crossover filter

[SentinelAeon]

Something more on my build. I tested it and i am very disapointed. Not sure what i expected but certanly i wanted it to be better than my previous non calculated speaker. But it isnt. Its not all bad, it still produces decent bass and it is a LOT better than the first few speakers i made which were basicaly tweeters. It still packs a punch and head to head, volume at maximum, it will blow those, i wont mention which, company plastic speakers away. But yeah. The fact that when i cover the port, it makes almost no difference (when in reality it should change F3 from 60 to 100Hz ..) shows that i didnt do something right. It is an acomplishment that i got this bass from enclosure that is probably 2.5 - 3 times smaller than the enclosure of my previous speaker. So that is good. And the material is also dirt cheap. Also good. Also it got me thinking if its possible that the cheap amplifier is simply not sending enough bass into the speakers, i will test that theory with my new amplifier and we will see.

Infact i know i didnt do everything right. I calculated battery volume, battery volume and other things volume and removed them from the equation. But i didnt know i have to remove port volume also, it never crossed my mind, didnt see it mentioned in any video tutorials i saw. Is this the reason i dont get the best results ? I dont know, probably. Right now i am wondering if i can still fix that. Open up theside on which i have port, calculate its volume, put the new enclosure size into equation .. i will probably need to cut the port so it will be shorter due to lower volume.

Also, this PVC really cant handle the bass im putting into it, u can see it rattling madly and only stops when i squize the speaker enclosure. I would be happy of some pointers on what i did wrong and how to correct it.

edit: i need link to where i can buy the pico thing and where i can see their specs.

[LOUT]

It sounds like the music you're playing or maybe your ear's preferance overall favors louder volume at 80hz+ VS somewhat quieter 80hz+ volume with louder deep bass all the way down to 50-60hz.

There are some songs and frequency tests that'll really sound better with a speaker than reaches lower like that, but I feel like a lot of music can sound totally fine with speakers that only reach down to about 65-70hz or maybe even higher, and it's pretty normal for an overall louder speaker to automatically sound "better". So I'm betting your louder Logitec speaker that still reaches "low enough" where you don't easily hear bass has gone missing will tend to sound equal or better for a lot of your music, and I'm guessing this is what's happening.

I have some inexpensive Yamaha 3way bookshelf speakers that my current DIY attempts just couldn't seem to match in volume despite the Yamaha's being 8ohm VS my DIY being 4ohm and using some decently efficient drivers. The Yamaha's aren't in a huge box or anything and their bass still seemed powerful, but I only recently learned enough to realize why my builds couldn't keep up. The Yamaha's DON'T actually dig quite as low and they let their mids+highs play a little louder (less baffle-step correction), so my DIY speakers technically keep up in the low-end and slightly win out in the deeper lows, but the Yamaha's are loud enough and deep enough to sound roughly equal in most music while their slightly louder mids+highs give them an overall louder appearance because that's where a lot of our perception of loudness happens. Frequency sweeps listening suggests these Yamaha's drop pretty sharply below 65-70hz, but I never noticed this until checking for it specifically.
That all said, I'm pretty new to all this and I'm betting the more experience folk could've pointed to the Yamaha's pretty fast while questioning "where's the low end?" after a little listening.

This is where the less deep but more sensitive speakers like the RS125-4/RS125p-4 and the cheaper PC105-4 have an advantage. In 4-5liter or larger boxes they'll only dig down to 65-80hz, but I think you can tune them to be 3db+ louder than the TCP115-4 or 8db+ louder than the TCP115-8.

[Kornbread]

edit: i need link to where i can buy the pico thing and where i can see their specs.

Not a PicoNeo till you build it. It uses one full range Aura ns3-193-8a driver per side https://www.parts-express.com/aura-n...8-ohm--296-258 The black version can be had from Madisound for $13.

[LOUT]

Has anyone compared the PicoNeo's NS3 (older or newer) to the PC68 for fullrange in a small, ported or PR box?

