Newbie here, with some primitive questions.
Do not know too much on SPL, crossovers do not have any tools to measure stuff nor know how. Would need to pay someone most likely to design something and guide me thru the process.
Scenario, a pair of computer speakers (no 2.1), listening range is only 2-3 feet, do not care how they sound past 3 feet. Closed cabinet and stuffed, do not like ported speakers.
Two 3” drivers and a tweeter, could be 2.5 or 3-way, could be passive bi / tri-amped, or active bi/tri-amped not sure yet, open to all scenarios.
Most 3” drivers in the 84 - 88db SPL range roll-off around 120 – 100hz and at 50hz they are around 72db – 73db. That’s if the specs are not inflated. Was told that the specs at 1 meter are based on low voltage and do not translate to real life…not sure what it means.
If I want it to be flat from 50hz to 2000khz or 4000khz at around 80 db then cross with a tweeter, what is the solution without adding any gain via tone control to that 50hz-120hz range or any color to the sound?
Running two 3” in parallel would add 6db so I’m already at my 79db - 80db from 50hz to 120hz, but after that if I want to run only one 3” as mid range up to the tweeter.
What type of filter or EQ or solution is needed to run one 3” from 50 to 100hz at it’s full SPL, then cut it off either 6 or 12 db slope, then past that 100hz mark somehow the second driver drops by either 4 or 8db depending on the tweeter I choose not sure on the slope to avoid too much mud in the middle.
Can this be solved without DSP? And how efficient will it be without any peaks or too much mud in the low mid to mid section?
I can pick tweeter with low FS to match the slope of my 100hz so if its first order at 100hz I can probably push the mid range to 4000khz cross over.
In general if it’s off by 1,2,3, 4 dbs…. how much can an average human hear these 1-3 db peaks and valleys at such a close range of 1-2 feet, so if this problem is not solvable without adding gain or adding too much color with too much EQ adn have to live with minimal peaks and valleys?
Cheers.
Do not know too much on SPL, crossovers do not have any tools to measure stuff nor know how. Would need to pay someone most likely to design something and guide me thru the process.
Scenario, a pair of computer speakers (no 2.1), listening range is only 2-3 feet, do not care how they sound past 3 feet. Closed cabinet and stuffed, do not like ported speakers.
Two 3” drivers and a tweeter, could be 2.5 or 3-way, could be passive bi / tri-amped, or active bi/tri-amped not sure yet, open to all scenarios.
Most 3” drivers in the 84 - 88db SPL range roll-off around 120 – 100hz and at 50hz they are around 72db – 73db. That’s if the specs are not inflated. Was told that the specs at 1 meter are based on low voltage and do not translate to real life…not sure what it means.
If I want it to be flat from 50hz to 2000khz or 4000khz at around 80 db then cross with a tweeter, what is the solution without adding any gain via tone control to that 50hz-120hz range or any color to the sound?
Running two 3” in parallel would add 6db so I’m already at my 79db - 80db from 50hz to 120hz, but after that if I want to run only one 3” as mid range up to the tweeter.
What type of filter or EQ or solution is needed to run one 3” from 50 to 100hz at it’s full SPL, then cut it off either 6 or 12 db slope, then past that 100hz mark somehow the second driver drops by either 4 or 8db depending on the tweeter I choose not sure on the slope to avoid too much mud in the middle.
Can this be solved without DSP? And how efficient will it be without any peaks or too much mud in the low mid to mid section?
I can pick tweeter with low FS to match the slope of my 100hz so if its first order at 100hz I can probably push the mid range to 4000khz cross over.
In general if it’s off by 1,2,3, 4 dbs…. how much can an average human hear these 1-3 db peaks and valleys at such a close range of 1-2 feet, so if this problem is not solvable without adding gain or adding too much color with too much EQ adn have to live with minimal peaks and valleys?
Cheers.
A lot depends on what you call small. And how loud you listen (not very loud given the near-field). A fellow in Japan EQes a pair of Mark Audio A5 down into the 30s. Won;t play all that loud thou.
Why one would add a tweeter to a 3” when you can get really good 3” FRs that are better than many pricey tweeters.
If you use 2 in a 1.5 way system the liit to bass/volume due to cone area limits will be reduced. You could even go with 3 if you choose a 4Ω driver.
dave
Why one would add a tweeter to a 3” when you can get really good 3” FRs that are better than many pricey tweeters.
