Andy I do believe there are some crossed wires here (pun intended) - this is really very simple. Time and frequency in this context are not the same. An example - you have a pure tone of 50 hz that lasts for 20 seconds. Obviously 50 hz is the frequency and 20 seconds is the time that frequency lasts for - thats all they are talking about here - how long a given frequency lasts for in a speaker when it is no longer present at input - ie the decay time of different frequencies .
Is it audible - the evidence would seem to suggest it definately is - there are many papers in respectable peer reviewed journals that cover this topic that a quick search would show up ,I can remember off hand but I believe the minimum audible change in sound we can hear is very short in the order of 10 ms (obviously loudness dependant and lets not even start on Fletcher/Munsen curves!) - some of the decay times we are talking about here can be longer than 400 ms !
Of course the room is important but what I am saying is all of these things together contribute to our perception of sound and clarity including the decay times of speakers (not just the room !). Personally I like a fairly dead room for mixing and that means I have to consider speakers too.
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This is great info tx a lot - youve definately bought me down to earth ! Someone suggested I could just design a digital crossover in my software (I have plenty of outputs) - is this recomended ? I would probably use max msp for this but anyone have other suggestions for software ? I have an RME raydat soundcard - so I guess maybe they have a facility for putting filters on the outputs - anyone know ? I will peruse later when I have a moment. On the subject of the temporarily postponed tree speaker dream - there seems to be some difference of opinion here as to whether thick wood would be suitable or not (cracking resonance) - anyone got any reference s(preferably from peer review journals !)that sway the argument either way ?
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Oh and one more thing hollow boy (or anyone else) - I need to replace the amp on the tb2s+ - the flying mole things they used to use are no longer available and brystons are expensive as are hypex mono blocks, I am currently using an art sla1 on them - anyone recomend a good cheap amp for them that would do the job or is the art sufficient ? Also if I bi amped them would it make any difference and if so it matter if the amps are the same ?
I am a firm believer in the implications of the Richard Clarke amplifier challenge BTW.....
I am a firm believer in the implications of the Richard Clarke amplifier challenge BTW.....
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Augustine,
The fact you paid 1350 pounds for passive pmc tb2s which contain only 100 pounds worth of drivers does not change my opinion that there are better active systems available for far less money now.
Compare the measured response of Genelec, KRK, or whatever other choices are under consideration to the "kingroy4 thing", and if you think you get a better value when your time is factored in (I have no idea what you value your time at) then go for it.
As far as your desire to go sealed vs ported, that's your choice, but the 10 dB (or more) reduction of output potential will cost dearly to make up for, and since in a small room the room output will dominate any delay issues, that is money that could be better spent elsewhere.
Below is the frequency and phase response of a a Sony 7506 headphone, a 36 Fb ported 2x12" (Lab 12s) and the same cabinet with the ports sealed. As you can see, the phase difference occurs below Fb, if Fb was lowered to 20 Hz, the difference would also be lowered. At any rate, the phase/time difference below 60 Hz would be room dominated, a 60 Hz wave is almost 19 feet long (5.8 meters) and will be reflecting off all your room boundaries with near the same amplitude as the initial transient.
Cheers,
Art
Attachments
tx - I think I get what your saying . I dont have a small room incidently - actually I have a choice of several sized rooms.
Genelec and krk dont make monitors that go down to 25 hz though... genelecs are pricy too - with a sub the system would come in at least £2000. I think Im probably just getting some subs for the tb2s as suggested. Another poster suggested the kingroy4 speaker would give you the performance of a much more expensive speaker (I think he said a 37,000 dollar one) for a fraction the price - would you not agree then ?
If you like point sources, time coherency and have room for them you could try a DIY synergy horn so you also limit room reflections:
http://www.diyaudio.com/forums/multi-way/200539-diy-synergy-horn.html
It is quite complex so might not be suited for a first time build. Search around a bit for other examples.
http://www.diyaudio.com/forums/multi-way/200539-diy-synergy-horn.html
It is quite complex so might not be suited for a first time build. Search around a bit for other examples.
No it is not simple but it is basic and fundamental for those working with sound. You mentioned that you were taught about it in the past but it didn't sink in so you know your teachers thought it relevant. You can see your current knowledge is not wholly aligned with what more senior people with more resources do. You think you may have recently made a poor purchasing decision based on faith in your current set of sources of knowledge. So what is the next move?
Andy - please refrain from ad hominem attacks - if you can refute the point I made , and that is made in much audio literature and in fact by several members of this board, then that's fine - if you cannot - that is also fine - let me repeat it :
and here are quotes from the magazines again (I could dig out some AES journals if you prefer academic sources) :
MONITORS versus HI-FI SPEAKERS
The Yamaha NS10 Story
http://www.resolutionmag.com/pdfs/SWEETS~1/LOWFRE~1.PDF
I may also refer you to a thread right here where several members also expressed the same opinion :
http://www.diyaudio.com/forums/multi-way/21124-question-waterfall-transient-response.html
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Yes- it is hard work. You have to have the right driver, and not many are made that can do that. The Ultimax is a viable option, but I think a larger box may help too.
Are you looking at power efficiency or voltage sensitivity? Since voltage Sensitivity is what we generally use to balance all other factors in term of output, all rated at 2.83VAC, you get a +6dB gain from a pair of drivers in parallel over that of a single.
Now- Another wrench, the Ultimax are DVC woofers, and measured with coils in series due to being dual 2 ohms and most amplifiers liking 4 ohm loads. Using pro-amps that are 2 ohm capable, or even 1 ohm capable, you can increase the voltage sensitivity even higher just by placing the drivers coils in parallel. Of course, this also means that you would have to remeasure the T/S parameters and optimize for that set of data.
I think the Ultimax is an option, but some finagling with the methods can achieve a lot more than just a sealed 4ft^3 box wired in series.
As to the KINGROY4, TAD, and KEF mentioned earlier....
I've heard all three now. ...
The KEF Uni-Q in the Blade I did not care for. The xover needed work, and the bass was very light from the system as a whole. The woofer or tweeter (not certain which) resonance has not been dealt with at all, and sounds very harsh and fatiguing. I bet the drivers are good, and with some xover work would sound much better.
The TAD I was actually kind of disappointed in. I had much higher hopes. Bass was taut, but not very low extended. This is likely because it appeared to be a 10" pro woofer in a cabinet much too small for it to dig very deep. The coax was just 'okay' in terms of clarity, and I would not likely call it analytical. I expected more, and preferred the clarity of the Magico S3 to these. I also think the xover could be improved here to get a better transparency, but the low bass still would likely not happen.
The KINGROY4 I did not get much time with, but I was expecting it to go lower. That woofer is a beast, and I feel a larger cabinet would likely make that great on the low end. The Coax has a very smooth quality to it, and nothing stuck out, but I still wanted more transparency from it. It seemed a bit sterile to me, but some like that. It's likely a good value that can be tweaked if you wish in terms of cabinet size/tuning and maybe M/T level in reference to the woofer.
My 2c,
Wolf
Sorry, being pedantic, but Genelec certainly do. I don't rate KRK much, though.
1236A SAM? Studio Monitor | Genelec.com
Its worth noting that low-frequency group delay is largely considered inaudible, while the extra distortion of running a sealed box hard is definitely audible. I'd choose ported or similar if space was no object.
Chris
Not at all - I stand corrected - however we were talking within the context of "affordable speakers" within the £1000 range and whether its better to go DIY or buy a ready made monitor - I suspect this beast would be in the tens of thousands !
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