Well, that's not true at all.
1.6khz? 8'' driver?
There is 8'' drivers out there that performs very well even above 10-15khz...
1.6khz is nothing, especially for a 8''...
The beaming is usually very progressive and becomes ''laser like'' in the higher frequencies only.
Agreed: using a 12'', 15'' or 18'' as a midrange is optimistic. For few reasons. But up to 1-1.5khz? Not a problem at all, especially if brickwalled with steep slope crossover.
ALSO, I'd like to point out something.
Two years ago I conducted a blind test, which involved midrange drivers. Many different drivers, not even all midranges, some woofer as well. From a 2'' compression to 10'' PA and 3'', 5'' and 8'' cones.
We were testing two at a time, each installed on a rotative enclosure. All EQd and SPL-calibrated so they can have the same flat output from 400hz to 6300hz.
Wait for it...
NOBODY, and I mean NOBODY, could spot any one of them from each others. Even the Dayton WOOFER could not be identified from the Radian 950PB-BE compression (!) when crossed 400-6300hz and SPL-leveled.
Of course, at the end, when the frustration started to hit, we begun to swing our heads to spot them by directivity. Easy, no? Well, NO. Didn't help at all.
Even the 3'' Faital v.s. the Eminence 10'' couldn't be identified one from another, directivity-wise, tone-wise or else.
And we're talking 6300hz.
So bottomline, what's left to do?
Choosing high energy drivers that can cover 4-5 octaves... and using an EQ.
I see no reason to get picky over midrange drivers anymore.
I'm really the wrong person to ask, as i only use them for sub use, almost always crossing at 100Hz.
I can see how folks could be happy with them at higher frequencies from a directivity point of view.
Given about a 14" diameter piston excluding the surround, that would equal ka=2 a little above 600Hz, which i believe is widely consider acceptable.
(ka being driver circumference / wavelength).Speaker Off Axis: "Correct" Driver Diameters for Great Off Axis Response - Acoustic Frontiers
For me, the bigger issues with going higher are:
center-to-center spacing between sub and mid, which for an 18" sub and say a 10" mid, goes beyond 1/4 wavelength at about 250 Hz. Only gets worse going higher with a smaller mid.
This makes it harder enough just to build a conforming box, and really screws up satellite subs.
And most importanly it's too easy to hear sub localization above 100Hz.. ime/imo.
I also wonder when a driver looses pistonic control. If anybody can cite a good rule of thumb based on diameter, please do.
I have to believe much of the response measured at higher frequencies from an 18" is breakup output. Dunno.
Anyway, the few times I've tried running either the bms 18n862 or faital 18FH500 up to 650Hz, it didn't really work. Lost both clarity and dynamics.
I typically have 12"s in between the 18"s and a bms coax CD, with sub to 12" crossing at 100Hz, and 12" to CD at 650Hz.
So the idea obviously, was to skip the 12"s....which would have been great if it worked.
That's the frequency response of the 18FH500. Tested myself and what FaitalPro provide is accurate.
So, up to 650hz the on-axis response is basically the same as the (very) off-axis of 45 deg.
Now, it's very manageable up to 1100hz.
1600hz is optimistic if really 45 deg is important for your project.
Would like to see some 30deg off-axis and even 15deg off-axis responses but there is none.
That being said. Using a 18FH500 only up to 200hz is a waste. Pretty much like buying a Porsche GT3RS or a Ferrari 488 pista and never bring it on a racetrack. You CAN do that, but it's a waste nonetheless.
At the very least, 400-500hz. But 200hz? Nope.
Might as well choose a more appropriate driver to cover the low-end.
This driver might be the answer I am looking for. I need to cover 125-750hz with authority, articulation and dynamic prowess all bundled in one. You think ?
Hey Scott,
I can recommend this PD.158 great 15 inch driver to cover 100Hz to 800Hz band with absolute authority and detail.
I will post a sim in a mo... I built a pair and they delivered exactly as the sim suggested... Stunning.
I believe the Mms to Bl ratio of any driver is vital, and as a rule of thumb, the lower the figure better ie The 15 inch PD 158 with a 4 inch voice coil (avoid 3 inch VC's on a 15 inch driver) has a Mms of 85.23g and a BL of 25.39 = 3.35.
I can recommend this PD.158 great 15 inch driver to cover 100Hz to 800Hz band with absolute authority and detail.
I will post a sim in a mo... I built a pair and they delivered exactly as the sim suggested... Stunning.
I believe the Mms to Bl ratio of any driver is vital, and as a rule of thumb, the lower the figure better ie The 15 inch PD 158 with a 4 inch voice coil (avoid 3 inch VC's on a 15 inch driver) has a Mms of 85.23g and a BL of 25.39 = 3.35.
Sim for PD 158
Here is the Sim for the PD 158, also I included the 18 inch version which I couldn't afford, but is way better suited to sub duties ie 20Hz to 100Hz band.
Here is the Sim for the PD 158, also I included the 18 inch version which I couldn't afford, but is way better suited to sub duties ie 20Hz to 100Hz band.
@JonBocani: the why is in the link mark100 posted. As what we hear is the direct + indirect sound (on+off axis) you want the off axis response to be similar as the on axis to get a natural sound.
