Keep in mind the Crown XLS Series of Class-D Amp have built in Crossover and come in a range of sizes. The Crown XLS1502 is 300w/ch but they have more powerful amps.
Product Search - Studiospares
The Crown XLS-2502 has 440w/channel to 8 ohms and an 1550w in Bridged Mono to an 8 ohm load.
Obviously there are hundreds of PA Power Amps to choose from -
Power Amplifiers - Studio Gear - Studiospares
Crown XTi-4002 -650w/ch @ 8ohms - £1250 -
Crown XTi2 4002 Power Amp - Power Amplifiers - Studio Gear - Studiospares
Crown XTi-6002 - 1200w/ch @ 8 ohms - £2299 -
Crown XTi2 6002 Power Amp - Product Detail - Studiospares
How far do you want to take it?
Steve/bluewizard
Product Search - Studiospares
The Crown XLS-2502 has 440w/channel to 8 ohms and an 1550w in Bridged Mono to an 8 ohm load.
Obviously there are hundreds of PA Power Amps to choose from -
Power Amplifiers - Studio Gear - Studiospares
Crown XTi-4002 -650w/ch @ 8ohms - £1250 -
Crown XTi2 4002 Power Amp - Power Amplifiers - Studio Gear - Studiospares
Crown XTi-6002 - 1200w/ch @ 8 ohms - £2299 -
Crown XTi2 6002 Power Amp - Product Detail - Studiospares
How far do you want to take it?
Steve/bluewizard
Though it doesn't fit your design, here are some sketches of a design that I am planning, though as to the delay, I plead poverty -
On the Left is a 3.5-way design with an 8" Mid-Bass and a 10" Low-Bass.
On the right is a straight forward 3-way, with 2x4" Midrange, and a 10" Woofer.
I thought you might find some inspiration from the Trapezoid cabinets. Click on the Photo, the un-clicked version is slightly squashed. The grid on the drawing is 2.5" per square or about 63.5mm.
ConvertIt.com Measurement Converter
Steve/bluewizard
On the Left is a 3.5-way design with an 8" Mid-Bass and a 10" Low-Bass.
On the right is a straight forward 3-way, with 2x4" Midrange, and a 10" Woofer.
I thought you might find some inspiration from the Trapezoid cabinets. Click on the Photo, the un-clicked version is slightly squashed. The grid on the drawing is 2.5" per square or about 63.5mm.
ConvertIt.com Measurement Converter
Steve/bluewizard
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Well, 'til distortion ?
Noo, just kidding. Of course not. Don't really know. I think 1/4 of the whole system's limit is shaking the house already. I just simply like the sound of really big systems, even on low power. It's so different.. spacy.. volume.. dunno. Not easy to describe. I'll need 6 monoblocks. No passive setup for mids and highs, I'd like to keep as much in control as much I can. Max RMS power rating for the bass amp into 4 Ohms is a bigger question than the type of the amp itself (impedance is not far from 4 Ohms on the Dayton, Re=5.6 and at around 100Hz we're back here again so at louder levels it will drain pretty much current from the amp - more than the nominal 8 Ohm so I think in 4 Ohm ratings regarding amp specifications).
Well we're almost in the same shoes (or how do you say it in the US) Nice sketch. My first was like this one here with a side-firing woofer crossed quite low but I just abadoned it..
Now I'm considering your trapezoid way almost exactly but .. I need volume and don't want to grow with the bass box towards the back wall. Instead, I can grow upwards to gain volume with some considerations in mind:
- 1 speaker midrange 10PR320 (10" - 300W - 96 dB - 8 Ohm)
- side view: click
- front view: symmetrical trapezoid base (front: 25.59", back: 29.52", sides: 23.62"),
slightly shrinking trapezoid upwards like in your design.
With parallel walls I'd need about 50" height, with slightly trapezoid walls I need to grow a bit more, not calculated yet. Therefore, a piece for the mid-high section (built into a small box) would be choopped off from the bass box, just 'til the magnets are aligned. This again takes a little volume away. At the end this would be a little nightmare-ish for a carpenter with all these slight angles .. but I think this way I 1) align voice coils vertically 2) separate the mid-high section completely from the bass box resonances.
A simply pyramid growing high and then the top chopped off would look much better, but I try to be precise. That step-like break (corner) in the bass section will not be visible at these bass frequencies by the driver so I don't expect trouble here.
Will it look ugly ? I assume yes. If the prototype will pay off my efforts I'll have that lacquered in white piano finish but 'til then there's plenty of work.
Nice sketch. My first was like this one here with a side-firing woofer crossed quite low but I just abadoned it.. An externally hosted image should be here but it was not working when we last tested it.
