Overnight Sensations Build Questions

[KnightsOfNi]

My family is admiring my Statement build and asking me to build them something.
I have been looking for simple low cost designs that I can try for them.
The Overnight Sensation looks like a great simple build for this.
I am looking up the crossover parts at Solen here in Canada and I can't get some of the components exactly on, does it matter?
1. I can get 6.2 ohm resistor not 6.0 ohm
2. I can get 0.36 mh dcr 0.40 ohm inductor, not 0.35 mh dcr 0.40 ohms
Does it matter? Or should I get the right one.
Parts Express is great but they are very expensive for shipping to Canada.
Thanks for your help
Knights

[Undefinition]

Those values are definitely close enough. You'll be good to go.

[Bent]

two 3 ohm resistors in parallel will give you 6.0 ohms
and you could unwind a couple turns on the inductors - that would put you in the ballpark.

However, I tried unwinding a couple of inductors, even with my sencore inductance meter I still found it much like trying to heard cats. Those inductors don't unwind very neatly.

[BOBinGA]

Two 3 ohm resistors in SERIES will give you 6.0 ohms. (But 6.2 is so close you will never tell the difference.)
I wouldn't touch a .36 mH inductor. It's so close that unwinding even one turn will drop it below the specified .35 mh. Besides, in my experience, inductors tend to actually measure just under their specified value, so don't touch it. It will work fine as is.

-Bob

[Bent]

Oh man,
I can't believe I said that - my face is red with embarrassment.

putting them in parallel could have been disastrous to the driver depending on how they were configured - I'm very glad you interjected.

As an excuse, I'm on cold medication - Vodka and Kahlua, served warm.

[BOBinGA]

No worries, Bent. I was pretty sure you had simply "misspoke". Someone like you that has been here seven years and 1500 posts would certainly know the difference. I just wanted to make sure the the OP didn't get confused.

-Bob

[KnightsOfNi]

Thanks for your replies!
That first one came in really fast.
I thought about getting 2, 3 ohms resistors in series but I hoped it would not be necessary.
Thanks for the replies.

Also if I may a couple of design questions;
1. Does the 6" port length include the thickness of the back panel?
2. Is the baffle/ back removable just for crossover install, is it necessary?
3. I am probably going to use 3/4" MDF, maintaining the same Inside dimension and use a 3/4" round over on the sides, does this sound ok?
Regards
Knights

[1Michael]

1. No. The port length is measured between, the halfway point of the flares.

[KnightsOfNi]

Hi thanks for your answer.
The port calls for SCH 40 PVC pipe, so I assume the outside flare is a round over in the back panel, is the inside flared also?
Thanks
Knights

[Undefinition]

Also if I may a couple of design questions;
1. Does the 6" port length include the thickness of the back panel?
2. Is the baffle/ back removable just for crossover install, is it necessary?
3. I am probably going to use 3/4" MDF, maintaining the same Inside dimension and use a 3/4" round over on the sides, does this sound ok?

1. Actually, on mine, there is no flare. The 6" length includes the thickness of the panel.
2. The removable front or back baffle is completely optional. I just made the crossover on a board that was small enough to fit through the woofer hole.
3. Yes, 3/4" MDF is fine. The internal volume has to stay the same, and the baffle dimensions should stay the same (thus, depth will increase). I know there are plans of it in 3/4" floating around somewhere on the internets.

[KnightsOfNi]

This looks like a cool design and I would like to give it a try, so I just ordered all the parts!
Should be a fun build over the holidays, it is also nice to get away from the Mini Statements for a bit.
I am currently veneering 1 and clear coating the other and it is not my favorite part of the project! It is going well though.

I have my plan formulating on how I am going to build them but I have another question.
Was there any round over applied to the baffle when it was voiced?
Therefore should I be rounding any of the edges?
I am planning to, but I wanted to check.

Thanks again
Knights

[Undefinition]

I have my plan formulating on how I am going to build them but I have another question.
Was there any round over applied to the baffle when it was voiced?
Therefore should I be rounding any of the edges?
I am planning to, but I wanted to check.

Mine have a roundover on them. 1/2" I think, which is not enough to make any audible difference. It was just a cosmetic decision.

[Matt ITD]

Hi All,

Just had a question regarding placement of the ports.

Do you recommend placing them in a certain spot e.g. front, back, distances apart etc?

Also is the recommended port dimensions 40 millimeters (outside diameter) X 6 inches long?

Many Thanks

Matt

[peepaj]

I put mine on the back, behind the tweeter. Port dia. is 1.25 inches or 31.75mm. You can also check Paul Carmody website at http://sites.google.com/site/undefin...ightsensations

[Undefinition]

The general rule of thumb I've used for port placement that has always been good to me, is that you can place a port anywhere on a speaker, as long as the port exits are at least 1/2 the diameter away from any other wall or surface.
Also, to date, I have not seen or heard any conclusive evidence that mounting a port on the front, rear, or bottom produces any difference in sound quality.

[Matt ITD]

Hi All,

Just wondering if someone can take a look at my drawing of the overnight sensations? I have placed the port on the front and in doing so moved the tweeter over to the right a little more than the original. Is this detrimental? Is the offset to great?

Many Thanks

[peepaj]

Not sure about moving the tweeter, but Soundslike on the PE site did his without moving the tweeter. http://techtalk.parts-express.com/sh...d.php?t=223751

[BeerParty]

Hi All,

Just wondering if someone can take a look at my drawing of the overnight sensations? I have placed the port on the front and in doing so moved the tweeter over to the right a little more than the original. Is this detrimental? Is the offset to great?

Many Thanks

Don't move the tweeter location. The driver locations on the front baffle are important for the crossover design (if you move the tweeter to a different location, you have to design a new crossover).

