Loud bluetooth speaker

[SentinelAeon]

The site i am getting my parts from is a bit higher than parts-express (i wont name the site obviously since this is parts-express forum). I would gladly order parts from parts-express, the problem is, i am in europe, so first, shipping costs is about 10 times bigger than shipping on the other site and also, there is an import tax, which will level the prices of both supliers. My suplier is in europe so its cheaper for me that way - parts-express has more speakers though.

DMA70 and DMA58 are of similar price range as CE65W. I checked both of them and many other speakers of that price range in my port calculating app. The problem is, in 1L box i couldnt get decent bass compared to CE65W. They have better sensitivity though so obviously i would love that. CE65W ported in 1L is ok, in 0.5L not ok. That is why i wanted to get into passive radiator thing, to make a ultra small 0.5L speaker. I tried in the past by simply taking a random radiator and adding it. But i will never get a great bass like that, unless i am extremely lucky. I found an interesting site for calculating radiator but it is so simply that i simply cant belive it can be that simple. Simply by weight of the radiator ? It cant be, there are like 20-30 parameters for speaker and many for passive radiator. But i will still add the link to passive radiator calculating site so u can comment:

http://www.mh-audio.nl/Calculators/PassiveRadiator.html

As for crossover ... i have to admit, so far my crossovers were only protecting the tweeter. I never included a coil for the woofer. I simply checked how far the woofer goes ... and capped the tweeter there. It seems to work good for Dayton audio TCP115 ... they go as high as 5.000Hz, but if u look at the graph, they really top at around 2800Hz and then decline. So if the total amp power is 50W and i do it this way, ur saying TCP115 is still drawing 50W ? But where does tweeter get the power then ? Does the amp actualy go over 50W and closer to 60Hz so it powers both woofer and tweeter ? Dont get me wrong, i dont have a problem with TCP115 getting full 50W. It still sounds great at that full power and is perfect for when u want loudness over quality. But if we are speaking purely sound quality, after 90% of volume, u can hear the woofer is really working very hard, its xmax is near limits. Though like i said ... when u r driving this speaker at 100%, u dont care about quality - u r outside with people talking loud and just want as much loudness as possible. Now whether thats good for the speaker, i dont know. I always had trouble understanding base and max handling power. Base is 40W, but what does 80W mean ? Does that mean u can actualy drive the driver at 50W constant, or does that just mean it will handle those split second peaks up to 80W

[LOUT]

Ideally I believe a well-chosen/tuned PassiveRadiator won't sound different than a proper-sized port, but some speakers (as you've probably noticed using your simulator program) prefer longer port-lengths than others to get a nice bass response while a PassiveR is always pretty short regardless of its tuning....so a PR can be a good alternative to a port if the woofer and box-size you're working with would otherwise demand too long of a port and assuming you can find/tune a PR similarly enough to work well.
Mostly, don't expect a PR to sound "better" or create better bass than what you can get with a ported design...think of it more like a different tool for the same job.

Sorry if I'm rambling about stuff you already know, you did mention you want to use a PassiveR because it's going to be a very small sized project...but it also kind of sounded like you might be hoping to use one despite the speaker modelling poorly in an extra-small box and I don't think the PR will be any more helpful for that than a port would be (except for the PR likely taking up less of the box's already limited internal space).

I know basically nothing about PassiveRadiator selection and tuning though, so hopefully someone more knowledgable will also be able to comment.
I think you're probably right about choosing a PR being a bit more complicated though.


About the crossover splitting watts between speakers when you're using just a single capacitor on the tweeter; the woofer does have some natural inductance which can work like there's already a pretty small inductor in series to the woofer. That natural inductance is why some woofers can reach up really high (even if their highs don't sound very good) while other woofers with larger inductance will have highs that slope down in volume quite noticeably. Either way, when you add a tweeter (with a series capacitor protecting it) parallel to that woofer, the tweeter's capacitor will block low frequencies from getting to the tweeter so they'll ALL try to go through the woofer while the woofer's natural inductance (or any more you add with a high-pass section on your crossover) will block highs from going to the woofer. When the woofer is used by itself, those blocked highs are the reason the woofer doesn't play highs very loudly, but when you add the tweeter in parallel with that woofer, now all those highs have an easy place to go so they'll play through the tweeter at full volume unless something else is blocking them or using them.