Goes kind of OT
[SPOILER]
I read the NS3's aluminum cone had some less favorable qualities, and I'm assuming its 3inch size means its highs above 6khz fall pretty hard...the PC68's smaller 2.5 size lets it stretch a little higher to around 8khz before the highs start falling badly and it uses a different cone material (though I have no idea if this is a positive or negative in reality). The 68's smaller size also lets it reach a tiny bit deeper in a slightly smaller box while its high-ish sensitivity lets it keep up (at least on paper) on a watt/per basis.
Although they're both about equally sensitive, I'm guessing the NS3's larger size and Xmax can reach louder max volumes. But assuming they're 8ohm drivers being used in a battery-powered wireless portable I think you'd need a 40/[email protected] portable amp along with a larger-than-average battery bank for that to matter.
I think the PC68 is also a little cheaper if you're pinching pennies.

I haven't heard the NS3's but I bought a few of the 8ohm versions of the 68's and found out I like them a lot more than their 3inch sisters (the PC83's that came with a KAB bluetooth amp kit) at least for full-range duty. Despite the 83's flatter response (which looks a lot like the NS3's spec'ed frequency response), I found it a bit too harsh and directional, while the 68's have been a lot of fun with a simple L/(R+C) BSC each in a 2Liter, ported box. [/SPOILER]

[SentinelAeon]

Well i like the speaker but it has a very very bad sensitivity, the daytons are much better in this regard. i might have a problem with my small amps where i need battery life.

[SentinelAeon]

I have a question. QSpeaker program which i like, always seems to give me certain port diameter. I can manualy change its diameter to bigger or smaller and it adjusts length accordingly but if i change enclosure size or resonant frequency, it will change to this "default" port diameter it likes. Its usualy 3.20cm. So my question is, what is special about this 3.2cm diameter ? Do i lose something if instead i have port of 2cm diameter? Because that would be a LOT better for me since port will be shorter and will take less space so there is more space for other components.

[Kornbread]

Not familiar with that software. Maybe if there is an issue with port velocity it automatically steps the port od/id up in size?

[Chris Roemer]

A box size that the NS3 and the PC68-4, as well as the TCP-4 CAN work well enough in is 0.10cf.
The PC can only do 60Hz but can get by w/only a 1"id port (that's 4" long), but it's limited (2mm) Xmax tops it out at only 3w RMS (near 87dB).
The larger 3" & 4" drivers need a 1-1/4" port, but with more Xmax, they can take higher power. The NS3 can take 6w down to 50Hz (at close to 90dB); whereas the TCP (which is the largest AND the greatest Xmax) can handle 30w RMS down to 50Hz, achieving 97dB. They'd both need a vent about 10" long (or PRs) in a 0.10cf box though.

[SentinelAeon]

Since this is a crossover topic i will ask 1 more thing. What kind of inductor i need to cap my woofer ? I know the value but does it needs to be some special kind of inductor or i can just go to ebay and order coil of correct value ?

[Chris Roemer]

A coil has 2 (or 3) "main" specs: its inductance (mH, which generates most of the rolloff characteristics), its DCR (basically the resistance of the wire in the coil - as if it were in a straight run, i.e. NOT coiled) which has an attenuation effect on the driver's output, (and the coil's power rating - before saturation).

A coil w/a DCR of 1.0ohm MIGHT cut a woofer's output by -1dB (for instance). A general ROT is that a series coil's DCR should not exceed 5% of a driver's "nominal" impedance - but...
on the passband for a midrange (for example), if the driver needs padding down anyway, it's cheaper to use a higher DCR coil (higher gauge #) which makes more sense than buying an expensive coil then adding a series resistor in circuit.

Iron cored coils get some of their inductance from being wrapped around a ferrous "core" (could be solid, or laminated "plates", or basically a compressed ferrous "dust"). They're useful for achieving higher Le values at a lower cost and lower DCR (they use smaller gauge wire), but - they tend to saturate at lower power levels than air-core coils.

So, it depends on how you're driver model goes, and how it and your XO design interact w/other drivers (in a multi-way system).

By "cap" your woofer, do you mean to roll off its top end? ?

[Kornbread]

Most of the people here will use an air coil but when sizes start to become large many may switch to a cored inductor mainly because of price and size.