Now I'm considering your trapezoid way almost exactly but .. I need volume and don't want to grow with the bass box towards the back wall. Instead, I can grow upwards to gain volume with some considerations in mind:
- 1 speaker midrange 10PR320 (10" - 300W - 96 dB - 8 Ohm)
- side view: click
- front view: symmetrical trapezoid base (front: 25.59", back: 29.52", sides: 23.62"),
slightly shrinking trapezoid upwards like in your design.
With parallel walls I'd need about 50" height, with slightly trapezoid walls I need to grow a bit more, not calculated yet. Therefore, a piece for the mid-high section (built into a small box) would be choopped off from the bass box, just 'til the magnets are aligned. This again takes a little volume away. At the end this would be a little nightmare-ish for a carpenter with all these slight angles .. but I think this way I 1) align voice coils vertically 2) separate the mid-high section completely from the bass box resonances.
A simply pyramid growing high and then the top chopped off would look much better, but I try to be precise. That step-like break (corner) in the bass section will not be visible at these bass frequencies by the driver so I don't expect trouble here.
Will it look ugly ? I assume yes. If the prototype will pay off my efforts I'll have that lacquered in white piano finish but 'til then there's plenty of work.
Btw you're working with smaller drivers, have you ever thought to try a setup like the Status Acoustics Titus 8T ? This inspired me to separate the mid-high section from the bass (although they fix the mid-high's stand to the bass box which brings back some resonances, I will have 2 separate holders for the mid-high box made by one of my friends, neither the small box nor the stand will touch the bass box).
Check out this video. I don't know if all this is BS or makes any sense, but at around 4:15 .. the biggest resonance colouring the midrange's and tweeter's sound just like on this cool animation is the bass box itself so I think it's gererally good if you levitate your mid-high section (no joke, I really thought about magnets too)
Let's do a power analysis. I think you said the system would be about 95dB Sensitivity.
So, let's work out how much power you would need to reach the THX Home Theater Sound Levels, which are 105db for not-subwoofer, and 115db for the Subwoofer.
Here is how the power ramps up -
95db = 1w
98db = 2w
101db = 4w
104db = 8w
107db = 16w
110db = 32w
113db = 64w
116db - 128w
Surprised?
Of course we have to consider distance. Unless I am mistaken, the sound drops -6db every time you double the distance. So the measurements are taken at 1 meter (3.28ft), if we double that to 2m (6.6ft), and double again to 4m (13.12ft), and double one last time to 8 meter (26.3ft)
If you are sitting 13ft/4m away from the speakers, we have this
95db - 12db = 83db = 1w
98db - 12db = 86db = 2w
101db - 12db = 89db = 4w
104db - 12db = 92db = 8w
107db - 12db = 95db = 16w
110db - 12db = 98db = 32w
113db - 12db = 102db = 64w
116db - 12db = 105db =128w
119db - 12db = 108db = 256w
121db - 12db = 111db = 512w
124db - 12db = 114db = 1024w
127db - 12db = 117db = 2048w
If we are at 8m/26.3ft then this -
95db - 18db = 77db = 1w
98db - 18db = 80db = 2w
101db - 18db = 83db = 4w
104db - 18db = 86db = 8w
107db - 18db = 89db = 16w
110db - 18db = 91db = 32w
113db - 18db = 94db = 64w
116db - 18db = 97db =128w
119db - 18db = 100db = 256w
121db - 18db = 103db = 512w
124db - 18db = 106db = 1024w
127db - 18db = 109db = 2048w
130db - 18db = 111db = 4096w
133db - 18db = 113db = 8192w
136db - 18db = 116db = 16384w
Remember the two target peak volumes are 105db for the Front Speakers and 115db for the Subwoofer
The first number on the left is the volume at the speaker (1m), the dB on the right is the volume at the seating location, and on the far right, the power need to reach that volume at the specified seating distance.
These are theoretical numbers, in reality, you don't need that much power, and it is very UNLIKELY that you will be seated 26ft away from the speakers.
I'm not sure how to calculate this for a fixed distance that is not some doubling of 1 meter. Though I'm sure there is a formula for it.
If we use 95db Sensitivity speakers, at a distance of 4m/13ft (-12db) , then it takes 128w to reach 105db, and 1024w to reach 115db for the Sub. These are PEAK values, even when hitting Peaks that high, the average value is going to be substantially lower.
On my system, I've hit +110 dB peaks as measured from 11 feet with no audible distortion using 100w/ch amps (NO Subwoofers) . So, the power rating shown are a bit misleading, but mathematically that is how it works out.
The 105db comes from an average calibration volume of 85db with 20db of headroom for a total of 105db. The Subs are just 10db higher 95db average with 115db peaks.
However, these are extremely loud maximum volumes, rarely to never does anyone hit these volume and if by change they do it is for a very very short period of time. Also, on short term peaks a bit of amp Clipping will go unnoticed.
I would speculate that 100w to 200w on the Mid/High would be sufficient, however, it you want Subwoofer level on the 18" Bass Drivers, you are probably going to need 500w/ch to 1000w/ch amps.
