This might be too big- 3 litres sealed (@ 9.5" h x 5.125"w x 4.5" d) add more depth for the binding posts.
Does it hit 50hz? Keep looking.
from the designer post "1,
"Passive Radiators ended up with no weight which resulted in a 56hz tuning frequency, more boosted than I wanted but adding any weight maxed out the excursion that much sooner. I was able to add 15 grams to bring it down to 50 but the passives were straining much sooner, as is the W5 easily over powers 2 5" PR's, really 3 or 4 of these would better keep up with 1 W5."
https://techtalk.parts-express.com/...crofarads-nano-speaker-using-ps95-and-w5-2053
Does it hit 50hz? Keep looking.
from the designer post "1,
"Passive Radiators ended up with no weight which resulted in a 56hz tuning frequency, more boosted than I wanted but adding any weight maxed out the excursion that much sooner. I was able to add 15 grams to bring it down to 50 but the passives were straining much sooner, as is the W5 easily over powers 2 5" PR's, really 3 or 4 of these would better keep up with 1 W5."
https://techtalk.parts-express.com/...crofarads-nano-speaker-using-ps95-and-w5-2053
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Is this what you want. That bass, with better high end?
Can we see them, or get a model number.
I was on eBay looking at empty cabs, and some 2" one's came up. I was quite surprised. Perhaps your Citizen bass would fit, along with a dedicated mid/tops driver. Perhaps that ??9?? people have.
Right now, we are all chasing after a nice flat bass down to 50Hz, but if you are happy with what you have, we should really see what that is. As you say, you can't put numbers to what you are hearing.
If we look at the ever present Wharfdale Diamond, the £100 model 9 is £50 from Richers, and rated from 60Hz. Not the shape you want, but at 145mm wide, the driver misses the edge of the cab by 20mm maybe. It's something you can demo, then rebuild. Alternately some Kef eggs. The Mk1 with the black tweeter is alright. I have some on a desk with a chip amp, and they sound fine without the sub on. The sub was a waste of time tbh. They are nice and getting a lot cheaper this year. Black tweeter though. The silver 'point 1' model was slipped in it's place, and compromises on everything. Gaining a Q series tweeter and loosing half the magnet. While the first one's made hifi home cinema a thing, not just for goodmans. They opened the market with them. It's reference stuff.
hi k'n'h,
someone else said that, i didn't.
if you like we could arrange a deal: you donate 50 $ or more to DIYAUDIO and i will try to answer your questions as good as i can.
it may not be exactly the answers you would like to hear, though. 😉
You can’t be half pregnant. Any time you put a price on something either for you or a cause regardless if it’s $50 or $5,000, you better put a resume in front of it first and put your full reputation on the line, as far as you are an expert on the subject matter, you can go down to the same level as your client and explain things based on their level of intellect not yours, without sending them any links to read, and the answers cannot be too broad.
If you can do that you should not be here, you should be on Fivver or anywhere else charging people for your expertise. If you take the approach you just did, you will ruin your reputation very quickly and will never repair it.
It’s better not to engage at all then do it half ***.
I started with that on purpose to give people my reference, but with all the lateral suggestions that reference go berried and people dismissed that input and we wasted 3-4 pages of useless discussions. If you go back and read all my references you will discover my questions are not as dumb as they look. I used to have a very expensive hobby and went thru mixers, pre-amps, bass guitars, active monitors, so I developed a taste for how things sound or how I like things to sound. I do not know how they work internally, but I do have a taste of how things sound.
Today my sound reference is based on very laid-back non-fatiguing non-colored sound that is ATC sound. Back then I hated ATC, I had a much bigger treated room liked more punch a bit darker sound like Klein + Hummel 3-way active (pre Sennheiser years).
ATC active speakers use some type of 70% Class A and 30% Class B amps in their active models, which contribute to their laid back non-fatiguing sound plus that famous SM75-150S mid driver is the main star, but it can never work in desktop small speaker. ATC passives are also laid back as well so it’s not all in the amp.
Dunlavy is also used in many mastering studios because of their non=aggressive non-fatiguing smooth sound, John was fixated on 6db crossover, closed cabinet and stuffed to the gills. Klein & Hummel that I had was also closed and stuffed to the gills and I think they even had the SM75-150S mid driver in it, I never opened it, it had killer mid range, that’s when ATC was still selling SM75-150S to other manufacturers so some models had it some had something newer.
