The whole point of posting in any forum is to offer an opinion. I think Dingus can reply for himself...

I am sure he can, but as a moderator on this forum I try to keep the peace, when I see a shot fired it is up to me to nip it and keep the peace. Nuf said, back to the discussion, please.

Jim

Very low frequencies - say below 50 Hz - are not perceptually associated with “bass” or “thump” or “punch” but are much more like an indistinct rumble and the only type of content that uses very low frequencies regularly is films/movies. But there it’s not used for musical purposes but as a sound effect, e.g. explosions, starting rockets etc. So, imo there's no need of speaker bass directionality with very low freqs', the same couldn't apply in mid to upper low freqs where directionality imo and taste are a must.

I have no experience with sub woofers yet, I am hoping next year I will have a flat screen tv and decent surround sound system for movies, not sure if I will listen to the surround for music or keep the tunes on the 2 channel.

but I am a long way off.


elroy

I have no experience with sub woofers either, but i was a bass player for many years that's why i like low freqs so much and i know a little about them also.
For example, The sound of the bass does not only consist of the actual “fundamental” tone (i.e. 31 Hz in case of a deep low but also many multiples of that frequency (i.e. 62 Hz, 93 Hz, 123 Hz, etc.), which are called the “harmonics”. Thta's why i believe in the importance of directionality not only of the mid and upper bass freqs but most important, their harmonic struture.

EXACTLY! Two other factors that are often not considered are crossover slope and harmonic distortion of the subwoofer.

The subwoofer amp and/or driver and/or cabinet all contribute to the overall THD of the subwoofer. These distortions also occur at the same multiples (or "harmonics") that Clint e. describes, and are thus audible (more so in lesser quality systems) and directional.

Crossover slope also plays a significant role. A crossover doesn't provide a brick wall for all frequencies beyond its tuned frequency, rather it is a slope based on the design (or "order") of the crossover. For example... a 1st order low pass crossover would have a slope of 6db/octave. If tuned for 80Hz, frequencies at 160Hz would be reduced by only 6db, and 320Hz would be reduced 12db. These higher frequencies would still be very audible from the subwoofer and very easy to localize. Compounding the problem is the fact that most subwoofers are not designed to accurately output these higher frequencies, so THD can be even greater in this audible directional range. (think about those muddy sounding noise boxes in many home theater packages)

For these reasons most subwoofers use at least a 2nd order crossover (12db/octave), and many higher quality units use a multistage crossover that provides 12db/octave near the crossover point, and a combined 48db/octave starting an octave above the initial crossover point. This is a good compromise as the more gradular initial slope allows for a smoother integration of the subwoofer to the main speakers, while the steep secondary slope more completely supresses higher frequency more directional signals. In addition servo-control of the driver can be leveraged to increase accuracy of the output and reduce THD.

Rob

From the size of your sub cabinet you surely have a lot of low bass responce and a deeper cutoff....but there's some difference in your sub and the ones that use a bass reflex design. Yours are almost like transmission line woofers, which operates as direct radiators, therefore directionality is indeed a must.
Have fun.

I'll attribute my preference to forward-firing subs for what I consider the audible spectrum of upper-bass or lower midbass resulting in sound directionality.

I have heard down-firing subs that have been both elusive to find in a room as well as ones I was able to pick out.

The elusive models? Producing a low frequency range and placed properly in the room.

The ones I've been able to locate? Improperly placed (either by lack of effort or by need to fit into a "liveable" room) or producing enough upper range to become placeable.

I believe it's very possible for a well-placed down-firing sub producing the lower octaves to be able to dissappear but in my experience music-orientated subs that are asked to cover a larger range can be pointed out in a room if placement is not ideal or it's covering a large range.

I've therefore gravitated to a pair of front firing subs to work for me, who also needs to deal with placement issues.

Folks of whom I respect their opinions suggest I run three subs, and they also feel that down-firing subs can be used with great success if placed properly and with attention to detail.

But I need to include often they run subs that are lower-octave producers and venture little into upper bass/lower midbass territory.


In the end- whatever works for you is the best solution.

Okay- correct me if I'm wrong here or if you differ from opinion...

An electric bass and maybe an upright bass- the lowest notes they produce fall within 41-43Hz.