Keep in mind, once again, that 105db and 115db are EXTREMELY Loud. Loud enough that in an industrial setting you would be required by law to have ear protection. Only on the rarest occasion at the loudest volumes would you briefly hit peaks like this.
Many people run the volume on their AVR at about -10db for movie listening. That cuts the power requirements considerable. In this case, we are back close to roughly the 1 Meter numbers I posted above.
You can make a judgement based on the AVR read out dB level you most commonly use.
For what is might be worth.
Steve/bluewizard
So, let's work out how much power you would need to reach the THX Home Theater Sound Levels, which are 105db for not-subwoofer, and 115db for the Subwoofer.
Here is how the power ramps up -
95db = 1w
98db = 2w
101db = 4w
104db = 8w
107db = 16w
110db = 32w
113db = 64w
116db - 128w
Surprised?
Of course we have to consider distance. Unless I am mistaken, the sound drops -6db every time you double the distance. So the measurements are taken at 1 meter (3.28ft), if we double that to 2m (6.6ft), and double again to 4m (13.12ft), and double one last time to 8 meter (26.3ft)
If you are sitting 13ft/4m away from the speakers, we have this
95db - 12db = 83db = 1w
98db - 12db = 86db = 2w
101db - 12db = 89db = 4w
104db - 12db = 92db = 8w
107db - 12db = 95db = 16w
110db - 12db = 98db = 32w
113db - 12db = 102db = 64w
116db - 12db = 105db =128w
119db - 12db = 108db = 256w
121db - 12db = 111db = 512w
124db - 12db = 114db = 1024w
127db - 12db = 117db = 2048w
If we are at 8m/26.3ft then this -
95db - 18db = 77db = 1w
98db - 18db = 80db = 2w
101db - 18db = 83db = 4w
104db - 18db = 86db = 8w
107db - 18db = 89db = 16w
110db - 18db = 91db = 32w
113db - 18db = 94db = 64w
116db - 18db = 97db =128w
119db - 18db = 100db = 256w
121db - 18db = 103db = 512w
124db - 18db = 106db = 1024w
127db - 18db = 109db = 2048w
130db - 18db = 111db = 4096w
133db - 18db = 113db = 8192w
136db - 18db = 116db = 16384w
Remember the two target peak volumes are 105db for the Front Speakers and 115db for the Subwoofer
The first number on the left is the volume at the speaker (1m), the dB on the right is the volume at the seating location, and on the far right, the power need to reach that volume at the specified seating distance.
These are theoretical numbers, in reality, you don't need that much power, and it is very UNLIKELY that you will be seated 26ft away from the speakers.
I'm not sure how to calculate this for a fixed distance that is not some doubling of 1 meter. Though I'm sure there is a formula for it.
If we use 95db Sensitivity speakers, at a distance of 4m/13ft (-12db) , then it takes 128w to reach 105db, and 1024w to reach 115db for the Sub. These are PEAK values, even when hitting Peaks that high, the average value is going to be substantially lower.
On my system, I've hit +110 dB peaks as measured from 11 feet with no audible distortion using 100w/ch amps (NO Subwoofers) . So, the power rating shown are a bit misleading, but mathematically that is how it works out.
The 105db comes from an average calibration volume of 85db with 20db of headroom for a total of 105db. The Subs are just 10db higher 95db average with 115db peaks.
However, these are extremely loud maximum volumes, rarely to never does anyone hit these volume and if by change they do it is for a very very short period of time. Also, on short term peaks a bit of amp Clipping will go unnoticed.
I would speculate that 100w to 200w on the Mid/High would be sufficient, however, it you want Subwoofer level on the 18" Bass Drivers, you are probably going to need 500w/ch to 1000w/ch amps.
Keep in mind, once again, that 105db and 115db are EXTREMELY Loud. Loud enough that in an industrial setting you would be required by law to have ear protection. Only on the rarest occasion at the loudest volumes would you briefly hit peaks like this.
Many people run the volume on their AVR at about -10db for movie listening. That cuts the power requirements considerable. In this case, we are back close to roughly the 1 Meter numbers I posted above.
You can make a judgement based on the AVR read out dB level you most commonly use.
For what is might be worth.
Steve/bluewizard
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Hah excellent.. this calculation would need to go into a separate topic and made sticky Very nice.
Yeah, dB, LOG scale and all that stuff was known to me but I haven't dared to count what power I'll really need here.. yet.. you solved this quickly.
Although I plan to play 80% music on the setup you're right with these THX recommendations: when I watch movies occassionally I expect way different levels and listening style/mindset than with music. And to be honest our cinemas (the big ones by Cinemacity) still lack some bass power sometimes, or the upper part of tweeter range.. I don't like their sound very much. Even IMAX which is certified to whatever standards doesn't satisfy me very much.