These are my top three reference and they will never change I auditioned many speakers back then up to 10k, non I liked… Because no one will reinvent the wheel with cone constructing or micro AD/DA digital will never surpass Analog, digital is clean but it’s sterile, I went thru Apogee, Lynx, Digidesgin, RME……not the same, running something via Midas Venice board sounded 5 times better then any of these ADA’s. So DSP is out for now.
I knew from the start I will need to add gain to the bass, 3” drivers cannot roar like a Lion we all get that and 10 mice collectively also cannot roar like a lion either we all know that.
I was simply trying to figure out which options on gain would have less color and less fatigue.
The way I see it, there are only two choices.
Lower everything down to the 50hz db flat level, then raise the overall volume of the speaker until you Passive option was on the table as well.
Active only, add gain to the low end to level it with everything else, this would be much harder I mean more trial and error as far as where exactly to zoom in, is it specific fixed frequency or a range of low frequencies, this will also have some color.
Then on both options the choice is also do you add gain 100% via cross-over / EQ op-amp or do you add maybe 2-3db via main Amp, and the rest via crossover op-amp.
This is why I referenced Avalon U5 early in my thread. That unit has 30db gain by 3db increments, not sure what frequencies it covers. I love that sound of U5, it’s very clean gain, nothing in $3k - $5k price range comes close to that pre-amp as far as no color no warmth no nothing just big head room, very open airy sound.
I need an expert on amps/ EQ / pre-amp more then on actual speaker driver specs.
So I cast a big net to see what answers can I get as far as how can I get to clean non fatiguing sound with some gain on bass based on references I put forward.
But you all went over my references; maybe my questions are simply to complex to answer what part of an op-amp gives its sound characteristics even if we do have the full schematic to look at.
Class A amps are expensive need to be big and will be too hot at such close range, so maybe something can be done via op-amp crossover to get some portion of that clean gain on bass. I do not need 30db of gain, but maybe up to 15db -20db
The cheap speakers I have, I googled them they do not exist, 20 years old, drivers are not made anymore “p3duc” the amp is this one:
https://quasarelectronics.co.uk/Item/3090h-3w-stereo-amplifier-module-ba5406-with-heatsink
By the looks of it since I have tone controls it’s most likely up 28db gain on bass not sure f there is a shelving filter limit on that 28db.
When I crank the speaker volume all the way and my macbook to it’s max, no distortion, but I can see my the cone it’s at it’s max, any more db something will happen to it. Amp says it’s up to 85db, I’m just guessing that it’s playing somewhere near 80 - 85 db max.
Bass boost at 70% is where you can hear kick drums and bass guitar nicely as far as even level with high end frequencies, Treble is to it’s max, but still not clean too muddy, well it’s all muddy, too much color too much warmth.
The irony of it all, it’s perfect size driver, exactly 76mm (frame) paper cone, hard to measure X-max, I’d say under 3mm for sure.
I hooked up another 4ohm slightly bigger 89mm driver full range as well to see if it’s the amp that giving it color but it’s rated 10 Watts, it has more high end more balanced overall sound but it’s volume is so low I can’t bring it up to figure out which is which, the paper cone is thicker so I suspect its eating all the mid and low mid frequencies with that thickness.
In any case the driver is not the issue here, I can addition many drivers, the key is to sort out the active system as far as less color behind the drivers.
Attachments
Not knowing of any drivers that would fit the bill but with those physical restrictions I would think of a small "line array".
Sort of MMMTM or MMMMT. Could be 5(7) identical drivers with 4 low-passed and the middle one high-passed (1st order?).
Did something similar (for fun) with cheap Visaton FRS8M I had lying around (for a cheap test speaker) and was surprised by the results although it was far from refined.
If I´d make a proper speaker out of it, I´d choose a fullrange that has very good treble for the "tweeter", maybe FF85K or a small Mark Audio.
The midwoofers should be chosen towards fitting that volume and with EQ + healthy xmax being able to support lower frequencies.
Only obstacle being the "tweeter" would need its own volume so the cone doesn´t get pushed around by the others and the still limited volume for the other drivers.
Just an idea.