If you use 2 in a 1.5 way system the liit to bass/volume due to cone area limits will be reduced. You could even go with 3 if you choose a 4Ω driver.
dave
Instead of two 3" midwoofers, you could take one Purify PTT4.0x4 midwoofer in 4-5 liter cabinet. that will get you pretty close to your target. At a price though: some 300 € or $ a piece.
If you want an honest 50 Hz, I wouldn't try less than 6.5". There will be less EQ'ing, less power required and less driver stress. No need to try and change the rulebook.
Lets try this again, if I do not want to compromise on any of your suggestions, meaning I have a certain size aesthetics I want, I have certain drivers with certain sound quality I want and I don't like the high end of a 2" to use it as a full range, so basically no compromise at all, given my scenario which I outlined in the beginning, is there a viable solution?
I have a pair of very cheap Citizen computer speakers which are full range 2.5" drivers called "p3duc" they have tone/treble control with this amp: https://quasarelectronics.co.uk/Item/3090h-3w-stereo-amplifier-module-ba5406-with-heatsink
I suspect the tone on bass is 24db I have it at about 60% so maybe 18 - 20db, treble is all the way to it's max still very muddy up top. As reference they give me more then enough bass, but it's a bit muddy and poor high end. I realize these are very cheap components, but as reference I don't see any need to go past 3" at such a close listening range. What I don't know is what SPL I'm listening too, the volume on these is on its max, but on my MacBook air 13" I'm at half way to about 3/4 that's it, plenty of volume for me.
I have a pair of very cheap Citizen computer speakers which are full range 2.5" drivers called "p3duc" they have tone/treble control with this amp: https://quasarelectronics.co.uk/Item/3090h-3w-stereo-amplifier-module-ba5406-with-heatsink
I suspect the tone on bass is 24db I have it at about 60% so maybe 18 - 20db, treble is all the way to it's max still very muddy up top. As reference they give me more then enough bass, but it's a bit muddy and poor high end. I realize these are very cheap components, but as reference I don't see any need to go past 3" at such a close listening range. What I don't know is what SPL I'm listening too, the volume on these is on its max, but on my MacBook air 13" I'm at half way to about 3/4 that's it, plenty of volume for me.
It is very hard for small to go low, loud, and undistorted. Even asking a 3inch driver to do 80db at 50hz is asking a lot. A more realistic goal is 100hz and a small sub. I forgot the name of it but there is one tiny driver that will do 40hz and up over 20khz but it is very expensive And very inefficient. Without massive EQ boosting the lows you have cut the mids and highs way down. It’s pretty much like asking for a 1000hp half liter engine. You can’t wear headphones?
The problem is I don't know how loud does 80db sounds like, maybe it's already too loud and I only need 70db. All other options are no on the table as fa as subs headphones......etc just a pair of speakers.
In theory what I'm asking has actually nothing to do with 80db or 70 db flat, it has to do with any design where you want to use two drivers to run both of them at certain frequency then cut off one and run the other one at lower frequencies to match your lowest frequency db.
All I know is Dunlavy SM-1 is an MTM with two 6.5" mids and it can run almost flat from 60hz to 20,000 khz at about 91db or so. So he made it work somehow, since I do not need 91 db maybe it can be done with smaller 3" drivers running flat at much lower db.
Here is the picture of that cross -over, this picture was posted by another user many years a go, maybe something can be extracted from his design. Can we even tell if it's 2-way, 2.5 or 3-way.
In theory what I'm asking has actually nothing to do with 80db or 70 db flat, it has to do with any design where you want to use two drivers to run both of them at certain frequency then cut off one and run the other one at lower frequencies to match your lowest frequency db.
All I know is Dunlavy SM-1 is an MTM with two 6.5" mids and it can run almost flat from 60hz to 20,000 khz at about 91db or so. So he made it work somehow, since I do not need 91 db maybe it can be done with smaller 3" drivers running flat at much lower db.
Here is the picture of that cross -over, this picture was posted by another user many years a go, maybe something can be extracted from his design. Can we even tell if it's 2-way, 2.5 or 3-way.