What I expect is watching Dunkirk on BluRay and my stereo set places me right into the middle of the battle where my stomach shakes to the sound of the V12 Rolls-Royce Merlins. I don't need surround speakers or that great amazing 360° effect but what's coming out into 2.0 should rip my head off when somebody shoots (e.g. when the Germans shoot holes on the boat waiting for high tide).
Well... yeah. I'm going to enjoy the system from ca. 3-4 meters, yepp. I go for Class D then.
Very nice.Yeah, dB, LOG scale and all that stuff was known to me but I haven't dared to count what power I'll really need here.. yet.. you solved this quickly.
Although I plan to play 80% music on the setup you're right with these THX recommendations: when I watch movies occassionally I expect way different levels and listening style/mindset than with music. And to be honest our cinemas (the big ones by Cinemacity) still lack some bass power sometimes, or the upper part of tweeter range.. I don't like their sound very much. Even IMAX which is certified to whatever standards doesn't satisfy me very much.
What I expect is watching Dunkirk on BluRay and my stereo set places me right into the middle of the battle where my stomach shakes to the sound of the V12 Rolls-Royce Merlins. I don't need surround speakers or that great amazing 360° effect but what's coming out into 2.0 should rip my head off when somebody shoots (e.g. when the Germans shoot holes on the boat waiting for high tide).
Well... yeah. I'm going to enjoy the system from ca. 3-4 meters, yepp. I go for Class D then.
@Vortex, are you using an AVR, if so where do you have the volume set.
If not an AVR, the want is your amps, and where is the volume set?
I have a new amp with a digital volume control marked on a scale of 100. It comes on at 45 and is very quiet at that setting. That's were I used to play on my old amp with an analog volume control. The bulk of the volume on this new amps is around 70% to 80%, though when I go as high as 80%, I'm pretty loud.
By getting some sense of where the volume is set, I can get some sense of the actual power requirement.
Keep in mind that the THX/AVR calibration standard is 85db. That corresponds to 0dB on the volume read out. Though of course, the actual volume is based on the content.
There are some who play movies at 0dB (read out) and above, but that is really loud when the peaks come.
Theoretically to hit 115db at a common distance, you need 1024w, but realistically anything 250w and above will get the job done.
If you are using PA amps (Crown and similar), they are pretty cheap. You should be able to get 200w/ch to 300w/ch for the man Front Speakers, and for the 18" Low-Bass, I think roughly 500w/ch amps would be sufficient, though you are free to get more.
Steve/bluewizard
If not an AVR, the want is your amps, and where is the volume set?
I have a new amp with a digital volume control marked on a scale of 100. It comes on at 45 and is very quiet at that setting. That's were I used to play on my old amp with an analog volume control. The bulk of the volume on this new amps is around 70% to 80%, though when I go as high as 80%, I'm pretty loud.
By getting some sense of where the volume is set, I can get some sense of the actual power requirement.
Keep in mind that the THX/AVR calibration standard is 85db. That corresponds to 0dB on the volume read out. Though of course, the actual volume is based on the content.
There are some who play movies at 0dB (read out) and above, but that is really loud when the peaks come.
Theoretically to hit 115db at a common distance, you need 1024w, but realistically anything 250w and above will get the job done.
If you are using PA amps (Crown and similar), they are pretty cheap. You should be able to get 200w/ch to 300w/ch for the man Front Speakers, and for the 18" Low-Bass, I think roughly 500w/ch amps would be sufficient, though you are free to get more.
Steve/bluewizard
I sold my complete gear couple of months ago, my Onkyo went to my mother.. I'm going all DIY, amps too, all six.
My future is a custom passive preamp (no gain stage).
- Line IN 1, the output from the DAC: I'll set my volume on the DAC when I'm ready with all this hardware stuff. Signal then goes directly to the active filter inside the preamp box and from there to the speakers' amps.
- Line IN 2, the output of the phono MC preamp: goes through a 256-step relay based volume attenuator and from there to the active filter.
I don't think I'll calibrate to any standard. Just take the Omnimic, measure and take care of a somewhat flat and acceptable freq. curve across the whole audio spectrum. Not sure yet if I'll correct room issues at all or leave as is. For room correction either computer would be needed (do it fully digitally) or DSP which does an extra analog-digital and then digital-analog conversion which I don't need I think, when I have a high resolving DAC in front of that. But this will be future, not decided yet. Probably I'm better with a corrected room, DSP and lower resolutions than uncorrected with a high-end DAC. I'll try both.
My future is a custom passive preamp (no gain stage).
- Line IN 1, the output from the DAC: I'll set my volume on the DAC when I'm ready with all this hardware stuff. Signal then goes directly to the active filter inside the preamp box and from there to the speakers' amps.
- Line IN 2, the output of the phono MC preamp: goes through a 256-step relay based volume attenuator and from there to the active filter.