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I thought about an array as well, with 3 or 4 2" drivers, the problem is I do not know the math on it, meaning if cone size of 2 x3" is the same as 2" x 3. Aesthetically MTM looks the best at such a close range, plus I have no idea how can 3 or 4 drivers work in synchrony without delays in a closed cabinet. I suspect one could push the air and it would pull the other one out, the more drivers in parallel the more chance they will play out of synth and more chance of mud in the middle.
Plus having multiple drivers play the full mid range is also unknown to me how muddy it will be so it becomes more difficult choice……. do I use two for low end two for mid, or three for low end one for mid....too complex on crossover and amp configuration. I mean requires more trial and error. Plus the choice on 2” - 3" drivers with 16 or 32 ohm rating is very limited.
Cheers
well, my proposal was not entirely serious. thus the "😉"
your specifications, if I remember correctly:
- two 3" drivers
- closed box
- no high excursion drivers
- bass extended down to 50 Hz via shelf filter
assuming two 3 inch drivers in closed box, 2pi radiation (box standing on a table or near the back wall which increases bass output) this results in maximum SPL at 50 Hz:
with 0,5 mm excursion: about 65 dB
with 1,5 mm excursion: about 76 dB
with 5 mm excursion: about 86 dB
furthermore assuming a music crest factor of 12 dB and avoiding high distorsion at peaks you can listen to music containing bass down to 50 Hz at an average level of:
with 0,5 mm excursion: about 53 dB
with 1,5 mm excursion: about 64 dB
with 5 mm excursion: about 74 dB
possible ways of increasing sound level:
- less bass extension (e.g. bass rolloff below 100 Hz instead of 50 Hz gives +12 dB)
- increasing diaphragm surface by installing additional drivers or bigger drivers (doubling diaphragm surface provides +6dB)
- increasing max. driver excursion (doubling excursion provides +6 dB)
- using bass reflex, passive radiator, transmission line or horn enclosure (consider increased box size!)
- (edited): using a limiter/compressor to reduce (bass) peaks = reducing crest factor.
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Where did you come up with the concept of Crest Factor?
I’ve been asking similar questions with few tech support people at different companies that sell drivers, the response I got is a bit different from yours.
Which is:
Response curves when shown on a graph without smoothing will be very jagged. We use some smoothing to make the graph easier to read and to average the results since our ears hear the sound as a range not a single precise tone among all the others. The sensitivity rating is not based on those spikes so I would not really use Crest Factor type as any kind of guide.
I’m not trying to play one against another who is right who is wrong, I’m trying to find a way where multiple people provide input and most of it matches then I know it’s the most effective solution, if the input varies greatly then it’s a bigger gamble in which solution to pursue.
The drivers I'm looking at, one is X-max of 2.4mm one is much bigger at 3.8mm so might not be a tight sound.
What dbs can I expect from these two drivers in the 50 -100hz range with a closed and stuffed cabinet, no passive radiators an no ports, not sure how you guys calculate stuffing, do you double the cabinet size?
Cheers.
A pair of Kartesian Sub120_vHPs will provide over 90 dB with 100 watts (hitting xmax). Not cheap - $95 a piece - but a lot cheaper than the Purifi PTT4.0.
I did not come up.
it's not related to loudspeakers or the response curves.
it is a value used in mastering of music.
it describes the difference between average level and peak levels.
for example and quite simplified kick drum beats may be 12 dB above the rest of the music.
you may accept some compression or distorsion of these kicks but it can sound quite annoying.
do an internet search if you want to know more.
for a closed box the maximum low end output only depends on air displacement, independent from stuffing or box volume.
for an additional octave of lower extension you need 4X the air volume (+12 dB).
for two 3" drivers with 2,4 mm X max this means:
max SPL @ 100 Hz: 92 dB
max SPL @ 50 Hz: 80 dB
Ok, we're back to square one then, my target was 50hz at 80db, I can probably live with maybe even 75db, does that mean I can get there without boosting the bass by 12db, if we take out your Crest Factor. As I understand it, Crest Factor is not an issue here, I do not do any mixing or mastering, music is already mastered so I can't see where all of a sudden something in a fully mastered song will jump out by 12db more then the rest of the sound. Sure some songs are louder then others but if we set the main volume to cap everything at 80db, then nothing will get thru past that limit. In fact with MP3/ Youtube logic would dictate it's even more compressed with less peaks and valleys.
if that is your target - perfect, your are fine!
that will depend on the parameters of you loudspeaker driver and the enclosure volume.
give me your driver TS parameters and the planned box volume and i can tell you how much you need to boost the bass for even response down to 50 Hz.
well, if you still don't believe me with all my efforts let's just leave it there.
build the loudspeakers and let us know if you like them!
