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I recently purchased a sub to augment my Wharfdale Denton stand mount speakers. It is a Martin Logan sub that the lowest crossover point is 40hz.I know this is room dependent but where would be a good starting point to set the sub at? The Denton 80th aniv. specs say they go down to 44hz +\- 3db. Thanks for your help...
Follow Ups:
Start at 80Hz.
never tried them myself, and wonder if lousy rubber footers under subs could be improved on.
mahalo
You have to try both hard and soft for both subs and main speakers. The best is hard for both but if you have an acoustical feedback situation soft with their decoupling(hard couples) then soft may give better sound.
nt
Nt
a meal that you would "spice" with salt and pepper etc. You'd make that meal taste the way YOU like it. So for your sub set it until it sounds good to you. Use various recordings of genres you like. Remember though bass and everything else can vary widely between recordings.
Sure you could get an SPL meter and use test tones but ultimately you should set it how it sounds good to you. Placement of the sub means a lot too.
Enjoy the journey...
E
T
I would probably start at 50 hz. and experiment in the sub's 40-60 hz. range. For me, the x-over freq. issue has always been easier to tune than the sub's input or volume. I go thru a lot of material in search of the happy median..... as I'm not about to hop up and tune the sub every time I change a record, CD, etc.
First, it sounds better than the crossover included with the sub. Second, I keep my gear at arm's reach so there is a subwoofer level control at my fingertips. I don't use the control often but is sure is nice to be able to make slight adjustments from my listening position.
-reub
Regarding placement- In my old listening room (pictured above), I lucked out in that each sub (mono pair) sat right beside each main speaker. Good (but not exceptional) room treatments helped as well. Subs went down to the power amp's built in cut-off; 25hz).
Cut to now- while I don't have a pic to show you, the room is a totally different size and shape! With the subs in the same position as shown above, the "room of boom" happened- great for home theatre, not so good for real music playback. I ended up with BOTH subs (running in mono, of course!) placed at the inside of the right speaker. Boom is gone, but they don't reach quite as low (the room just won't support lower than 30-35hz). Glad it's only a temporary place to live (for the next year or two)...
So, to sum up what everyone else has said- experimentation is the rule to start with, combined with a decent SPL meter and some test tones!
Good luck, and let us know what happens!
Cheers,
Dman
Analog Junkie
If you have switchable options, you don't need to ask questions; you need to experiment. Use the setting that sounds best to you regardless of what anyone tells you. My subs are set to 80-Hz and I hear nothing but deep bass from them -- boom, boom, boom. When I had them set to 60-Hz there seemed to be a gap. At 80-Hz they seem to blend seamlessly with my main speakers. You have to find the setting and location in your listening room that sounds best to you.
I have always liked my subs located behind my listening position against a back wall or in corners. You have to experiment to find out what sounds best to you. Sometimes two subs sound better than one. I could not find a position in my present listening room where two sounded better than one, so I located both of my subs together against a wall behind my listening position approximately the same distance from my ears as the speakers in front. Everything including deep bass sounds like its coming from my main speakers. You need to experiment to find the best location for your sub.
Good luck,
John Elison
With a disc (or download) of at least 1/3 octave warble or pure sinewave tones, you can set the RatShack or similar SPL meter (C-weighted, fast response) at your normal listening position and determine the -6dB frequency of your Wharfedales. Then you can dial in the -6dB corner frequency of the lowpass filter on your sub to that frequency. Measure again and adjust (by ear, as well) until they sum smoothly.
WARNING: this method may also reveal LF room anomalies that can drive you nuts, leading to an endless neurosis with rearranging furniture, installing bass traps, etc.
This is the only method that kept me from going totally nuts when setting up my sub.
Good advice.
My room has a strong mode right around 80Hz, with a +7dB peak measured at the listening position, and moving the speakers around does little to alleviate it.
My power amp driving the main speakers has a 100 kOhm input impedance, so I highpassed it at line level, after the preamp, with a .022 uF series capacitor and a 100 kOhm shunt resistor, resulting in a -6dB electrical transfer function at 85 Hz. This flattens the hump nicely, and pushes the actual measured in-room acoustic -6dB corner down to 64 Hz. I then set the -6dB point on the sub amp to this frequency, and everything blends real nice.
