For home use, and that is always the point of view that I am taking when I write, I don't think that any CDr that I know of would not be "comfy" at 1000 Hz. I take a 1", fairly small B&C driver down to 800 Hz (De25, DE250, DE500). with no problem at all. There may be some poor quality CDrs out there that are as you say, but none of the higher end companies have that problem.
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I think it's worth noting that any decent driver with a titanium diaphragm will tell you it's struggling well before anything bad happens. Even hammering against the phase plug is okay for a short while.
A lot of the rules-of-thumb about how low a compression driver can safely go are from the PA world where every dB counts. For home HiFi, a lot of those rules simply won't apply.
Now, that doesn't necessarily mean you can run a 1" driver down to 100Hz. You still have to consider that it's a 2" diaphragm with 1mm of Xmax, and that's always gonna put limits on things. It'll still manage 95dB at 400Hz without a horn, though. With a horn to "focus" the output down to a specified coverage area (say, 90x90 degrees, which is still wide dispersion), a smidge over 110dB is possible.
Make it 90x45, and you can add about 6dB for that, and we're starting to get towards PA SPLs again.
Granted, this is very much running at the ragged edge, but 110dB peaks are very loud in a domestic-sized room.
Chris
110dB peak at 1 meter should be around 75dB SPL (RMS) at 6 meter, which is already -10dB less than THX reference level. I don't consider it's very loud...
^that applies only to open air conditions and a single speaker. In a room we have reflections and how many sit at 6m (20ft) distance?
Probably less than 3%, based on a survey of 65 rooms (heavily biased to US responses)...
https://www.diyaudio.com/forums/roo...616-survey-listening-sizes-3.html#post4773079
Chris
We're talking about single speaker. I think it's a horrible sounding room if the room does really affect the overall SPL level a lot...
Aren't these last few posts kind of irrelevant since the 110 dB claim was for a 1" CDr at 400 Hz - something that no one is ever going to do.
35dB level drop in 2,5 times doubling of the distance is incorrect.
The level drop will be, in freefield conditions, 20 x log10 1/6= 16dB, so 110 at 1m becomes 94 at 6m
Edit; now I see you mention peak and rms, so what you are saying is correct if the crest factor is 19dB ( a bit much i think, only applicable for classical and some jazz)
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There's definitely a possibility that my distortion measurements aren't reliable. I've consistently noticed that I'm getting different results from ARTA and HolmImpulse.
I was listening to Kevin Voeck's new speaker, and I listened to it back-to-back with the JBL 4367. The latter used a JBL D2 compression driver on a horn, and the former uses a dome tweeter on a waveguide. I made a comment that the Revel seemed remarkably dynamic, almost as dynamic as the 4367, and Voecks quickly corrected me 🙂
Even though he designed the speaker I was listening to, he seemed a bit shocked that I'd compare it to the 4367.
Having said that, Revel beat the JBL M2 in a recent showdown over at AVS forum.
I think so. The healthy masters of pop music has the crest factor of around 15dB. 20dB headroom is THX reference.
No one seems to have mentioned one obvious drawback of the horn in this thread.
Time alignment. It is challenging to handle without digital processor.
Time alignment. It is challenging to handle without digital processor.
My own bias is to put my faith in the results obtained by ARTA-STEPS ( though I really should dust-off my licensed copy and perform an A-B comparison to REW ).
🙂
I use the B&C DE-25 at home on a 400Hz tractrix horn. It sounds really good and I will never go back to domes again. But I still dont understand many of you suggest using these driveres below 1500Hz, every time I try that, the driver starts sounding thin with no body on voices almost harsh. I have tryed both passive and active filters, right now I use a miniDSP with 24dB linkwitx Riliey slopes, It works the best so fare. Guerilla if you are in the middle of jutland you are welcome for a listen.
This is exactly what happens actually. The crossover delays the lows and the HF driver is behind the woofer, so, in my systems, the two are aligned almost perfectly. Some crossover adjustments and they sum just right.
Im in Aalborg but sometimes visit my brother in Copenhagen, So that would be fun and educating to make a stop on the way thank you🙂
My only crossover is analog so I cant delay with it. I dont have a cd(r) but might get one in the future
I think that you missed my point. An analog LP filter has delay. If I measure the woofer and tweeter without a filter then the impulse are not aligned, but after passing through the filters they are. The woofer gets delayed to exactly match the tweeter because the tweeter is behind the woofer.
Doesn’t the filter introduce phase, and not delay?
And the two can be in phase at the crossover point.
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