80db is a good target, Is the 3 inch driver an arbitrary choice or a size limit? We really need to know how large (more wide) it can be to give good advice. Using even a slightly bigger driver like a 4 inch would make the goal much more archievable, you just have to be smart by not making a idiotic wide cabinet as most tend to do, fitting a 4 inch driver in a 12cm cabinet should be possible while only having a 2 cm increase (almost neglectable) in width which gives 33% more excursion and cone area which are highly desirable parameters for archieving good bass. A 5 inch would be even better and would most likely archieve your goals. Which would also mean you need a tweeter which in my eyes would be a positive addition as I find the upper treble not that good on most fullrange units, but maybe if you're a bit older or have worse(r) hearing that may be (an) acceptable (compromise) for not having to make a crossover and buy another drive unit.... If you go for a tweeter I would place the crossover point as low as possible as the tweeter can handle it (low spl requirement) and would make the tweeter less obvious while listening (a good thing)
It's an interesting problem. Unfortunately, I don't know of a solution.
With no port to augment the bass, and since you want a 50 Hz lower cutoff frequency, you ideally need a 3" driver with a self-resonant frequency (f0) below 50 Hz. I don't know of such a thing, and a quick search on Digikey turned up no drivers of this size with such a low f0. As mdpaudio said, there are 3" woofers with f0 around 100 Hz. But I can't find any lower than that.
If such a speaker exists at all, it is going to be a very rare bird, and it still may not produce enough SPL at 50 Hz to audible. The human ear is very insensitive at these low frequencies, which adds to the difficulty.
The trouble isn't technology - it's fundamental physics (acoustics). Mice squeak, lions roar. Small dogs yap, big dogs woof. Why do animals with small throats make higher-pitched sounds? Why are there no mouse-sized creatures that roar with a deep voice like a lion? Why has evolution never managed to engineer such a creature, after some 3 billion years of continual experimentation?
Well, for the same reason why tiny woofers cannot make deep bass (roar), though they can can get quite loud at higher frequencies (squeak).
Bass response from a driver in a sealed cabinet falls at 12 dB/octave once you get below the resonant frequency of that speaker in that box (Fc). Let's imagine you started with a sealed box frequency response which was 3 dB down at 100 Hz. At 50 Hz (your target), response would be roughly 12 dB down. To bring that back up, you would need 12 dB more power, which is roughly 16 times as much power as you'd need at higher frequencies.
Small speakers run out of excursion at such low frequencies, so you can't just feed lots of watts into one (it will tear itself apart). You might get there with multiple 3" woofers sharing the drive signal, but expect lots of distortion - when you drive a speaker below its resonant frequency, harmonic distortion increases rapidly as frequency goes down.
Cal suggested you'd need at least a 6.5" speaker. You can get roughly the same cone area as one 6" speaker by using four 3" speakers. (But it will probably cost four times as much, and the box volume will need to be four times as big as one speaker needs. You'd still need to apply the big bass boost, but there is a better chance of the drivers being able to survive it.)
By the way, you are not alone; consumers have been wanting tiny speakers along with deep rumbling bass for a long time now. Nobody knows how to make this happen (mice don't roar). The practical solution is the one the home theatre industry ended up settling on: one relatively big subwoofer, and two or more smaller satellite speakers.
A lot of the time, because of consumer demand for really tiny satellite speakers, there is a "hole" in the frequency response of these sub/satellite systems, because the tiny satellite speakers can't reach low enough frequencies to mate up with the subwoofer. Between the upper frequency limit of the subwoofer, and the lower frequency limit of the satellites, there is a canyon in the combined frequency response.
It will be interesting if you manage to find the no-compromise solution you want. I don't think there is a very good chance it will happen, sadly.
-Gnobuddy
The following links (loudness of various everyday sounds) will help you get an idea what 80 db sounds like:
1) https://www.audicus.com/noise-levels-of-everyday-sounds/
2) https://noiseawareness.org/info-center/common-noise-levels/
3) https://decibelpro.app/blog/decibel-chart-of-common-sound-sources/
If you read through all three lists and compare, 80 dB SPL is roughly the volume of a loud alarm clock, a whistling kettle, a doorbell, a ringing telephone, the sidewalk of a street with moderate traffic.
For me, that is quite loud enough, most of the time. (Your hearing starts to be damaged by sounds louder than about 85 dB; the longer you listen to such sounds, the deafer you become.)
70 dB is often listed as roughly the loudness of a household vacuum cleaner. To me, that is pretty loud, and I consider it the loudest sound I should ever make in my apartment, in order not to disturb my many senior-citizen neighbours in my apartment building.
The easiest way to achieve this is by using an active crossover filter, and bi-amplifiying. The filter splits up incoming frequencies into high and low bands, and the two filter outputs go into two separate power amplifiers, one driving the woofer, the other driving the tweeter. Simply adjusting the volume of one of these will balance the SPL of the tweeter to match the SPL of the woofer at the crossover frequency.