I don't think I'll calibrate to any standard. Just take the Omnimic, measure and take care of a somewhat flat and acceptable freq. curve across the whole audio spectrum. Not sure yet if I'll correct room issues at all or leave as is. For room correction either computer would be needed (do it fully digitally) or DSP which does an extra analog-digital and then digital-analog conversion which I don't need I think, when I have a high resolving DAC in front of that. But this will be future, not decided yet. Probably I'm better with a corrected room, DSP and lower resolutions than uncorrected with a high-end DAC. I'll try both.
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Kevinkr, I'm a fan of your posts and respect your opinions. If you don't mind, and if it isn't too off-topic, can you please say what your speaker system is? Thanks!
No you don't, you might need Monoblocks on the 18" bass drivers, but not on the Mid/High.
The Crown XLS-1502 are 300w/channel in Stereo, but are 1050w in Bridge Mono to 8 ohms and 1550w to 4 ohms.
Crown XLS 1502 Drivecore Power Amp - Power Amplifiers - Studio Gear - Studiospares
The price in the UK is £475 (€535) each. So you would need FOUR for a total cost of £1900 or €2140. (2x Stereo-Mid/High, 2x Mono-Low-Bass).
The Dayton Audio PA460-8 is rated at 8 ohms. It is common for the Re to be about 75% of the nominal Impedance Rating.
Keep in mind the Crown Amps have built in Crossovers, so you could start with them in the design process, then when you have proof of concept, disable the internal Crossovers and use the DSP devices you were planning to use. Keep in mind those DSP devices are not going to be cheap.
Here are a couple of Speaker Management systems, that give you much more control than a typical PA Crossover -
dbx Driverack PA2 Speaker Management System - PA Systems - Headphones & Speakers - Studiospares
ART SMS226 Speaker Management System - Monitor Controllers - Headphones & Speakers - Studiospares
These devices and similar device also seem to have Room Auto EQ as well as Crossover Feature, and they have Compression to control peak volume levels.
Here are standard Analog PA Crossovers -
Behringer Super-X Pro CX3400 Crossover - Crossovers - Studio Gear - Studiospares
DBX 234xs 2/3/4 Way Crossover - Crossovers - Studio Gear - Studiospares
They are cheap enough but they are locked at 24dB/Octave crossover slopes. 12dB/Octave are more common in Hi-Fi.
But starting with the Crossovers in the Amps could save you £800 or more in the beginning. Then once you have the Crossovers worked out, and are sure of the system, you could move on to more complex DSP Devices. NOTE: Like a PA Crossover, the XLS-1502 is fixed at 24dB/Octave, but it is a start.
Just a thought.
Steve/bluewizard
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Hi Gentlemen.. also from the "16Hz TL" builder thread..
Quick refresh for "newcomers": I'm planning a 3-way active living room stereo system, 24dB/oct filter, 1st XO at 125Hz (might shift to 150Hz depending on my listening tests with a DSP first). Bass drivers are chosen, the 18" Dayton Audio PA460-8 ones (1 per side).
1. I really like these Daytons. Is it normal that after putting in all parameters into WinISD for a vented box of the same volume (430L/26240in^3/15.18ft^3) it performs very much the same like the 21" RCF LF21X451 monster ? Both tuned at their fs of 28.3Hz (Dayton) and 28.00Hz (RCF) respectively. The freq-SPL curve's lines are just covering eachother almost exactly (1dB +/- here and there but mostly fully the same). Is this 18" Dayton soo "good" or the 21" RCF so "bad" or they just simply behave the same way at this vented box volume ? Apart of maximum power, the PA460-8 is rated at 500W RMS while the RCF LF21X451 at 2000W RMS.
2. Is the 1/24th octave smoothing a "risk" in case of the Dayton's freq. response graph ? (This might hide big anomalies - I don't know if they exist at all or not). Apparently the RFC has less smoothing so the manufacturer is somewhat more "honest" regarding specs however the Dayton starts "earlier", showing quite some more dBs compared to the RCF at low frequencies (which doesn't play much role when put into the box.. just saying as an interesting observation regarding the freq. curve).
3. Is it worth to consider a (folded) TL box for my needs ? I rather need a very great and balanced sounding woofer than a SPL record breaker. I long listened to all of my music with a spectrum analyzer and I don't even need 20Hz-ish VLFs.. I'm fine with my (now) -3dB point of 25Hz. I don't need the RCF's power either, the 500W Daytons would shake the house too, probably. I'm rather striving for "beautiful sound" whatever this means (i would call it audiophile grade bass but I hate this word so I won't).
4. Is it worth DSPing the (always most-problematic) bass section according to final room measurements ? Does it involve much delay compared to a non-DSP-ed mid and tweeter section ? I don't really know if I want to apply DSP and room correction to all 3 ways completely, however, today's DSP resolutions (DAC capabilities) of 24bit/96kHz would be enough for me.
