensitivity

Loudspeaker efficiency is defined as the sound power output divided by the electrical power input. Most loudspeakers are inefficient transducers; only about 1% of the electrical energy sent by an amplifier to a typical home loudspeaker is converted to acoustic energy. The remainder is converted to heat, mostly in the voice coil and magnet assembly. The main reason for this is the difficulty of achieving proper impedance matching between the acoustic impedance of the drive unit and the air it radiates into. (At low frequencies, improving this match is the main purpose of speaker enclosure designs). The efficiency of loudspeaker drivers varies with frequency as well. For instance, the output of a woofer driver decreases as the input frequency decreases because of the increasingly poor match between air and the driver.

Driver ratings based on the SPL for a given input are called sensitivity ratings and are notionally similar to efficiency. Sensitivity is usually defined as so many decibels at 1 W electrical input, measured at 1 meter (except for headphones), often at a single frequency. The voltage used is often 2.83 VRMS, which is 1 watt into an 8 ? (nominal) speaker impedance (approximately true for many speaker systems). Measurements taken with this reference are quoted as dB with 2.83 V @ 1 m.

The sound pressure output is measured at (or mathematically scaled to be equivalent to a measurement taken at) one meter from the loudspeaker and on-axis (directly in front of it), under the condition that the loudspeaker is radiating into an infinitely large space and mounted on an infinite baffle. Clearly then, sensitivity does not correlate precisely with efficiency, as it also depends on the directivity of the driver being tested and the acoustic environment in front of the actual loudspeaker. For example, a cheerleader's horn produces more sound output in the direction it is pointed by concentrating sound waves from the cheerleader in one direction, thus "focusing" them. The horn also improves impedance matching between the voice and the air, which produces more acoustic power for a given speaker power. In some cases, improved impedance matching (via careful enclosure design) lets the speaker produce more acoustic power.

Typical home loudspeakers have sensitivities of about 85 to 95 dB for 1 W @ 1 man efficiency of 0.54%.
Sound reinforcement and public address loudspeakers have sensitivities of perhaps 95 to 102 dB for 1 W @ 1 man efficiency of 410%.
Rock concert, stadium PA, marine hailing, etc. speakers generally have higher sensitivities of 103 to 110 dB for 1 W @ 1 man efficiency of 1020%.
A driver with a higher maximum power rating cannot necessarily be driven to louder levels than a lower-rated one, since sensitivity and power handling are largely independent properties. In the examples that follow, assume (for simplicity) that the drivers being compared have the same electrical impedance, are operated at the same frequency within both driver's respective pass bands, and that power compression and distortion are low. For the first example, a speaker 3 dB more sensitive than another produces double the sound power (or be 3 dB louder) for the same power input. Thus, a 100 W driver ("A") rated at 92 dB for 1 W @ 1 m sensitivity puts out twice as much acoustic power as a 200 W driver ("B") rated at 89 dB for 1 W @ 1 m when both are driven with 100 W of input power. In this particular example, when driven at 100 W, speaker A produces the same SPL, or loudness as speaker B would produce with 200 W input. Thus, a 3 dB increase in sensitivity of the speaker means that it needs half the amplifier power to achieve a given SPL. This translates into a smaller, less complex power amplifierand often, to reduced overall system cost.

It is typically not possible to combine high efficiency (especially at low frequencies) with compact enclosure size and adequate low frequency response. One can, for the most part, choose only two of the three parameters when designing a speaker system. So, for example, if extended low-frequency performance and small box size are important, one must accept low efficiency.[35] This rule of thumb is sometimes called Hoffman's Iron Law (after J.A. Hoffman, the "H" in KLH).[36] [37]

The full article can be read at: Loudspeaker enclosure - Wikipedia, the free encyclopedia
 
Wont they be decided together as one is a function of the other or vice-versa?

When ever I've attempted to build speakers, I usually had the drivers first, then went on to get my cross over up. The advantage of this approach is that the cross over can be tweeked to sound good with the speaker. I used to start with a basic 10mfd electrolytic cap coupled with the tweeter and improve from that point. Good old days!!
 
Wont they be decided together as one is a function of the other or vice-versa?

Hair most designers have a vast variety of drivers either in the closet or that they can order. A designer is usually given a brief (most often that includes a budget) or set him/herself a brief.

With the smaller brands (like Tidal, Marten, Gradient, Hansen, Kaiser, Gemme Audio, etc..) designers often get enamoured with a certain type fo driver. I knew one desifgner for example who for a while was in love with the B&G Neo 3, Neo 10, drivers and would design his speakers around these.

With the larger brands like Tannoy, KEF, B&W, etc.. designers are given a brief by management for example we want a 6" 2 way that can sit against a wall on a bookshelf for under $100 per pair (not difficult to achieve given the OEM prices for most drivers).

When ever I've attempted to build speakers, I usually had the drivers first, then went on to get my cross over up.

I dont follow this philosophy. I have not built or designed speakers for many years but when I did...this is what I did.

1. Analysed room. How big a speaker it can accomodate. Can I integrated bass sections into coffee tables etc... can I locate speakers 2m from walls (in which I would go OB).

2. Considered budget and electronics being used.

3. Then chose drivers to match.

Since I built only for myself or close family this was easy.
 
I dont follow this philosophy. I have not built or designed speakers for many years but when I did...this is what I did.

1. Analysed room. How big a speaker it can accomodate. Can I integrated bass sections into coffee tables etc... can I locate speakers 2m from walls (in which I would go OB).

2. Considered budget and electronics being used.

3. Then chose drivers to match.

Since I built only for myself or close family this was easy.

That's exactly should be mantra for DIYers. this is the advantage for not choosing manufactured speakers as they are quite generalised. not that generalised speakers do not work, correct DIY perform better. Afterall it is custom built, like a Rolls Royce.
 
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