As an example ,,, just some larg'ish random size ... A 7mh air core can range from $20 (18awg, 1.6ohm, 2.5x1") to $50 (15awg, .98ohm, 32.5") while a 7mh cored inductor can be had for $8 (18awg, .61ohm, 1.25x1.75") to $30 (16awg., .297ohm, 4.5x1.6")

[SentinelAeon]

Well i used cheap capacitor to prevent it to play to low and get damaged. Some said that it would be good to also prevent woofer from going to high. Though if this things are more expensive than say 3$ a piece, i will not do it.

[Chris Roemer]

A single (series) "cap" doesn't really do much to protect (roll off) the bottom end of a woofer, reason being that "moving coil" drivers have an impedance peak at their resonant freq. (Fs), which is already on the bottom end - just before rolloff. The Fs peak is typically 2x-4x a tweeter's "nominal" impedance, but woofers can have a peak MANY times nominal - like 10x, or MORE.

[SentinelAeon]

Instead of making a new topic, i will post some questions here. I didn't have the chance to test the stereo mixing and/or button placement yet.

We usualy make a crossover for tweeter and woofer so each cover their own part of frequency graph. I would like to understand what happens if we do not do a proper crossover and woofer/full range both cover certain part of frequency. Just for the sake of simplicity lets asume that woofer and full range both play at same loudness. Meaning both playing vs only 1 playing adds +3dB (~25% increase). I will give you a simple example:

Woofer: covers 50-4000Hz
Full Range: covers 150-18.000Hz

So my question is, what is the effect of this ?

1) Does this mean the frequency at 150-4000Hz that overlap are amplified ?
2) Does this mean that the frequencies at 150-4000Hz cancel eachother and actualy it plays less loud ?
3) How does it affect the quality.

I hope you can help me understand how this works to better understand the reasons behind the crossovers we all use.

[LOUT]

Woofer: covers 50-4000Hz
Full Range: covers 150-18.000Hz

1) Does this mean the frequency at 150-4000Hz that overlap are amplified ?
2) Does this mean that the frequencies at 150-4000Hz cancel eachother and actualy it plays less loud ?
3) How does it affect the quality?

In that 150-4000hz range where both speakers are overlapping, they'll add together (play louder in there) as long as the speakers are playing in-phase with each other OR they'll cancel out (less loud than just one or the other) if they're out-of-phase with each other.
You'll be able to flip a speaker's phase 180degrees by flipping the -/+ terminals around...so this can be a decent way to get them in or out of phase depending on some other things that sadly make it more complicated.
A speaker's phase can be different at different frequencies, two different style speakers can have different phase even at the same frequency, and crossover parts will basically always change the phase compared to playing the speaker without any crossover parts...so there's a decent chance the speakers might add-together to play louder at some frequencies and cancel-out quieter for others within that 150-4000hz overlap.
If you move around or sit in a different place while listening, this can also make it so one speaker might be a little closer and the other a little farther from you compared to other spots you might listen from...this will also change how much they add or cancel, particularly at higher frequencies where they're overlapping (higher frequencies are shorter waves which makes them more sensitive to smaller changes in distance between two speakers playing the same overlapping high notes).

These changes can result in a less smooth/flat frequency response where some notes will be lounder and others softer when they should be more equal....and it can give a strange "phasing" or "comb-filtering" sound (like a kind of sci-fi swooshing) when you move a little and overlapping highs change from adding to cancelling or the other way around in little bits at a time.


It general;
overlapping is a LOT safer for low-ish mids and bass notes, more problematic for high-mids and highs,
it's safer when you're doing it on purpose with two of the same speakers using the same crossover parts (or carefully planned different parts that keep the speakers in-phase during their overlap) which will keep phasing simpler and together where you want it,
it's also safer when you can have the overlapping speakers as close to eachother as possible (often touching edges) this makes moving have less affect on the speak-to-speaker distances,
and it's better when they're above/below each other instead of side-by-side because a sitting or standing person is more likely to move their head side-to-side but not up/down significantly...and a multi-person audience will usually be spread out toward the sides rather than stacked on top of eachother....a top/bottom overlap will keep the same speaker-to-speaker distance as you move side-to-side and only change a small amount when you move between sitting or standing as long as you're a decent distance away.