Quick refresh for "newcomers": I'm planning a 3-way active living room stereo system, 24dB/oct filter, 1st XO at 125Hz (might shift to 150Hz depending on my listening tests with a DSP first). Bass drivers are chosen, the 18" Dayton Audio PA460-8 ones (1 per side).
1. I really like these Daytons. Is it normal that after putting in all parameters into WinISD for a vented box of the same volume (430L/26240in^3/15.18ft^3) it performs very much the same like the 21" RCF LF21X451 monster ? Both tuned at their fs of 28.3Hz (Dayton) and 28.00Hz (RCF) respectively. The freq-SPL curve's lines are just covering eachother almost exactly (1dB +/- here and there but mostly fully the same). Is this 18" Dayton soo "good" or the 21" RCF so "bad" or they just simply behave the same way at this vented box volume ? Apart of maximum power, the PA460-8 is rated at 500W RMS while the RCF LF21X451 at 2000W RMS.
2. Is the 1/24th octave smoothing a "risk" in case of the Dayton's freq. response graph ? (This might hide big anomalies - I don't know if they exist at all or not). Apparently the RFC has less smoothing so the manufacturer is somewhat more "honest" regarding specs however the Dayton starts "earlier", showing quite some more dBs compared to the RCF at low frequencies (which doesn't play much role when put into the box.. just saying as an interesting observation regarding the freq. curve).
3. Is it worth to consider a (folded) TL box for my needs ? I rather need a very great and balanced sounding woofer than a SPL record breaker. I long listened to all of my music with a spectrum analyzer and I don't even need 20Hz-ish VLFs.. I'm fine with my (now) -3dB point of 25Hz. I don't need the RCF's power either, the 500W Daytons would shake the house too, probably. I'm rather striving for "beautiful sound" whatever this means (i would call it audiophile grade bass but I hate this word so I won't).
4. Is it worth DSPing the (always most-problematic) bass section according to final room measurements ? Does it involve much delay compared to a non-DSP-ed mid and tweeter section ? I don't really know if I want to apply DSP and room correction to all 3 ways completely, however, today's DSP resolutions (DAC capabilities) of 24bit/96kHz would be enough for me.
Hi Steve,
now some weeks have passed.. I just re-read your comment and aiming for this setup above, regarding listening distance. My selection of amps are also forming:
- Hypex UcD2k Class D (~1250W into 8 Ohm) for bass
- DIY Class AB parallel pushpull tube amps (KT120) for midranges, ~150W into 8 Ohm
- DIY Class AB Exicon lateral mosfet based amps for the tweeter, ~100W into 8 Ohm
I wonder if the big Hypex Class D is needed at all for the woofer or am I good with the somewhat smaller UcD700HG, ~350W into 8 Ohm.
Sensitivities, in the box:
- bass: 95dB
- mids: 95dB
- tweeter: 98dB
For music
For a balanced sound and flat SPL in theory, measured free-air, I'd need the same amount of amp power for bass and midrange and about half of this power for tweeters. I mean actual power, not maximum.
This means: if I choose the big Hypex for bass, I'll most probably have to turn it's volume pretty much down to arrive to midrange amp ~150W levels. Some reserve is always good to have, but that much for bass is insane I think, how do you see it ? The 350W Hypex would be better I think (700W into 4 Ohm, 350 into 8). This would also need the volume turned down to match midrange section but at least the amp would have a headroom of +3dB/2x power if needed, for peaks, and wouldn't run out of current/voltage). Bass is 500W RMS capable so it will handle all this stuff easily.
For home theater:
Big Hypex, increased bass section volume (via DSP/amp gain control/EQ) but woofer's 500W RMS is limiting the game then, pretty soon. Except when I don't aim for THX power levels at 4m (or I'm closer to them). Alternative option for the very same box with a little different port tuning is a 21" RCF which behaves the same way like my chosen 18" bass but the RCF can handle 2000W RMS.
Am I right with all that above ? (Approximately).
However I don't know if I'm going to watch movies on full home theater power at all. Most probably not.
Normally bass is behaving like flat (simulation!) from 30Hz and above. Analyzing the SPL curve to the left:
-3dB at 25Hz
-6dB at 23Hz
hitting 20Hz with 84dB SPL (-11 from 95dB)
PA stuff, not dedicated subs but it would be enough for me going down this deep with this slope, I'm a music guy not a movie/sub-guy. Just playing with numbers now.
Still staying flat: when I apply some EQ for movies, turning the bass section's bottom end into a sub-like behavior, I'd have to bring up this 20Hz extreme with ~11dB, but count with +10dB for easier math
and we're at ~10x power need when an imperial star destroyer swims into the picture in a Star Wars movie and space is shaking, right ? Just to bring 20Hz SPL onto 30Hz SPL levels, nothing more. Just to stay flat compared to midrange. EQ/DSP for the very bottom section only, between 20Hz-30Hz ('cause from 30Hz and up we're natively at 95dB SPL).