I have another HUGE room mode at 25Hz, but very little music goes this low, so it's rarely a problem. Some organ and synth tracks, though, set the all doors and windows to rattling. Bass traps active at this frequency would be large and expensive, so I'm eventually looking at putting a parametric EQ on the sub to notch it out.
I would start with that lowest setting, especially since it seems you have only one sub. While it's true that bass is omnidirectional below 80 hz, the low pass crossovers are not of the brickwall variety. With my subs set at 50 hz using a 12 db/octave sloped, there is still significant output at twice that frequency. Yours may offer a steeper 24 db/octave slope.
You should experiment with both level and placement since rooms are different and you are trying to blend them with your speakers. Ideally, it will only be perceptible with content that truly has first octave response - think pipe organ, concert / Taiko drums, synthesized bass, etc.
Good luck with your new purchase!
E-Stat is right. 50Hz is very low but 12db/octave is very shallow of a slope. One thing you can do is use a separate outboard 24db/octave crossover if your sub only has 12db/octave. Then you crank the crossover on the sub to "max" (180, 220, etc.) to effectively get it out of the way. Basically, if you have a 50Hz crossover point, your 2nd order "sub amp" crossover filter will kick in two octaves later..., or at 24+24 = 48db down from the 4th order filter. I've done this with good success.
The other way is to set the internal 2nd order crossover to 50Hz, and then use a *second* 2nd order crossover at the same frequency for a net 4th order electric transfer function. Assuming your sub is flat out to 200 or so cycles, this is exactly what you want.
Cheers,
Presto
I actually have three of these powered subwoofers, two of which are in the HT and the other in the garage system. The HT application works fine because I use them in stereo matched with smallish standmounts where they blend very well.
With the Acoustats in the garage, however, I would like a steeper slope for the lone unit. I use the line level input and have gobs of gain. Would buying this provide that 24 db/octave slope mentioned in your second scenario?
Thanks!
If the crossovers are both 12db/octave 2nd order and have the same Fc (crossover point) then they will add to 24db.
Thing is, I can't say how those inline ones work... if they are PLL (Passive Line Level) crossovers they would theoretically need to know the input impedance of the amp. Perhaps car "head units" for which these are designed have a typical input impedance. If the input impedance of your amp is different (or too different) from their design it COULD result in a shift in the Fc from what is advertised.
Yeah, I've never worked with these. It could work in theory but I don't have enough info to even hazard a guess, unfortunately.
Cheers,
Presto
I think I'll wager a try at $35 delivered. I'll post my results. :)
Looking forward to it!
Cheers,
Presto
Partsexpress was fast.
Plugged it in and, presto (pun intended) there was less upper bass content. I can now run the sub level higher for a more linear blend with the stats.
Thanks again!
E-stat:
That's awesome! Big difference that extra 12db/octave makes hey? I find 12db/octave nearly useless... 18 is better but I don't even bother with anything less than 4th order these days... and that's with xo points between 50 and 65hz. How guys run 80 or 90 with 2nd order slopes is beyond me - the localization of the sub alone would be enough to drive me batty.
Glad it worked out! :)
Cheers,
Presto
should have it mid next week.
ONLY hangup is RS meter is NOT 'flat'. At least the analogue meter isn't. And for the price, I doubt the digital is, either.
The RIVES disc is calibrated TO the RS analogue meter.
Too much is never enough
ONLY hangup is RS meter is NOT 'flat'.
While that's true, correction curves are available and the error rate at the bottom isn't huge.
I think RIVES is gone, right?
The disc from RIves is inverse curve of the meter's roll-off, so flat IS flat.
How are the curves available online generated? If more than one, are they in substantial agreement? Just curious since I'd heard (sheer rumor) that the RS meter was like 10db or more low at 30 hz or so. Exact # escapes me, since I was hardly paying attention THAN.
Too much is never enough
How are the curves available online generated?
I'll think you'll find they are comparisons of RS results vs. that of quality calibrated meter.
Just curious since I'd heard (sheer rumor) that the RS meter was like 10db or more low at 30 hz or so.
I'm pretty positive that's not the case having used the curves in the spreadsheet link I provided.
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