This is what I'm seeing from VituixCAD for the CE65W and DMA70 in a 1L ported box....and the DMA58 in an 0.25L ported box.
CE65W, 1L ported/PR


DMA70, 1L ported/PR


DMA58, 0.25L ported/PR


CE65W, 1L sealed



To me it looks like the CE65W can reach a little deeper, but its deeper parts are a bit down (particularly compared to its peak around 125hz). To reach convincingly deeper I think the CE65W prefers a box about twice the size.

CE65W, 2L ported/PR


Does this seem to match up with what you're seeing in your sim, or is it pretty different?

[SentinelAeon]

Nice explanation regarding crossover, thank you.

The passive radiator thing, its mostly the observation of small JBL speakers. Take for instance JBL charge 4. I think it is about 0.5L enclosure, something around that. But if you actualy open the speaker, it is amazing. It is basicaly full. If its outside dimensions translate to 0.5L, if u see how much "free" space is there inside, its almost 0. Its full of electronics, wires, plastic frames, etc. I dont think it actualy has even 0.1L inside volume. And what is amazing is that this speaker gets quite decently loud and has a suprising good bass. Now i am not fooling myself, JBL has 100s of great sound engineers who are designing the speakers, have access to any tech they want, etc.

I hope someone can point me in the right direction regarding passive radiators. I have 2 CE65W speakers. I decided, just for the fun of it, to design 2 identical enclosures. 1 will be ported, 1 fill not be ported. I will carefuly compare the bass. Then, when i get some information on passive membranes, i will transform the closed box into a passive radiator one and then compare ported one compared to passive radiator one. It will be somewhere between 0.5L and 1L enclosure. CE65W has really bad sensitivity so i really have to make sure the enclosure is as portable as possible for it to make any sense. Also its almost full range so i dont see a point in adding a tweeter. I wish i could find a speaker of that size that would only go as high as 2000Hz and really put it all into its lows. Then i could add a high sensitivity tweeter and have the best of both worlds: good bass and good sensitivity.

[SentinelAeon]

Does this seem to match up with what you're seeing in your sim, or is it pretty different?

You got multiple functions in 1st graph. Does your program calculate more options regarding what port you choose ? I manualy tune the port frequency and try to get the best graph out. This is what i get. For 4 ohm DMA70 sadly i cant go under 130Hz F3. With 8 version i go to about 85Hz.

[SentinelAeon]

And here is calculated with a different program - winisd, i get same results. CE65 goes deepest, F3 at 66Hz. DMA70 8 ohm goes to 80Hz and has a better looking graph than CE65. DMA70 4 ohm not worth commenting. Also that boost of CE65 at 125Hz or so u mentioned, that worries me. It looks like it will be so loud that you wont hear low frequencies over it.

[Chris Roemer]

something to ponder ...

"F3" isn't always F3 - it depends (IMO).
If you understand BSC (baffle-step compensation), and if you've got a speaker say, on a stand (AWAY from reinforcing boundaries), then (in general) you need to boost the bottom-end (from roughly 1000 Hz down to about 100-200, and below) or the bass won't have the appropriate weight.

If that's the situation w/the red or green? trace (above), then you'd use a largish inductor to "tilt" the response down about -6dB from 100-1kHz, and you'd add -6dB of padding to the tweeter; BUT,
if you're designing with the woofer/box that made the light blue trace, then your BOX will effectively give you +6dB of BSC, although THAT curve looks to peak around 150Hz. The way I look at it, the green curve DOES/WILL have an F3 near 80Hz, but the light blue one will sound like it's dropping off closer to 100Hz than the "65" that you see on the graph. Using THAT woofer/box, you won't need to gain/lose bass (depending on your POV) in the XO, you can design for basically a "flat" line (saving the additional tweeter padding and the cost of a larger coil).

As my own ROT, I'd consider the blue curve and the green curve to (generally) play (strongly enough) "similarly" deep, down to near the 80-85Hz range.
I certainly wouldn't expect (or count on) the blue woofer to sound like it reaches significantly lower than the green one.

I believe that "numbers don't lie", but I do think we can lie to ourselves by (sometimes) misinterpreting them.

[SentinelAeon]

I wont be adding any coils or anything, this is for a ultra cheap speaker. What worries me more about bass is looking at graphs from lout. This speaker is supposed to go as high as 16.000Hz. But his graphs show this speaker is barely usable till 1000Hz. Am i reading it wrong ?

[Chris Roemer]

Those (as ALL) "box modeling" curves really only show the bass rolloff of a driver in a box. The HF portion of the curve most likely is generated the the driver's T/S parms, particularly "Le" (which is the inductance in a voice coil that's PART of how a driver rolls off its high freqs). You can't guess or assume ANYthing by looking at the top part of a box model plot. That's what .frd files and FR plots are for !