Bass equalized so far. For music (or whatever else). At THX-midrange spec. it means 105db/128W down until 30Hz and 1280W is consumed when space is shaking at 20Hz. Right ?
When I take your numbers and aim for THX levels for bass section, I should add another 8x multiplier factor for bass only, right ?
This would mean a whopping ~10kW for the 20Hz region and decreasing back onto 1280W at 30Hz and upwards, if I'm correct. Still pure math, no room effect whatsoever. When I analyze with a measurement mic my room I might gain some bass with proper placement so I spare some watts for some freqs but definitely not for 20Hz. So to sum up my calculations:
- for music at THX spec. and no EQ/DSP for 20Hz lift, I'm good with 500W RMS Dayton bass 'til pretty decent SPL at 13ft/4m.
- for movies at THX spec and no EQ/DSP for 20Hz lift (but EQ for bass/sub overall), I'm weak with 500W RMS bass, 1024W is needed.
- for music at THX spec. with EQ/DSP for 20Hz lift, I'm weak with 500W RMS Dayton bass 'til pretty decent SPL at 13ft/4m, 1280W would be needed (at 20Hz without clipping and woofer damage). Dayton weak, RCF still good.
- for movies at THX spec. with EQ/DSP for 20Hz lift and additional overall bass lift for sub region, I'm weak with both drivers, 10 Kilowatts would be needed (lol) at 20Hz at full THX power.
Wrong, right ? Just in theory, numbers' play, free air, etc.
Can you confirm ?
Alternative solution would be: I choose lower fs, lower Qts bass driver (also lower sensitivity however, most probably) and balance this way to achieve THX power for 20Hz, maybe also doubling them to gain +6 db SPL. Luckily I'm not shooting for this, I'm really not interested in instane stuff, the original setup is big already and I'm primarily listening to music at human levels, not maxing out the system every time.
For low-moderate levels I'll be fine with 20Hz liftup + with movie-mode overall bass lift even at 20Hz with the Dayton's 500W .
Edit: my tweeters wouldn't last long with 128W at 4m listening distance anyway, they're rated at 100W, crossed lower, but still.. pretty much at limit. However, I'll sit at 3m most probably so a -9dB list applies instead of a -12dB one. Woo-hoo. Nooo. I'm not going up 'til THX levels. Just don't need it
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If I may add, I think you may be confusing "maximum power output" with "amplifier gain".
Assuming that your drivers are all the same efficiency, then you will end up matching the amplifier gain across all three drivers, HOWEVER, the power required will be different, as the largest amount of power required will be in the bass, not in the midrange or tweeter...
Assuming that your drivers are all the same efficiency, then you will end up matching the amplifier gain across all three drivers, HOWEVER, the power required will be different, as the largest amount of power required will be in the bass, not in the midrange or tweeter...
Not sure I get the point of your message. I understand it and agree completely and I also plan accordingly, see my class D plans for bass (that's not the only reason I chose class D for the bass instead of AB mosfet or tubes).
For a given SPL, at the same impedance, same sensitivity, same voltage amplification (same gain setting) the same amount of current will be drawn from the amplifier by a tweeter and a bass unit, at least when signals are identical. So for example a sine wave at 20Hz near max signal level on the spectrum analyzer and a sine wave at 20kHz again near max signal level will mean their amps consume the same amount of power 'cause the amount of voltage amplification is the same which at the same impedance draws the same current from the amp and power is determined by these. So at the end both are consuming the same.
If I have a +3dB more sensitive tweeter, I achieve the same with a tweeter amp at 1/2 power needed, compared to bass.
It's the nature of music why tweeters and mids don't play (and don't need) that much energy, but on gain side same sensitivities mean you have to have the same amplification gain on all of your amps, either matched via pots or if there's no pot on them, just making sure they amplify the same amount of voltage on the same input signal (if they're a different make). They can have less max power capability but if this occurs that band might clip and distort of course.
This is what happens in a passive system too, where 1 amp is driving the 3 ways. The nature of music (and sound) determines how much energy will go into which way and this is determined by the input signal. For normal program material biggest signals are in the bass region, then midrange, then tweeter so overall of course tweeter amp will consume less than woofer amp but the ratio at which tweeter is amplifying input signal level to produce the same SPL like woofer for that signal level must be the same and this is gain.
In my case due to 2x tweeter sensitivity I need half the power at whatever volume setting to produce the same amplification so my required gain will be significantly lower here too. At least when talking about gain this is the recipe. Less gain, less power consumption and if we talk about THX cert. levels which are pretty high I just wanted to know the required stable power (near-max power) where amplifiers don't clip and drivers are still able to handle the thing.
The input signal will then take care of how much energy is consumed by which amp, most of it by bass, of course. But if I don't match gains vs. sensitivities I might have a too bright sounding system because of my tweeter (assumed I leave gains untouched).