I'm able to pick out the bass in the room, especially if the upright, or single amplified- even if it's a full range player like Victor Wooten of Bela Fleck fame.

So- directionality at 41Hz can be discerned, I feel.



For musical range, I agree with you Alvarro- unless it's a heavy handed bass player, or some classical featuring tympani and pipe organ, there's the majority of the recording at loosely 50Hz and up.


But I'd still prefer a speaker that scrapes the 40Hz area, to wring out as much of the rock and roll as I can.

And if a speaker can go that low, maybe a down-firing sub with low cutoff could be integrated well.


But arguement has been made that bass becomes "non-directional" at numbers below 38HZ, others argueing at 35 or even 32-33Hz, and still others at around 26-28Hz.

So- running a full range speaker into the mid thirties or lower and a sub that cuts off at around 40hz or under could be "invisible", no?

Could this be the failure? Subs reproducing too high into the frequency range thus losing their transparency?

Where does bass directionality really become non-directional? Below 38Hz? Below 33Hz? 26Hz?



At a friend's house, he ran a sub for home theater with probably a 60Hz cutoff and it took me all of a minute to locate the sub, hidden behind a chair and using a wall as reinforcement.

Later with new speakers in the approximate 35Hz range or lower, give or take, and running "open", I'm guessing somewhere around a 35-40Hz cutoff for the sub, it became hard for me to pick out the sub- still in the same spot- setting my brain into high gear.


So where does bass become less reliant on directionality? For me, I'm thinking at least sub-35Hz, if not a bit more.

Or... Am I still just picking up on remnants of upper bass still?

By the way- sorry for getting a bit off topic.

dont forget that a piano can get just under 30hz and electronic tones even lower.

What's a big pipe organ bottom out at? 16Hz? 18? I know the biggies are in the teens....


And electronic D&B- what is the average? Augmented bass rattles dance floors and trunks of clapped out Civics, so what's it tuned to?

Bass notes have the longest wavelength in the audio spectrum, therefore room interaction have awesome impact in low and deeper low freqs in the way we listen (or not) and feel. As we all know, just because we can’t listen to some deeper low bass it doesn’t mean that we can’t feel them. We can.
Rooms imo are the most important factor concerning low and very low sound freqs. Rooms have gain. A small room, such as a bedroom, or if it is solidly built ie brick walls and concrete floor, then you may have quite a lot of gain.
Some frequencies begins showing itself at are determined by the room's dimensions. The commonly accepted belief is that below the lowest eigentone ( standing wave mode, and can be calculated by dividing 570.5 by the room's longest dimension, this will give you the half wavelength at that freq ) of the room, the room can exhibit a rise in SPL of up to 12db per octave as you go down in frequency.
But, in reallity, listening rooms are fairly lossy, and room gain begins well above most rooms lowest eigentone. An average room could look like plus 1-2db at 70-80hz, plus 6db at 40-45hz, and plus 9db at 20hz. Now if we add to this a sub bad crossover design, a sub in a poor room position or no room treatment, surely we have bass rolloff through all the freqs range…That’s one of the reasons ( beside a few others, like WAF) i give up my project of a “concrete sub woofer” I’d started a few years (remember?) because I’d found out that I haven’t the good/right room for placing such a big bass reflex kind of woofer…

are you calling clint a heavy handed bass player? wow, thems fighting words, btw I am glad this turned out to be a great thread

elroy

I was fast and heavy too, but no way a heavy handed bass player. I have a great bass rig in those days. I had - still have - a Trace Elliot amp with two cabinets. One with two 10" Celestion speaker drivers and a Celestion horn driver, for bass upper harmonics and the other cabinet with a 15" Celestion driver for deep bass responce. Apart that i had also a beautiful 100 watt valve amp head from Marshall, the JCM 800 together with a Marshall cabinet with four 12" Celestion drivers. I used to have a an active crossover from Bheringer where i'd split the deep low freqs from the upper lows. I'd send the the lower ones to the Trace amp and uppers to a Boss distortion pedal and an Electro-Hamonix Big Muff and than to the Marshall amp. Yeah! my bass sound was like a monster......, something similar to Doug Pinnick of Kings X played in the "Dogman" album.
Tanx for memories.