With FR drivers the dustcap often acts like a tweeter like a wizzer cone to get wider off axis response in the highs.
A second thing (many) small (light) drivers do better then big drivers is detail resolution.
I don't know what test you did and in a highly dampened room or outdoors drivers sound more similar due to minimal indirect (off axis) sound, but if you hear no difference in drivers you might want to get your ears checked.
Please get that all sound but the on axis sound is off axis. So on axis frequency response does not tell you much about how the driver sounds. Check the first link in my signature.
With FR drivers the dustcap often acts like a tweeter like a wizzer cone to get wider off axis response in the highs.
A second thing (many) small (light) drivers do better then big drivers is detail resolution.
I don't know what test you did and in a highly dampened room or outdoors drivers sound more similar due to minimal indirect (off axis) sound, but if you hear no difference in drivers you might want to get your ears checked.
Please get that all sound but the on axis sound is off axis. So on axis frequency response does not tell you much about how the driver sounds. Check the first link in my signature.
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Yes absolutely, it's a no brainer.
Can't imagine anyone being unhappy with that driver used from 125-750hz...Even the pickiest.
Now, if brickwalled, would it be better than a 15PR400? I don't know.
On the other hand, the 18FH500 wins hands down if used from, say, 70hz instead of 125hz.
Simply put: the 15PR400 is not really made to enter in subwoofer's territory, but the 18FH500... Yes.
Nice, how do they sound (I'm considering them)? Are there some problems above 300hz or do you mean 18 inchers in general?
Any measurements?
Here they are used with >1,5kHz acoustical xo point in a 2-way😀😱: https://www.prodance.cz/data/attachments/mereni_18ps76+cd3030t3+me90.fl_.pdf
Funny you mention that, I actually had my ears checked just after that very test. Had it checked TWICE, from different labs. I'm not even kidding, i'm dead serious.
Excellent shape for my age, especially HF: 21khz one ear and 23khz the other, but a dip around 3.5khz which coincide with the pitch of my wife's voice when she's asking to clean the garage.
I go back and fourth between audio minutia and the real audibility threshold of the human ear.
There are wake up calls when I find I have accidently changed a crossover point on a channel and don't catch it for a couple of days....yet I get caught up with shiny new toys. Must be the dopamine rush of something new that keeps me going.
You're right though...clean output and frequency response is the main criteria for good sound. Been trying this in practice with different driver types and power response.
There are wake up calls when I find I have accidently changed a crossover point on a channel and don't catch it for a couple of days....yet I get caught up with shiny new toys. Must be the dopamine rush of something new that keeps me going.
You're right though...clean output and frequency response is the main criteria for good sound. Been trying this in practice with different driver types and power response.
18's in general. Not that they can't work high, it just becomes much more difficult to keep box issues from effecting the sound. Open baffle would probably work well.
They sound pretty good to me. Have them in 200L for each driver. Can't tell a difference between them and my BMS 15N850 when used below 300hz within excursion limits. My boxes aren't quiet enough to sound good higher up.
Pretty sure most modern prosound drivers from reputable companies will work well.
The test was made indoor, IEC specs listening room. The whole test was following a bulletproof methodology and was not some basement test made just for fun.
Agreed: on paper there is all the reasons in the world to believe transducers will sound very differently in all sorts of ways.
Problem is: when a listener, a human, is confronted with the reality, via a blindtest, it's not that obvious at all, those differences on paper...
The human ear can spot a 0.3-0.5db variation -at best- and 1/6-1/3 octave variation -at best- ...and if not focused I'd say most people wouldnt notice a 1-1.5db variation and as much as 1 full octave.
Not to mention that spotting other things such a flimsy 160kbps MP3 was nose-bleeding. At 256kbps, forget it. No human I know of can spot a 256kbps MP3 and even less a AAC in such controlled blindtest...
The human ear is a major, major bottleneck. Wildly overrated ''tool''.
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+1
15's or 18' and even 12's... same issue.
Either open baffle or treated enclosures...or you live with the non-hifi ''PA sound''
while very clean high up looking at the waterfall, of off-axis response clearly shows where the compromise was made. I’m wondering if it would not sound better if the CD would play a bit lower?
Another blank statement which is not true! There are several drivers from Celestion that have excellent performance without any "rings" This one is cheap, yet low distortion without engagement ring😀
MONACOR: SP-10/250PRO
Hi,
I don't see 5th elements statement as blank. It is true for most drivers type however...
If we look enough we will always find exception but it is true that demodulation rings help a lot to reduce distortion.
Being it a Bms or a Dayton... 😉
Not just Celestion, there are many drivers from other manufacturers without shorting rings and top-notch distortion levels. On the flipside, there are many drivers with shorting ring(s) and with disappointing results.
"I would add that, on the whole, I wouldn't want to use any Pro driver that didn't have copper or aluminium demodulating/shorting rings."
If that is not a blank statement, I'm a French unicorn😉 Would you like me to describe all French people to be ignorant of language? I know it is not true...
I see no problem with what 5th said. What would he like to use or not is a matter of his personal preference. Knowing where he comes from i stated two drivers that would probably meet his harsh criteria based on distortion that don't have demodulation rings or copper sleeves. It certainly wasn't a call for a debate if he is wrong or not.