Yes, the 10 inch PD is really a 100 Hz to 1,000 Hz driver... look at that frequency response... Thats one well sorted driver!
In an ideal world you would use a separate bass driver below 100 Hz... But if you dont need the 126 dB continuous SPL in your lounge (who does?!) you can get remarkable quality bass at lower 90 dB to 100 dB SPL with low power and low cone movement and that equals low distortion... See my long A** post above!
Good point... If you look at a full frequency spectrum 3D graph there is a lot of higher frequency harmonics info on many low frequency fundamentals so you need good crossovers and mid top to get the best bass!
If you think a 10” driver with (arguably disputable, I’ve not seen a Klippel current/excursion plot) 2,5mm Xmax will do serious low end reproduction for a studio monitor, you either don’t turn up the volume or don’t recognize distortion. No, I’m not bashing PD drivers, they make excellent ones, but this one just isn’t a bass driver. They tell you themselves.
That, at 50Hz, is a 'staggering' 95dB SPL 1m half space before things run away from the magnet gap. You need some headroom, so effective listening volume would be about 75-80dB at 2m. Is that enough for critical mixing? Some 6" reflex does better.
Fun fact, a lot of people mistake the H2 for the real low frequency. Lacking low end capabilities often are accompanied by high levels of harmonic distortion.
That, at 50Hz, is a 'staggering' 95dB SPL 1m half space before things run away from the magnet gap. You need some headroom, so effective listening volume would be about 75-80dB at 2m. Is that enough for critical mixing? Some 6" reflex does better.
Fun fact, a lot of people mistake the H2 for the real low frequency. Lacking low end capabilities often are accompanied by high levels of harmonic distortion.
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Hydrogen Alex used the wrong diameter in his model, the PD103NR1 has an Sd of 362cm3, not 490.9cm3.
Also, it's AES power rating is 70Hz to 700Hz (free air), it is doubtful a mid-range driver with 31grams Mms cone will survive (long) when subjected to 75 volts an octave lower in a sealed box.
If we assume it's 7.5mm Xmax to be correct (~10%+ distortion..) it would sound less than half as loud at 40Hz than the Dayton Audio RSS265HF-8 in a sealed box:
The PD103NR1 would be at least -5dB from your stated goal of ~105dB at 40Hz.
In my opinion, a monitoring system used for modern music should be capable of output down to 20 Hz at a reasonable level, a pair of RSS265HF could do around 100dB that low.
100 dB SPL at 20Hz sounds about as loud as 60dB at 100Hz.
Art
Mark,
We can exchange opinions in a mo, but first I must correct your figures...
Your quote:
"at 50Hz, is a 'staggering' 95dB SPL 1m half space before things run away from the magnet gap"
This is utter garbage... If you were a commercial company making such false accusations Precision Devices could take you court for deformation!!
Facts first: A single PD 103 NR1 will do 98.5 dB at 50 Hz with 80 watts with 2.5mm cone travel.... Well within its Xmax of 7.5mm!
A pair in room will hold a continuous 101.5 dB SPL at 1 meter before any wall / boundary gain, see accurate Sim below .
Show me any of your "6 inch drivers that can do better" and I will be happy to draw accurate and valid comparisons.
Your quote:
"I haven't seen a Klippel current/excursion plot"
The driver spec sheet states it is "Klippel Verified" (See screen shot below)
Your quote:
"Fun fact, a lot of people mistake the H2 for the real low frequency.
I have never made this mistake, I doubt the Precision Devices designers would have either.
Your quote:
Lacking low end capabilities often are accompanied by high levels of harmonic distortion."
Agreed, but to applicable here as we are talking 80 watts and +/_ 2.5mm cone movement... vanishing low distortion and of course time domain accurate (sealed box, no ports/transmission lines/delayed resonance etc)
Opinion:
(1) I believe many DIY loudspeaker guys are from the lets say..."Silver Surfer" age bracket (I certainly am) and we can often find it hard to let go of the past, we hold on to long held technical beliefs and hardware that were valid for decades... ie There is a lot of : "I always remember that unforgettable listening experience... The gear was an XYZ with a pair of ABC powered by a PQR ... OMG... Nothing has ever come close..."
Combine this with an element of "It cant be that simple...Too good to be true" and arrive at the
"Circle the wagons lads its time to De-Bunk this new fangled tech...!
Now I really am going to pi** o** the old guard, but here we go:
I believe you can take all the complex speaker design books from the last 100 years and ignore the lot!