[SentinelAeon]

I understand. I started from 0 and am only slowly learning things as i go. First i did without calculations. Then started calculating port, but didnt mind the port dimension and closeness to wall. Now i also do that, make port thats not to small and far enough from wall. I plan to get into other graphs also but i cant take it all at once.

Btw the thing you said about box boost ... +6dB of BSC .. does that show on the graph? Lets say you have a completely flat line of some speakers, you calculate port and enclosure size and still have flat line. Does that mean it will actualy plan flat or will there be boosts at certain frequencies that you simply cannot see only from dB graph for port calculation ?

[LOUT]

I read the whole thing (from new poster JustinBlack). Most of it seemed pretty relavent to small bluetooth speakers and their different qualities as well as being an interesting read in general. Got to the last sentence...."wat"?

[SentinelAeon]

I spoke with tech experter at this site where i am buying speakers. And he recommended me this speaker for that price range: SB acoustics SB16PFC25-4 instead of DC130B-4. It has 3dB lower sensitivity, but has 4.5 xmax instead of 2.5 xmax the dayton has.

https://www.soundimports.eu/en/sb-ac...16pfc25-4.html

This is what he wrote about DC130B-4:

"The sensitivity rating is often based on the frequency response graph and includes loud cone resonances as can be seen here. The pistonic sensitivity is only 88dB/w/m which is still high for a woofer this size but at least reasonable, in contrary to the 92dB/w/m claimed in the specs. The small cone combined with an enclosure that is rather large for such small woofer and low xmax make it not a very good contender. It should be fine in 8L though.
For a 15L enclosure I recommend a woofer like the SB16PFC35-4, a low-ish Qts makes for a good balance between bass extension and sensitivity. The larger membrane combined with an appropriately sized enclosure and the higher Xmax makes it a much more competent woofer. Plus, it is very, very lightweight thanks to the clever basket construction."

[Mayhem13]

People in EU have been using this for decades for your purpose

https://www.parts-express.com/visato...8-ohm--292-548

Probably half the price in EU so if you could get your buddy to go for a pair, build a pentagon enclosure for wide dispersion. Run them in parallel and it will be the loudest cheapest party speaker in existence. The BG20 is also highly regarded for sound quality amongst the fullrange crew

[SentinelAeon]

I found one for about 30€ on some german site, my suplier sadly doesn't have one. Its 8 ohm though, that will be a problem with my amps, cause they will only supply like 20W to the speaker. Its interesting that its a full range speaker, going to 18.000Hz. The only problem though is that a single one in 15L enclosure goes only as low as 79Hz. In 30L enclosure with single speaker i can go down to 62Hz which is just fine. I will keep this speaker in mind for future builds, maybe try to find some different amplifier.

Since we are here i have a question. How do a single full range speaker compare to separate woofer and tweeter ? I am asking because for instance, JBL charge 4 has full range (people say its missing highs though) and i am wondering physics wise, how does it affect the speaker that it has to play super low and super high at the same time ? Do you actualy get better loudness and bass if u use separate woofer and tweeter ?

[SentinelAeon]

I ended up ordering the 8" SB20PFC30-4 speaker. I ran some configurations in winISD. This graphs change a lot depending on what resonant frequency i set. The previous speaker the customer had was TCP115 8 ohm running on 20W. So that means its 6dB less loud than TCP115 4 ohm (Actualy its about 8dB: 3dB from running at half power, 3dB for being 8 ohm vs 4 ohm and about 2dB is simply sensitivity differences between 4 and 8 ohm). Well, the graph says the 8" SB is about 10dB louder than TCP115 4 ohm. So that would mean new speaker will be 18dB louder, which just cant be right, that is huge, so i must have done some calculation wrong.

But anyway speaking purely from what the graph shows, he should be getting quite loud speaker. I also added 2x TCP115 4 ohm configuration since you mentioned it. It is quite loud also, about 3dB less than the 8". But i am assuming single 8" will use less power than 2x TCP115 due to better sensitivity which is good. A single TCP115 has better bass in this 15L enclosure, 2x TCP115 also has a better bass. Which is kind of funny though cause if you look at SPL graph, the SB maintains higher SPL much lower.

Could someone explain this to me so i will better understand it ?

[SentinelAeon]

I read the whole thing (from new poster JustinBlack). Most of it seemed pretty relavent to small bluetooth speakers and their different qualities as well as being an interesting read in general. Got to the last sentence...."wat"?

Just wanted to share with you 2 pics of my newest speaker i made for myself, took it to a photoshoot today