My 3-way OB new project

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#61
Don't tell the wife!!!

Seriously, D
I've built plenty of speakers before, but these will be the first that I think justify really good quality parts.
When you consider that the P-13s are $98- each, and the tweeter is $65-, then this time I should not try and save a couple of dollars:
 
#64
It has been suggested MOX type can sound gritty or harsh. I have moved from white coffin wirewound to MOX and not had problems (nor real gains). In a good set of speakers I've moved from MOX to Kiwame (both 5W rated) and found the sound just that bit smoother and more correct (perception of lower distortion). A pleasing improvement for hardly any money spent. I've also used the 2w Kiwames in a CD player and liked them.

My project is on the backburner as Christmas presents and other expenses mean I can't afford to buy the rest of the drivers right away!

Simon
 
#65
I really don't want to put any resistance in the signal path before the tweeter and mids, if at all possible; do you think the quality of resistor has any real effects when it is only used in the return pathm as in conjugat circuits like zobels??
I notice Kiwame dont do 10watt resistors, that means doublng up and running pairs in parallel.
 
#69
Moondog55 said:
I remembered this after my post on tweeter modifications, has any one used this technique on the D27 that can offer a comment on SQ of the mod??
Click to expand...

Similar and more going back 30 years... at least till i more or less gave up on domes. We have some particularily nice VIFA D27s (that we used with P13). They can definitely get better than stock. Might be worth revisiting them with the EnABL tools.

dave
 
#70
Moondog55 said:
I really don't want to put any resistance in the signal path before the tweeter and mids, if at all possible;
Click to expand...

To get the "perfect" balance you need small and very carefull adjustments, which is very difficult to obtain with a "hit and miss"...it is possible alright, and said to give clearly better sound without the resistors, but it means you need to know and select your drivers exstremely carefully
You may even need notches to get the right balance, which is a nono to some...I value good balance higher than a few components more or less

As to which resistors and where they are used...I dont believe it matters much, its much more important how you design and do things

I wont suggest that you use 5watt resistors, but I use them a lot with no problems...but they are ordinary wire resistors, they may be more durable than film resistors, but maybe not

Thers a lot of "religion" in components, and from time to time I have even seen a whole nation following such influencial and powerful preachers getting nowhere other than misslead in the wrong direction with no result other than worse sound

Often cheap components are not so messed up
 
#71
Hi Tinitus,
the main raeson I would try and avoid any resistance in the signal path is I hate to waste SPL, having decided on the mids I have been lucky enough to get woofrs that are just a little bit louder so should be OK in that respect.
Your comment about balace in the sound is spot on, if I have to do it I will, but reluctantly.
But that is probably the main reason I have for using this combination of drivers, often used and well documented.
Every sysyem is different and in the end there will be errors, modifications and multiple changes and perhaps even a microphone and a computer involved, but I'll try and get in the ball park before I start buying $50 capacitors and $25-resistors.
The tweeter is actually a little lower in SPL than the two P-13s combined but I don't mind a very slightly reduced treble.

Dave!
with regard to the tweeters what did you do apart from long fibre wool?? I was going to put a felt torus between the bulge and the edge of the faceplare and was thinking of the felt do-nut on top of the pole piece, that tweak or a similiar one I've used a couple of times, in fact once I used a "Dr Scholl" corn pad to advantage.
Question How the heck are you going to paint little dots on that small silk dome?? 😀 😀 😀 :angel:
 
#72
Moondog55 said:
with regard to the tweeters what did you do apart from long fibre wool?? I was going to put a felt torus between the bulge and the edge of the faceplare and was thinking of the felt do-nut on top of the pole piece, that tweak or a similiar one I've used a couple of times, in fact once I used a "Dr Scholl" corn pad to advantage
Click to expand...

Smoothing all inside passages, compensaring with a larger can.

dave
 
#73
More questions on tweeters

I've been doing even more research/reading and i'd like to hear other peoples opinions .
Just re-read the SL's 'Orion " and John K's "NaO" sites.

I have started thinking on the possible need for a rear tweeter.
If I use one do I absolutely need to have exactly the same tweeter or in this instance is something near enough , good enough ??

Given the expense so far it would not be the cost of the tweeter so much as availability, by the time I have the cash D27s may be sold out.
If I use a different tweeter I have made an assumption that I would need to keep to the same silk dome type to maintain a 'coherency of sonic signature'
 
#74
The sound from the rear-tweeter will be reflected before it arrives at your ear. And the reflections will not have a flat frequency response. Which means that the two tweeters will not sound the same to you anyhow, even if you used the same model. Therefore the tweeters need not be matched too exactly.
 
#75
That was my instinctive believe, but all we believe isn't necessarily true, if i have to keep the same XO frequency I think I will need another tweeter with the same low Fs, don't have one on the shelf but I do have a pair of D26AL-05-06.
i also have some good surface mount tweeters but I think Fs on those is too high at 1230Hz.
I /we are moving house soon as our landlady is demolishing to build HD units, and as I've been using the picnic table as a work bench perhaps I should start a new thread on what tools I need to do some better cabinet work, we may be buying a cheap house and the boss says I may be allowed to build a big shed.

I would like these to look good as well as sound good and my woodwork needs all the help it can get
 
#76
The output from a rearward facing tweeter does not affect the formative definition as does a dircetly heard front facing tweeter.

So if a tweeter with a higher resonance is pressed into rear facing service, then a simple parallel connected series notch filter tuned to Fs will not have as deleterious (if noticeable at all) effect as when the same notch would be connected to a forward facing tweeter.

Cheers ..... Graham.
 
#77
In my system I first threw in a wildly different tweeter at the rear. Just connected it in parallel without adjusting the different SPL. That gave me some idea how a backward tweeter would sound in general.

Now with the same type tweeter front and rear it sounds significantly better of course.

With different tweeters I feel that you should look for same general SPL level front and rear (or perhaps a bit less rear) more than for a flat response in the back.
 
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