Its so easy.... Just use decent Pro Drivers with a few key specs, bolt them into a small rigid sealed box, add an decent AMT type tweeter and bend with decent but affordable DSP and Eq in room to taste... Job done!
You can DIY play with amplifiers/cables/sources to your hearts content cause the speakers are a walk in the park!
Love it or hate it the days of passive crossovers "black art of speaker designing" are long gone... Anyone can get good results easily...If you have big $$$ you get astonishing results... All within easy reach and a few weeks research and a few hours of You Tube tutorial viideo.
We can exchange opinions in a mo, but first I must correct your figures...
Your quote:
"at 50Hz, is a 'staggering' 95dB SPL 1m half space before things run away from the magnet gap"
This is utter garbage... If you were a commercial company making such false accusations Precision Devices could take you court for deformation!!
Facts first: A single PD 103 NR1 will do 98.5 dB at 50 Hz with 80 watts with 2.5mm cone travel.... Well within its Xmax of 7.5mm!
A pair in room will hold a continuous 101.5 dB SPL at 1 meter before any wall / boundary gain, see accurate Sim below .
Show me any of your "6 inch drivers that can do better" and I will be happy to draw accurate and valid comparisons.
Your quote:
"I haven't seen a Klippel current/excursion plot"
The driver spec sheet states it is "Klippel Verified" (See screen shot below)
Your quote:
"Fun fact, a lot of people mistake the H2 for the real low frequency.
I have never made this mistake, I doubt the Precision Devices designers would have either.
Your quote:
Lacking low end capabilities often are accompanied by high levels of harmonic distortion."
Agreed, but to applicable here as we are talking 80 watts and +/_ 2.5mm cone movement... vanishing low distortion and of course time domain accurate (sealed box, no ports/transmission lines/delayed resonance etc)
Opinion:
(1) I believe many DIY loudspeaker guys are from the lets say..."Silver Surfer" age bracket (I certainly am) and we can often find it hard to let go of the past, we hold on to long held technical beliefs and hardware that were valid for decades... ie There is a lot of : "I always remember that unforgettable listening experience... The gear was an XYZ with a pair of ABC powered by a PQR ... OMG... Nothing has ever come close..."
Combine this with an element of "It cant be that simple...Too good to be true" and arrive at the
"Circle the wagons lads its time to De-Bunk this new fangled tech...!
Now I really am going to pi** o** the old guard, but here we go:
I believe you can take all the complex speaker design books from the last 100 years and ignore the lot!
Its so easy.... Just use decent Pro Drivers with a few key specs, bolt them into a small rigid sealed box, add an decent AMT type tweeter and bend with decent but affordable DSP and Eq in room to taste... Job done!
You can DIY play with amplifiers/cables/sources to your hearts content cause the speakers are a walk in the park!
Love it or hate it the days of passive crossovers "black art of speaker designing" are long gone... Anyone can get good results easily...If you have big $$$ you get astonishing results... All within easy reach and a few weeks research and a few hours of You Tube tutorial viideo.
Sorry Art, you are 100% wrong, on multiple counts...
(1) Every sim is diameter 25cm (10 inch driver) ... Dont know where you are getting your ideas from?
(2) You are also wrong about the AES power rating ... The driver is rated in a 975 liter sealed enclosure (see screen shot bottom left)
(3) You are also wrong... No, only joking, I just like saying it now 🤣
Your opinion re what monitors should do does not count, only facts and what the OP requested is bass SPL at 40Hz and 50Hz... Not your opinion that "a monitoring system used for modern music should be capable of output down to 20 Hz at a reasonable level"
(4) You are also wrong... Ahh, thats better🤣 (!) Your quote: "it is doubtful a mid-range driver with 31grams Mms cone will survive (long) when subjected to 75 volts an octave lower in a sealed box."
75 volts... WTF? Look at my sims (all accurate and on 10 inch driver Sd)... We are talking 80 to 250 watts on a driver rated for 700 watts continuous (6dB not the usual 3dB peaks so 2,800 watt peak power handling!) and in "your opinion" you doubt it will last long in a sealed box" Art, have you and mark been drinking the same special cool aid again!🤣🤣🤣🤓
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Personally I think it is about how quickly the cone stops when the input signal ceases.
Which is why I usually prefer active speakers as the movement and the cessation thereof is better controlled.
I also prefer ported speakers provided they are suitably high-passed. The port greatly reduces cone movement and excessive cone movement raises distortion.