[Matt ITD]

Thanks for the advice. I wont move it then. Thanks also for the link peepaj.

[Undefinition]

Don't move the tweeter location. The driver locations on the front baffle are important for the crossover design (if you move the tweeter to a different location, you have to design a new crossover).

That's a bit of an overstatement. Placement on baffle can and will affect the Frequency Response of a driver, however the amount by which it is affected (and the frequencies affected) can be pretty minimal, depending on where you move it and by how much.

My personal experience has been that the whole centering vs. offset tweeter issue tends to produce artifacts that are much easier to measure than hear.

[BeerParty]

That's a bit of an overstatement. Placement on baffle can and will affect the Frequency Response of a driver, however the amount by which it is affected (and the frequencies affected) can be pretty minimal, depending on where you move it and by how much.

My personal experience has been that the whole centering vs. offset tweeter issue tends to produce artifacts that are much easier to measure than hear.

It is your design Paul so you would know whether the OP's change would have an impact or not. If you think it is OK I don't even have the knowledge to argue the point, really. ops:

That said, I feel that us amateur DIY builders can mess things up enough by accident without deliberately introducing changes that are known to change the performance of the speakers. So when someone asks this question (and it gets asked a lot), I tend to err on the side of caution and recommend against it.

[Matt ITD]

OK i have gone and done it!

I have ordered the parts from parts express for the overnight sensation. I am going to build 2 pairs of the MTM version and 1 pair of the MT version. I am actually very excited about this. I have been busy modeling them and working out my cutting plan. Could someone please take a look at my drawing and tell me if I have anything noticeably wrong. I have used Paul's website as the guide.

PS sorry its in metric.

Thanks

Matt

[Matt ITD]

Hi All,

I had a question I hope someone can help me with.

I am in the middle of my build, OS MT and OS MTM.

My question is regarding the port diameter and length.

I can only find 30mm (internal diameter) pipe. Your design called for 32mm. Can I use the 30mm without any noticeable changes? If I do use the 30mm what would the possible changes be?

Thanks Heaps

Matt

[Undefinition]

I can only find 30mm (internal diameter) pipe. Your design called for 32mm. Can I use the 30mm without any noticeable changes? If I do use the 30mm what would the possible changes be?

No problem. A pipe with 30mm inside diameter needs to be 137mm long.

[Matt ITD]

Thanks Paul. I have completed the MT versions and yet to do the crossovers for the MTM versions. I added a small hand full (fluffed) of acousta stuff, checked the crossovers (made sure I reversed the polarity on the tweeter) and think I did every thing else as per the design. I have been listening to them for about a day now and I have to say I don't think I have it right. They sound muffled, muddy there is an absence of mid range. They are not crisp like I was expecting, in fact my Logitech computer speakers (which these were to replace) sound much better. Please tell me I have overlooked something as I have yet listen to 4 MTM versions and I am honestly not looking forward to it. Any help would be appreciated!

Matt

[Undefinition]

Yeah, something's definitely not right. Usually when people run across these sorts of problems with builds, they'll post photos of their crossover. That might help us. My first guess is that something's wrong with the tweeter filter.

[peepaj]

Matt, do both speakers sound the same? did you cover the walls of the cabs?
Although we always check the connections it is very common to still wire them in reverse. You could try swapping the tweeter wires around.

[Matt ITD]

Hi All,

Thanks for your help with my question regarding the MTM version. I put this project on hold because I just wasn’t achieving the sound quality I thought I would be getting. I picked it up again and in 5mins had worked out my errors and with some corrections and soldering was soon listening to great sounding music. In fact to be honest a little pee came out when i first pushed play and I heard good sound :T . So thanks all, and a big thank you to Paul for the design.

Matt

[Matt ITD]

Now I have the overnight sensations under my belt (finally) I was thinking of tackling another project. Ultimately I would like statements but think I need another step before I tackle the big girls. I was thinking of the Nat P's. Would this be a suitable second build and am I likely to hear a difference in sound reproduction to the sensations?

[BeerParty]

Now I have the overnight sensations under my belt (finally) I was thinking of tackling another project. Ultimately I would like statements but think I need another step before I tackle the big girls. I was thinking of the Nat P's. Would this be a suitable second build and am I likely to hear a difference in sound reproduction to the sensations?

What is it about the Statements that has you worried?

[Matt ITD]

I would like to improve my cabinet skills a little more. I would also like to build another slightly less complicated crossover and improve my crossover layouts before tackling the statements. In short I think I would just like to get some more experience. Am I being to cautious?

[BeerParty]

I would like to improve my cabinet skills a little more. I would also like to build another slightly less complicated crossover and improve my crossover layouts before tackling the statements. In short I think I would just like to get some more experience. Am I being to cautious?

OK, I was thinking it might have been the size of the Statements that put you off. If that was the case I would have suggested that you try building the Statement Monitors or the Minis. Then if you still wanted to build the full sized Statements afterwards you could reuse the tweeter and mid-range driver and most of the crossover components. That was my plan when I build my Statement Monitors, then I heard them and couldn't imagine tearing them apart.

Based on what you said above you have a lot of choices; if it were me I would look through the Completed Speaker Design thread and the Mission Accomplished sub-forum and pick something. I have never heard the Nat P's so I can't say how they would differ from the OSes, but I know a lot of people are very happy with the Nat P's.

Are you being too cautious? I think the only way to be too cautious in this hobby is to not do anything.

[Matt ITD]

Thanks Chris, Size is definitely not a problem! I did browse through the Completed speaker design thread and thought the Nat P's would be good. I have read a lot about them and from what I can tell, all who have built them have been super happy with them. Can anyone who has built them please share your thoughts. Many Thanks.

As a side note, again I am loving the OS