Since this is a stereo system, you need two of everything. Two active crossover filters, four power amplifiers in all. This would have been incredibly expensive two decades ago, but nowadays we have cheap, high-quality class-D power amplifier boards and modules that are perfect for this sort of job.
If you look around, you may find ready-made circuit boards or modules that do most or all of what you want.
Your picture shows a passive crossover network. They are very hard to get right; easy ones work badly, and ones that work well are difficult to design. Using an active crossover and bi-amping is a much better solution for DIY.
Some simple math: the area of a 6.5" diameter circle is 33.183 square inches. Two 6.5" circles have a combined area of twice that, or 66.366 square inches.
A single 3" circle has an area of 7.069 square inches.
Do you see the trouble? The 2x6.5" Dunlavy speaker has more than NINE TIMES the woofer cone area of a single 3" woofer. The Dunlavy is a (small) lion, the 3" woofer is a mouse...but you want the mouse to roar in as deep a voice as the small lion.
-Gnobuddy
You are so kind to have written all you have when this statement really says so much.
You a somebody, not a Gnobuddy.
Cheers
FYI/FWIW/YMMV, I've measured quite a few folks over the decades and most of us watch prime time TV in the mid 60s on average ( a little bit louder than conversation) regardless of the listening distance and action movies, musical shows in the low 70s (a little bit louder than a washing machine or dishwasher).
Lots of good feedback here, and yes I do know about the lion vs. mouse concept, I think the issue is I simply do not know how loud do I need things to be so I simply swan for the fences saying I want it flat at 80db and on top of that I was just assuming I need 50hz, since it’s the range of a modern EDM / Hip Hop kick drum.
I do not want to go past 3” even wanted 2”, at such a close range I want a very slim and tall cabinet not fat and stumpy, so 3” is cut off and cabinet width as narrow as I can squeeze the 3” driver into it, height on the other hand is not an issue I can make it as tall as the FS volume requires it.
Here is what I really want to know, what type of device can zoom into a driver’s specific frequency and cap it with linear cap. So in my case if a driver is 88spl, so from 50hz – 120hz from 73db it gradually gets louder then its flat at 88 spl, what device would follow it where it will make it quieter past 100hz or the frequency I decide and then it’s linear past that frequency at lets say 80db.
Filters have slopes so it’s not linear, L-pads are linear but not tied up to frequency it would have to be some type of limiter that detects certain db at certain frequency and cuts off some db below certain threshold. Is there a simple low noise no color circuit that does that if we knew the frequency where it becomes linear?
If not, lets look at other options:
1) Adding gain to the bass, what is the cleanest less colorful solution to add more bass to that 50 -100 hz range.
If a 3” driver is rated at 30W nominal and 60W program, so if that driver is running only up to 100hz then cut off via first or second order, what is the limit on dbs we can add via more wattage with bigger amp on active system before we blow it?
2) Baxandall Tone is that the least noisy least colorful gain?
3) Is it maybe better to cut all drivers to the lowest point of lets say 60db then try to raise all of them via single volume ….is that too much color and noise added?
4) Avalon U5 DI, many years a go I went thru a lot of high end gear as hobby didn't even know how EQ's work just like turning those konbs adn listenign to the sound change it's character, U5 was by far the best bass pre-amp I had specially for bass guitar, I went thru Neves, and few other pre-amp EQs……in the 3k- 5k price range, nothing came close as far as clean lots of headroom non colored no personality sound. It’s actually hard to describe its character since it has no personality but it’s 30db boost was so clean on low end.
When i Google U5 schematic two sites come up:
Scroll thru to second page they have semi-finished schematic
This one is more of a summery of that schematic
https://t-sap.com/index.php?option=com_content&task=view&id=51&Itemid=41
I have no idea on how to read these, but if we separate the headphone, balanced and all other connections from that board and focus only on the boost of 30db …can anyone tell exactly what type of circuit do they use to get such large gain yet it was so clean not muddy, lots of headroom.
If somehow that 30db boots section can be separated from the whole Di and produced as a smaller size stereo module. I’m all in on not spinning in a wheel like a hamster trying to find other solutions vs. just boosting the low end.
In general are there any pre-made modules with tone control that would be build on similar schematic as U5, I mean both active crossover and the amp to drive it. It says U5 is 20 watts, but it’s a Class A mono so that would accumulate to a lot of modules for 4-6 drivers and possibly tons of heat since it’s Class A.