I agree with you Charles re your quote: "Personally I think it is about how quickly the cone stops when the input signal ceases."
I disagree re ported... I am a fan of sealed box or open baffle, and also active with good DSP... The A to D converter is key if you use analog inputs... Really got to spend good $$$ on that part as well as the A to D and DSP.
Cheers
A.
I disagree re ported... I am a fan of sealed box or open baffle, and also active with good DSP... The A to D converter is key if you use analog inputs... Really got to spend good $$$ on that part as well as the A to D and DSP.
Cheers
A.
I also calculate about 95 dB SPL from a 10" cone driven to +/- 2.5mm at 50 Hz. I am assuming a 10" cone has an Sd of about 360 cm^2 which translates to an effective diaphragm diameter of 21.5 cm.
If I use an effective diaphragm diameter of 25 cm (for an Sd of 490 cm^2), then I match Hydrogen Alex's 98.5 dB at 50 Hz at +/- 2.5mm. Unfortunately, 25 cm diameter cones are most often found on 12" drivers.
I think @weltersys diagnosed the cause of the confusion.
If I use an effective diaphragm diameter of 25 cm (for an Sd of 490 cm^2), then I match Hydrogen Alex's 98.5 dB at 50 Hz at +/- 2.5mm. Unfortunately, 25 cm diameter cones are most often found on 12" drivers.
I think @weltersys diagnosed the cause of the confusion.
Same as a fast attack a fast (immediately) stopping "bass" signal will be reproduced by midrange/tweeter, for the fast parts.
Edit: in other words - only a infinite sine signal is free of harmonic contents.
This is not how music works the signal doesn't just abruptly cease. Every note/sound played is followed by a natural decay in the recorded signal and the amplifier controls the motion of the cone back to a stop.
The only time this changes is around resonance at low frequencies, so you'll get a bit of undershoot or overshoot, depending on box tuning, but the room interaction will swamp this unless the tunings are absurd. If you're using a LT it will compensate for any discrepancy in the box tuning and alter the transient response to your desire.
The only time this changes is around resonance at low frequencies, so you'll get a bit of undershoot or overshoot, depending on box tuning, but the room interaction will swamp this unless the tunings are absurd. If you're using a LT it will compensate for any discrepancy in the box tuning and alter the transient response to your desire.
Hi,
I have desined and built a long time ago a similar 3-way system.
I recall using 10" woofer with rather low VAS, fs ~= 30 Hz and Qts ~=0.45. It worked quite well, so I suggest a woofer should be selected with similar properties if closed box is considered. And closed box can be stuffed with mineral wool which is quite effective at killing standing waves inside the box, unlike regular fiberglass.
Hope this helps and good luck
Regards
I have desined and built a long time ago a similar 3-way system.
I recall using 10" woofer with rather low VAS, fs ~= 30 Hz and Qts ~=0.45. It worked quite well, so I suggest a woofer should be selected with similar properties if closed box is considered. And closed box can be stuffed with mineral wool which is quite effective at killing standing waves inside the box, unlike regular fiberglass.
Hope this helps and good luck
Regards
The only deformation is what is going on in your brain.
Trying to use a driver that has an efficiency bandwidth product of 295.45 hz at 50 hz in a sealed box is absolute insanity. Really.
FWIW, Klippel Verified means nothing really. It means the driver was tested on a Klippel.
I've seen a 'Klippel Verified' driver that had a reported 45.5 mm excursion ' without significant loss of motor strength' as said by the company that failed the cms threshold at around ~ 6mm one way. What do you think the manufactuer chose to publish? Also, it's motor failed the threshold at about 13 mm one way. Claimed mechanical stroke was 90 mm p-p.
I've got fast bass, it hits me at around 1125 feet per second.
The response curve is generated in a 975 liter sealed box. This does NOT state the power handling test was done in a sealed box. All of the companies I am aware of test cone drivers in free-air. The 'power handling' is calculated on the minimum impedance.
B&C rate 2 hours continuous pink noise from Fs-10Fs, and the power is calculated on the minimum impedance in free air.
Step away for a few hours, and a ruckus breaks out over what seemed to be an innocuous topic. There's DIYers for ya -- so passionate-like! 🤣 But I do appreciate the inputs.
My only comment about mass, mid/bass vs bass driver discussion: surely Mms by itself cannot be the sole determinant of driver "speed". The motor system plays a huge part & an adequately powerful one can overcome the inertia of higher Mms, quite possibly outperforming lighter Mms diaphragms with inadequate motors. I also agree that "This is not how music works, the signal doesn't just abruptly cease. Every note/sound played is followed by a natural decay in the recorded signal."
