There doesn't seem to be much consensus on this topic. Some say that you should only pair high sensitivity compression drivers with similarly sensitive drivers. Others say that a good lpad makes compression drivers just as suitable a match as any other tweeter, even to lower sensitivity woofers. What do you think, and why? Or, what have your experiences been?
It is perfectly OK to pair a compression driver with a low dB/W woofer, especially at low power levels. However, the other way is trouble, as there seems to be a lot more energy in the lower frequencies than at HF and an L-pad on the woofer would waste more power as opposed to one on the compression driver.
If you don't want to have to use a subwoofer go lower to say 91/93 dB 1 watt with suitable bass response such as JBL Le-14H or 2235. Drivers used in Array 1400 and 4430. Compression drivers are padded down all the time even with 97/98 dB drivers so I don't understand what consensus you are looking for.
Rob 🙂
Rob 🙂
Indeed, just look at Altec, et al consumer speakers from days gone by, though typically used a high quality pot to fine tune the shelving and nowadays ideally need a bypass cap to let the extreme highs through that weren't in the recordings of the times. Best IME (among many that have 'antique tech' systems) to bi-amp with SET tube for the HF, Class A/B for the woofer to get the best of both 'worlds'.
-it is an active design though:
https://ggntkt.de/en/model-m1/
This is the 6" driver:
https://hificompass.com/en/speakers/measurements/sbacoustics/sb-acoustics-sb17nbac35-8
One of those "technically" perfect speakers that I'd bet sounds (subjectively) sort of "meh". (..excellent design, superb objective behavior in a limited spl range or limited bandwidth.. but likely lacking a bit of that "wow" factor (other than bass extension for a small speaker at lower spl).)
https://ggntkt.de/en/model-m1/
This is the 6" driver:
https://hificompass.com/en/speakers/measurements/sbacoustics/sb-acoustics-sb17nbac35-8
One of those "technically" perfect speakers that I'd bet sounds (subjectively) sort of "meh". (..excellent design, superb objective behavior in a limited spl range or limited bandwidth.. but likely lacking a bit of that "wow" factor (other than bass extension for a small speaker at lower spl).)
Most decent compression drivers are ~108-112 dB/w/m, and I haven't seen woofers, any woofers, that are anywhere near. I've used 111dB compression driver with woofer/arrays 93-95dB sensitive, and the mix works great, as long as overall gain is matched somewhere.
Instead of going by sensitivity numbers, I would pay MUCH more attention to if the woofer(s)/enclosure have enough speed and low enough distortion to mate with CD's.
Yes your right there is little consensus on what is best or what you can and cant do according to the well informed. Best thing about diy is you can follow your own goals,ideas and creat what you want. It all starts with you. The trap for speaker designers who are experts they get stuck in a narrow mind set and everything else is wrong. Thats why jeoff bagby was such a talent he deigned and built speakers that were unique. Eg hellios was way cool.
If you simply go active with good gain staging practice, you can mate anything to anything.
It's not worth wasting thought over ime/imo, .....unless you're into the passive world.
It's not worth wasting thought over ime/imo, .....unless you're into the passive world.
Of course you could, but if you're paranoid about some (hitherto) undocumented disadvantage eating musicality then it may be better to use a small linear amp (< 50W) for the compression driver, along with a series (film) capacitor for DC protection. The value of the capacitor needs to be chosen according to the CD impedance and the cutoff frequency.
In many sound reinforcement setups, the average power on the CD is still less than 100W, so one could imagine how much they'd be using at home, at much smaller listening distances !!
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Still amazed of how a couple of transistors can make such noiz!
And how the elongation of bass in open space differs from home. I do miss the last octave but (cheap)HiFi tweeters Just don't cut for partying...
And how the elongation of bass in open space differs from home. I do miss the last octave but (cheap)HiFi tweeters Just don't cut for partying...
By far the easiest way is to use a good variable Lpad of 20 or 50 Watt rating. (depending on frequency range)
OR :
https://en.wikipedia.org/wiki/Voltage_divider
https://www.aetechron.com/calculator-Volt2dB.shtml
OR :
https://en.wikipedia.org/wiki/Voltage_divider
https://www.aetechron.com/calculator-Volt2dB.shtml
Simple answer is yes.
But it isnt just matching SPL.
For best sound, horn shouldnt cover more than 3-4 octaves above its cutoff frequency. For 20kHz, thats 1250Hz, or lets say 1,2kHz. Crossing point should be at least 1/3 octave above, so around 1,5kHz.
Larger (10in and above) woofers (around) 85dB are either heavy cone subs, or budget drivers with weak motor and high Qts.
In both cases, they wont be suitable above 1kHz and performance will probably be poor above few hundreds Hz.
Smaller woofers (around) 85dB can work well up to 1,5kHz, but max SPL will be very much limited compared to horn.
So, matching the two worlds will be difficult without additional compromises.
