Pretty Persuasions - InDIY Coax Build Thread

[JavadS]

Javad,
on your XO on the right there are two coils parallelnto each other and fairly close. Why not change the orientation of one to decrease interaction?

Thanks for the comment, yea I can they are about 4" apart and the response of this crossover is identical regardless of how I orient the coils, I did test it. Thanks!

[craigk]

To clarify, they matter if you can hear a difference, and that’s for each person to decide.

Javad, is this how your company builds high performance car parts ? Ben's comments matter because somehow people think that parallel parts in a crossover don't contribute to the sound. Everything in the circuit contributes. Your answer is a little arrogant.

[skatz]

Javad,
on your XO on the right there are two coils parallelnto each other and fairly close. Why not change the orientation of one to decrease interaction?

[cap]

Great thread ! As a wood worker of 35 years I can appreciate the skill.. The knowledge of the x overs and such is always cool

[JavadS]

Got the crossovers finalized and tested today, I ended up tweaking the lpad once I had components soldered in place on the board.



I increased R1 to 2 ohms and R3 to 5.6 to get response back to where I wanted it. Basic layout





And loaded up input and output leads



Woofer spade terminals



Mid push terminals



Binding post input leads





Thanks!
Javad

[JavadS]

This is AC circuitry, and audiophools don't understand that all parts matter.

To clarify, they matter if you can hear a difference, and that’s for each person to decide.

[KEtheredge87]

Be advised- if it's in the circuit, it's in the signal path. This is AC circuitry, and audiophools don't understand that all parts matter.

110 % correct.

Well then... I shan't be labeled an Audiophool! I'll start looking for some AC circuits and speakers "for dummies" references to bring myself up to speed

[craigk]

Be advised- if it's in the circuit, it's in the signal path. This is AC circuitry, and audiophools don't understand that all parts matter.

Later,
Wolf

110 % correct.

[Wolf]

Be advised- if it's in the circuit, it's in the signal path. This is AC circuitry, and audiophools don't understand that all parts matter.

Later,
Wolf

[KEtheredge87]

Hey Keith! Only because it’s a series inline component and not a parallel shunt component, I’m not sure if it makes a difference but they were only $25 and they’re fun to hold and look at =)

Dude... the lightbulb just turned on in my head! I had heard folks talking about components being in the signal path or being a shunt component before, but I hadn't really appreciated the impact that would have! Thanks!

[JavadS]

I see you went for the 90 uF polypropylene cap on the mid section, and used a 150 uF NPE cap for the woofer. Any reason you chose NPE for the woofer besides size / price? I'm still trying to learn when to make the trade-off between component cost and project sound. I know there's loads of opinion posts where folks try to compare NPE to poly caps, so I don't intend to interject one of those discussions here... just curious about your design process. Thanks in advance!

Hey Keith! Only because it’s a series inline component and not a parallel shunt component, I’m not sure if it makes a difference but they were only $25 and they’re fun to hold and look at =)

[KEtheredge87]

Lookin good bud! I need to get to this stage of my own project to allow enough time for the crossover work. I'm getting more excited every week to hear everyone's designs. I'm especially interested to see how the horn loaded compression drivers do, since I've never messed with them before.

I see you went for the 90 uF polypropylene cap on the mid section, and used a 150 uF NPE cap for the woofer. Any reason you chose NPE for the woofer besides size / price? I'm still trying to learn when to make the trade-off between component cost and project sound. I know there's loads of opinion posts where folks try to compare NPE to poly caps, so I don't intend to interject one of those discussions here... just curious about your design process. Thanks in advance!

[JavadS]

Pretty Persuasions crossover update - been a few weeks since I posted about this project but I’ve been working away on the crossover during this time. Things have progressed past the initial model I posted and after testing a number of different slopes, values and alignments, this is where I finalized the design.

Not only did measurements guide this crossover but many hours of listening to my reference music as well. The biggest challenge with this crossover was the sudden mid breakup at 2k, after that response drops and changes abruptly, this is easy to deal with in an active setup (as you may have seen from the active update I did), however with passive it requires much more work than say a good dome tweeter and hifi mid with flat and gentle sloping responses.

Dealing with a horn loaded compression tweeter is always a challenge as well, but all said and done I’m quite pleased with the response and how this speaker sounds currently.

Next step will be to get both speakers up and running in stereo and make any remaining tweaks, typically once things are playing at stereo and everything is installed how it will be in the speaker, a few tweaks to the lpad are usually required

Final response showing individual drivers as well as reverse null response with no smoothing. The reverse null indicates good phase alignment and overall response is quite smooth, there is a small bump at 2600



On axis, 22d and 45d off axis response



Black line is 8” woofer polarity flipped, this transformed the sound of the speaker from thin to warm and full



Overall impedance curve of this crossover, as you can see it dips to 3 ohms in 2 spots, this is a compromise for frequency response and sound, I tested this on a few amps and didn’t have too much trouble driving the speaker, but it’s definitely going to be a little bit more challenging than the average 8 ohm speaker





Schematic, C5 is a tank to roll mid break up off rapidly



Distortion at 85 and 95 dB





Final crossover on my test board



Measurements set up using Omnimic and a 5ms gate



Cutting crossover mounting boards



Starting to lay out components



Thanks!
Javad

[JavadS]

Hey Javad... This question may border on the subjective, but can you help describe "honky" a bit more in this context? I've heard of horn honk before, but never really been able to associate that with a sound. It just makes me think of an old cartoon bicycle horn or something. Thanks! Keith

The issue is probably more related to the Horns boosting the frequency range in the 1 to 4kHz then it is the sound of the horn itself, but yeah that’s the sound you get from a speaker when it’s too hot in that range, it’s Sylmar to the sound of an old clock radio something that doesn’t do you any trouble or anything below 500 Hz. That’s a tough range ain a horn to control as your typical dome tweeter is quite flat thru that range, if you can get it right then you can neutralize a lot of the sound of what people don’t like about tweeter horns in general.

[Wolf]

You're not far off. It adds that honky coloration or 'forced' sound into the lower female register for sure. When I dialed the resistor value down recently on Steve's "Jaws" in the horn's LCR, it was clear that the honk had subsided using Jennifer Warnes.

Later,
Wolf