I do want to clarify a few things for further discussion:
My only comment about mass, mid/bass vs bass driver discussion: surely Mms by itself cannot be the sole determinant of driver "speed". The motor system plays a huge part & an adequately powerful one can overcome the inertia of higher Mms, quite possibly outperforming lighter Mms diaphragms with inadequate motors. I also agree that "This is not how music works, the signal doesn't just abruptly cease. Every note/sound played is followed by a natural decay in the recorded signal."
I do want to clarify a few things for further discussion:
My recording/mixing/musician friends all work in popular music. Two of them have stated explicitly that they apply a low filter below 30Hz to every final mix. A pretty steep filter, from what I can gather. "There is really nothing worthwhile down there in 99% of the mixes, so why demand the systems (up & downstream) to handle anything that might cause unnecessary overloads." One of these guys has mixed nearly 60 albums. He says he often likes to mix loudly, close to the level the original music was played at. Peaks are often >100 dB/1m. Currently he sits barely 4' away from each of his older Genelecs.
It's the combination of low Vas (52l) & Fs (26Hz), & high-ish Qts (0.51) that gives the good sealed box bass projections for the Dayton RSS265HF. I think that balance of specs is rare; there have been laments in the past (here and elsewhere) about how hard it is these days to find bass drivers suitable for old school "acoustic suspension". Sensitivity is fairly low though.
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To this statement, I recall that " according to a recent nationwide survey, more doctors smoke Camels than any other cigarette"
Seems absurd doesn't it? If you do a google image search you can certainly find such claims.
Some people like to put hot sauce on everything. Does that mean you should?
A very strong motor can move a heavy mass with great accelerations, but conjecture lives on that only tissue paper weight drivers are capable of 'fast' bass. To this, I say these people have never heard real bass. Like 5-10 hz bass that gives you the sensation that you are underwater, after jumping into the deep end of the pool.
These people must listen to girl with guitar music, never to have experienced Infected Mushroom, real big fireworks displays up close, Nitromethane powered dragsters or the like.
@diyuser2010 -- all I am saying is that my "clients" aren't bothered about accurate deep bass on these monitors. I'm not trying to design a beast of a high end monitor to outdo all others. They need to be accurate within the bandwidth of 35~15k. They are meant to be tools for mixing/monitoring music in studios which are smallish. 12 x 18" with 8~10' ceiling is a fairly typical room size. And yeah, I have heard some heavy bass tracks among their output. They simply don't need or want the last half octave.
Keep in mind this high end ATC SCM50ASL Pro, which sells for CA$21,000/pr, has "Cut-off Frequencies (-6dB, free-standing): 38Hz, 25kHz". They obviously don't think sub-sonics are useful in a studio monitor. https://atc.audio/professional/loudspeakers/scm50a-pro/
They do offer a sub for studio use: Low Frequency Cut-off: 22Hz (-6dB, half space, low pass filter @ 80Hz).
Keep in mind this high end ATC SCM50ASL Pro, which sells for CA$21,000/pr, has "Cut-off Frequencies (-6dB, free-standing): 38Hz, 25kHz". They obviously don't think sub-sonics are useful in a studio monitor. https://atc.audio/professional/loudspeakers/scm50a-pro/
They do offer a sub for studio use: Low Frequency Cut-off: 22Hz (-6dB, half space, low pass filter @ 80Hz).
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There is no such thing as fast bass. Bass is inherently slow as dictated by the speed of sound and the wavelengths involved.
Any perceived speed is coming from the high frequency components.
If a heavy bass driver cone is incapable of moving at a sufficiently high velocity, such as to reproduce a given frequency, then it's frequency response falls off a cliff and no amount of brute force will make it go any higher.
Nobody has heard 5-10Hz bass. Human hearing does not extend that far down. You might be able to feel it but you will not hear it.
A steep 30Hz filter is a very useful and almost universally used tool in the studio. Below that is only non-musical mush which can ruin recordings.
Frequencies below that are only useful in cinema effects and even then they exist only rarely.
In modern music (synthesizers not included) the lowest note is the 38Hz from the open string of a 5 string bass guitar. That said most bassist use 5strings so the 42Hz (lowest on a 4 string) can be fretted which sounds different from playing an open string due to the different harmonics produced.