Cheers
I do not want to go past 3” even wanted 2”, at such a close range I want a very slim and tall cabinet not fat and stumpy, so 3” is cut off and cabinet width as narrow as I can squeeze the 3” driver into it, height on the other hand is not an issue I can make it as tall as the FS volume requires it.
Here is what I really want to know, what type of device can zoom into a driver’s specific frequency and cap it with linear cap. So in my case if a driver is 88spl, so from 50hz – 120hz from 73db it gradually gets louder then its flat at 88 spl, what device would follow it where it will make it quieter past 100hz or the frequency I decide and then it’s linear past that frequency at lets say 80db.
Filters have slopes so it’s not linear, L-pads are linear but not tied up to frequency it would have to be some type of limiter that detects certain db at certain frequency and cuts off some db below certain threshold. Is there a simple low noise no color circuit that does that if we knew the frequency where it becomes linear?
If not, lets look at other options:
1) Adding gain to the bass, what is the cleanest less colorful solution to add more bass to that 50 -100 hz range.
If a 3” driver is rated at 30W nominal and 60W program, so if that driver is running only up to 100hz then cut off via first or second order, what is the limit on dbs we can add via more wattage with bigger amp on active system before we blow it?
2) Baxandall Tone is that the least noisy least colorful gain?
3) Is it maybe better to cut all drivers to the lowest point of lets say 60db then try to raise all of them via single volume ….is that too much color and noise added?
4) Avalon U5 DI, many years a go I went thru a lot of high end gear as hobby didn't even know how EQ's work just like turning those konbs adn listenign to the sound change it's character, U5 was by far the best bass pre-amp I had specially for bass guitar, I went thru Neves, and few other pre-amp EQs……in the 3k- 5k price range, nothing came close as far as clean lots of headroom non colored no personality sound. It’s actually hard to describe its character since it has no personality but it’s 30db boost was so clean on low end.
When i Google U5 schematic two sites come up:
Scroll thru to second page they have semi-finished schematic
This one is more of a summery of that schematic
https://t-sap.com/index.php?option=com_content&task=view&id=51&Itemid=41
I have no idea on how to read these, but if we separate the headphone, balanced and all other connections from that board and focus only on the boost of 30db …can anyone tell exactly what type of circuit do they use to get such large gain yet it was so clean not muddy, lots of headroom.
If somehow that 30db boots section can be separated from the whole Di and produced as a smaller size stereo module. I’m all in on not spinning in a wheel like a hamster trying to find other solutions vs. just boosting the low end.
In general are there any pre-made modules with tone control that would be build on similar schematic as U5, I mean both active crossover and the amp to drive it. It says U5 is 20 watts, but it’s a Class A mono so that would accumulate to a lot of modules for 4-6 drivers and possibly tons of heat since it’s Class A.
Cheers
Expensive though: (..and not sure about availability anymore)
https://audience-av.com/oem-diy-parts/a3/
https://audience-av.com/oem-diy-parts/a3/
https://www.diyaudio.com/community/...akers-the-reference-mini-build-thread.305159/
This thread shows one way to go. Maybe a bit bigger than you planned, but certainly with the Purify, true miracles can be worked in just 4 litres.
Other options do exist , but are not available to the diy crowd. Sonos /Dan Wiggins used to be active behind the scenes in developing propriatory very large excursion mini woofers.
This thread shows one way to go. Maybe a bit bigger than you planned, but certainly with the Purify, true miracles can be worked in just 4 litres.
Other options do exist , but are not available to the diy crowd. Sonos /Dan Wiggins used to be active behind the scenes in developing propriatory very large excursion mini woofers.
T/S theory peters out at the driver's upper mass corner (Fhm) = 2*Fs/Qts' and from there till it gets to the VC coil diameter it's mass controlled, so a band-pass filter (CD horn EQ) could be used to flatten it to a lower frequency and a high Qt driver is desirable, but then the cab gets big or needs to be OB.
[Qts']: [Qts] + any added series resistance [Rs]: http://www.mh-audio.nl/Calculators/newqts.html
[Rs] = 0.5 ohm minimum for wiring, so may be higher if a super small gauge is used as a series resistor plus any added resistance from an XO/whatever.
You could look at a two way with a full range driver paired with a mini sub driver like the be w5-1138smf. This fits into tiny cabinets and if you cross to a small full ranger the overall enclosure could stay quite small
You could mount one (or two?) larger woofer (4"-6") on the side of the box to keep it slim.