Paul Carmondi's ZX Spectrum - First Build (pics)

[zxgravediggerxz]

Originally Posted by a.wayne

Thats pretty low for good image height, 39-44 is about optimum , unless you are practically sitting on the floor..



OK ...



Nothing to do with performance , Maybe their girlfriends don't like it either .....

Originally Posted by DrDyna

Nah, it won't.......

I wouldn't go too crazy on pricey cables. Something like this.......

Cool, thanks for the info guys. I'll use the 12AWG OFC cables that I have than.

Only thing that I'm concerned is the damping inside the speaker, not sure how that will sound or how it will affect sound

[zxgravediggerxz]

Finally I was able to finish ZX Spectrums this Monday! Wiring them up took all day!!!

Here are the pics!

They will stay in unpainted DIY condition until spring when the weather gets warmer and I can spray in daylight and not freeze hehe.

The soldering on the speaker terminals is a bit flaky but I will have to desolder eventually to paint and finish the exterior.



15Degree chamfer





bottom plate stand




crossover wiring


before shrinking...... I use a fireplace/grill lighter to shrink the tube lol


binding posts


baseplate chamfered 45deg


finally they are complete!!!! Very DIY look at the moment tho hehe






my setup







So far they are 50 hours into burn in period.... how much longer? I say 75 is good hehe, so tomorrow night I'll turn them up a bit, right now they are running at medium listening level.


Listening impressions: I am comparing them to my Energy Take classics that are sitting on the wall paired with the energy take sub and I must tell that the bass coming out of the M6a drivers is awesome! I definitely don't need a sub for stereo listening... I have the sub crossed at 40Hz for movies and I watched a few already and I must say I am impressed!

Now I am no expert but my energy takes sit pretty high up on the wall and I must admit they sound amazing and detailed, the Spectrums are pretty different tho I think, they sit much lower and are about 3-4ft closer together so my sound stage seems to have shrunk a bit..... but it is still there. With the takes on certain CD's (Roxy's Avalon HDCD) I used to get this immersive sensation but it is less with the Spectrums as far as I can tell now (possibly due to being closer together and lower to the ground).
I tilted the ZXs upward with a 15degree angle and things improved but I still feel less.

I think that the ZXs have a very flat response so far but I find them very detailed at times. I think I can hear more detail but not the detail I'm used to.... kind of wierd hehe.

I am afraid that there might be too much bass tho.... I seriously do not need to even touch the sub. It's not boomy, at least I don't think so. Maybe in the coming week or so after they are properly burned in I will see how tight it gets.

I think Paul Carmody is right that the Neo3's are a bit "darker" and flatter and therefore it makes me think that I dont get that spatial feel because there are no harmonics or coloration to exagerrate the sound.... idk take my words with a spoon of salt.

They do sound pretty damn good so far!!! Considering only 50hr burn in time and listening in the beginning. They are very smooth and easy to listen to!!!!! They feel very light!
For example there is a song where some jazz bass string instument is playing (yes i dont know it lol) and he strumms and taps the instrument's wood and my Energy Takes made my eyes twitch and heart pop as if startled a bit... but that is not present with the ZXs.... is that good? I think so, I guess they are less fatiguing



Anyways, I said you should take my word with a spoon of salt but I will write more next week as they are properly burned in and I get to audition more of my CD's and turn up those puppies and let them breathe more, I have a feeling that the bass will tighten up and the sound stage will open up more as the drivers get more burned in


p.s.
And thank to Paul Carmody for putting up his designs online for DIYers like me. I definitely learned a lot from this first build and I cant wait to make my own design in the near future.

[Lojzek]

Originally Posted by Undefinition

Whoah, I'm late to the party. Anyway, it's me, Paul Carmody. !

Hi Paul,

your ZX Spectrum project looks interesting and I believe it will make happy
many diyers. Just wanted to ask you if there was any particular reason to
use 18 awg air core inductor for the 3 mH.

IMO its dc resistance at 1 ohm is unnecessary high. I am aware people are
somewhat scared of using ferrite cored inductors, no matter how irrational
this fear in our case may be, but it could have been an air cored 15 awg.

Thanks !

[Lojzek]

Originally Posted by zxgravediggerxz

Finally I was able to finish ZX Spectrums this Monday!
Wiring them up took all day!!! Here are the pics!

Hi,

There is one thing you can do to improve improve ZX Spectrum
and that is damping the inner of the box. No matter you glued the
wavy stuff on the walls, it still is not enough to suppress the standing
waves. This you can see on impedance graph at 180 Hz on the project
website.

[zxgravediggerxz]

Originally Posted by Lojzek

Hi Paul,

your ZX Spectrum project looks interesting and I believe it will make happy
many diyers. Just wanted to ask you if there was any particular reason to
use 18 awg air core inductor for the 3 mH.

IMO its dc resistance at 1 ohm is unnecessary high. I am aware people are
somewhat scared of using ferrite cored inductors, no matter how irrational
this fear in our case may be, but it could have been an air cored 15 awg.

Thanks !

Hmmmm.... I think the price of a lower gauge inductor could have played a role in that... when I was looking at the components I wanted to use a bigger gause but i quickly realized that the price doubled/tripled lol

Technically speaking..... yes the lower the resistance the better...... sound wise I am not sure how big it would affect it.

Originally Posted by Lojzek

Hi,

There is one thing you can do to improve improve ZX Spectrum
and that is damping the inner of the box. No matter you glued the
wavy stuff on the walls, it still is not enough to suppress the standing
waves. This you can see on impedance graph at 180 Hz on the project
website.

I think when I take the speakers out to be painted I will fill them with Acousta-Stuf
What do you recommend?

Btw... today I opened the valves on the Receiver amp and..... WOW these speakers are literally getting better by the minute. Had my friend over and they seriously sounded better than they did yesterday! I did have them running at medium volume for 12h straight (around 60hr burn in already). The mids and high are amazing, you can hear a pin drop and the bass strong! I think I need a tiny bit more dampening and fill the bottom 1/3 of the box with Acousta-Stuff next time and it will be perfect. It seriously outguns my sub lol

These are some seriously good and natural sounding speakers!

[Lojzek]

Originally Posted by zxgravediggerxz

What do you recommend?

Check upholstery supplies for polyester wadding.

[mace1337]

I just wanted to say I have the same hifi cabinet from Ikea, and it has the same sagging problem.

[Lojzek]

Originally Posted by mace1337

I just wanted to say I have the same hifi cabinet from Ikea, and it has the same sagging problem.

You better make appropriate modifications.

[mace1337]

Don't worry, I already have.

[Lojzek]

Originally Posted by zxgravediggerxz

Hmmmm.... I think the price of a lower gauge inductor could have played a role in that... when I was looking at the components I wanted to use a bigger gause but i quickly realized that the price doubled/tripled lol

IMO for less money you'd be better off with this one :

3.0mH 18 AWG I Core Inductor 266-558

If you think cored inductors were somehow lesser of a choice, check the
big inductor Dynaudio used in top of the line Xover. It's a ferrite one. I think
these guys know a little bit more than average audiophile diyers.