I did not say I don't believe you, I'm simply trying to understand it and figure out where do I make the sacrifice, on my overall speaker volume based on least amount of gain on low end or use a driver with more x-max and suffer with loud but poor low end.
Lets try these two in priority sequence:
1) https://eminence.com/products/alpha_3_8#specifications
2) https://products.peerless-audio.com/transducer/193
Sealed cabinet (stuffed), volume do not care, width around 3.5" depth in the 4" -5" max, height - I leave it up to you to find the optimal volume to get the best of the low end.
Question about volume, with MTM or any array type design, is it better to have a separate chamber for each driver, that's with a sealed stuffed approach?
Cheers.
well, this sounded very much so:
don't be suspicious just because people tell you something you don't like to hear.
ok, so sealed cabinet for two drivers with (exterior) dimensions 3,5" * 5" * 12" and 1/2" wood: around 1,7 liters.
increasing the volume helps, but will need much bigger size for relevant change.
eminence alpha 3-8 has a smooth response and rolls off below 200 Hz, you will have to boost to a maximum of around 20 dB at 50 Hz.
peerless TC9FD18-08 will have a more peaky response around resonance frequency because of high Qts and will need a boost to a max. ~ 24 dB at 50 Hz (and some further equalization).
very rough graphs below:
- response with needed equalization.
- max SPL following the data of spec sheet (Xmax and 30 W max. power)
Attachments
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Are we boosting both by 20db? What if this was tri-amped, are we boosting each driver by 10db? More importantly is x-max the main limitation? I'm looking at Alpha 3-8, it's shorter x-max then Peerless but needs less boost, how is that possible if X-max is teh king of all measures on how much air you can push out?
For example they have a 32 ohm version:
https://eminence.com/collections/em...n-standard-series-speaker/products/alpha_3_32
So if we had more power, can we push it further with less gain to get to 80db?
For example they have a 32 ohm version:
https://eminence.com/collections/em...n-standard-series-speaker/products/alpha_3_32
So if we had more power, can we push it further with less gain to get to 80db?
yes, more or less.
no, total output must be boosted by 20 dB (10 * voltage and 100 * power);
it makes no difference how many amplifiers you boost. the ratio is always the same.
you can see it on my graphs: red line is X-max limit; black line is power limit (thermal limit for voice coil).
it differs for the drivers:
eminence is more efficient, so will produce more SPL with 1 W.
but it will also reach x-max with less power, because it travels more with same power and it also has less x-max.
eminence drivers will need less power but will sooner reach the x-max limit.
it's like having a car with a powerful engine but weak tires. it will accelerate quick, but the max. speed is limited by tires.
the other car with weak engine and good tires will accelerate slowly but may reach a higher V max.
ok, not the best comparison...
32 ohm version will not change much.
that only requires an amp with more output voltage (and less current).
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There is no humor here and never was. It was disguised as humor.
Business 101, balls over brains. Fortune favors the brave not the smart.
If you were very confident that the advice given on this forum for others is always sound advice by every single memeber, you would have mandatory pricing on membership.
I do not know of any successful business where the business model is, take my product if you like it pay me if you don’t like it don’t pay me. No reputation on the line that means no success as far as steady revenue stream……. again Business 101.
It goes back to balls not brains. If you have the balls to put your reputation on the line and charge people for mandatory membership, very quickly you will find out how much brain is behind the whole operation and how do customers value it.
If no balls, then you never risk your reputation and you come at them with the approach you just took of guilt or pity.
When I ask very dumb questions, I put my reputation on the line in looking like an idiot in front of everybody, but in return I get some knowledge back. The price of that is equal, to pay people and publicly look like an idiot is broken business model it's no longer an equal trade off. If it was done privately then the price might be worth it depending on the structure of the deal.
Cheers.