Btw I made this setup by intention with sensitivities close to eachother so I can use 1 stereo amp and a passive filter while building the amp modules. It takes time to finish all 6.
I tried not to confuse maximum power with needed gain here but they still correlate, for sure I have to be prepared for heavy bass consumption compared to tweeter when I look onto the spectrum analyzer: no tweeter-range signal has that amount of energy like woofer-range signal. However if I would generate a wave file with a near-maximum signal (!!) at 10-20kHz and play it, tweeter amp would just consume the same like woofer amp and burn energy like hell.
I understand the fact that low frequencies need more power to be able to move an exponentially larger amoun of air as we go down towards 0Hz (in theory) but this phenomena is described by the driver's frequency curve (SPL vs frequency at 1m at 2.83V input voltage with 8 Ohm load). As long as the curve says 30Hz: 95dB and then 90Hz: again 95dB, then I go to tweeter datasheet and see 10kHz: 95dB, it's all meaning the same current drawn and the same power is needed for this action by both drivers. Falling SPL curve, 20Hz 85dB only ? A 10x power is needed to compensate, or if this would be a separate amp: a much higher gain setting for 20Hz. And a much bigger, stronger circuit, power supply, etc. to be able to deliver those watts, that's why I think in maximums too, to avoid clipping.. just to get a feeling what might be needed where, especially if I do EQ or compensation on the input signal.
I hope I got your point. Correct me if not. And again, I agree with what you've written.
For a given SPL, at the same impedance, same sensitivity, same voltage amplification (same gain setting) the same amount of current will be drawn from the amplifier by a tweeter and a bass unit, at least when signals are identical. So for example a sine wave at 20Hz near max signal level on the spectrum analyzer and a sine wave at 20kHz again near max signal level will mean their amps consume the same amount of power 'cause the amount of voltage amplification is the same which at the same impedance draws the same current from the amp and power is determined by these. So at the end both are consuming the same.
If I have a +3dB more sensitive tweeter, I achieve the same with a tweeter amp at 1/2 power needed, compared to bass.
It's the nature of music why tweeters and mids don't play (and don't need) that much energy, but on gain side same sensitivities mean you have to have the same amplification gain on all of your amps, either matched via pots or if there's no pot on them, just making sure they amplify the same amount of voltage on the same input signal (if they're a different make). They can have less max power capability but if this occurs that band might clip and distort of course.
This is what happens in a passive system too, where 1 amp is driving the 3 ways. The nature of music (and sound) determines how much energy will go into which way and this is determined by the input signal. For normal program material biggest signals are in the bass region, then midrange, then tweeter so overall of course tweeter amp will consume less than woofer amp but the ratio at which tweeter is amplifying input signal level to produce the same SPL like woofer for that signal level must be the same and this is gain.
In my case due to 2x tweeter sensitivity I need half the power at whatever volume setting to produce the same amplification so my required gain will be significantly lower here too. At least when talking about gain this is the recipe. Less gain, less power consumption and if we talk about THX cert. levels which are pretty high I just wanted to know the required stable power (near-max power) where amplifiers don't clip and drivers are still able to handle the thing.
The input signal will then take care of how much energy is consumed by which amp, most of it by bass, of course. But if I don't match gains vs. sensitivities I might have a too bright sounding system because of my tweeter (assumed I leave gains untouched).
Btw I made this setup by intention with sensitivities close to eachother so I can use 1 stereo amp and a passive filter while building the amp modules. It takes time to finish all 6.
I tried not to confuse maximum power with needed gain here but they still correlate, for sure I have to be prepared for heavy bass consumption compared to tweeter when I look onto the spectrum analyzer: no tweeter-range signal has that amount of energy like woofer-range signal. However if I would generate a wave file with a near-maximum signal (!!) at 10-20kHz and play it, tweeter amp would just consume the same like woofer amp and burn energy like hell.
I understand the fact that low frequencies need more power to be able to move an exponentially larger amoun of air as we go down towards 0Hz (in theory) but this phenomena is described by the driver's frequency curve (SPL vs frequency at 1m at 2.83V input voltage with 8 Ohm load). As long as the curve says 30Hz: 95dB and then 90Hz: again 95dB, then I go to tweeter datasheet and see 10kHz: 95dB, it's all meaning the same current drawn and the same power is needed for this action by both drivers. Falling SPL curve, 20Hz 85dB only ? A 10x power is needed to compensate, or if this would be a separate amp: a much higher gain setting for 20Hz. And a much bigger, stronger circuit, power supply, etc. to be able to deliver those watts, that's why I think in maximums too, to avoid clipping.. just to get a feeling what might be needed where, especially if I do EQ or compensation on the input signal.
I hope I got your point.
Correct me if not. And again, I agree with what you've written.- Status
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