when is bass "big"?

A 10" driver in a 1 ft3 enclousure with an 18hz F3 !!!! does the sub have 5" of excursion and 4000 watt power handeling or am I missing something? lol

You HAVE to tell me which sub your talking about!

The O

 

**Jumps up and down, waving his hand...**

Is it the Velodyne DD-10?

Dunc

 

well,the bass drivers are 4" on the Sparks,but they do more than enough for me.

 

Blue Peter badge for that man.

Yes it's the Velodyne DD10 – mega watts (1250rms), a pretty special driver (don't know the excursion I'm afraid) and servo control to keep it all clean. Quite an amazing little beast – I think it's around £2K though so that kind of engineering doesn't come cheap.

The specs are here: http://www.velodyne.com/velodyne/products/specs/DigitalDrive.html

They also do a 12â€Â, 15†and 18†version, each getting gradually deeper (17, 15 and 14Hz respectively).

Matt.

 

Velodyne are the cream of sub design after all ;-) Yes, amazing, the servo control is the key to keeping it all together, but still a small box with high excursion needs serious power and extreme driver design hence the price, but worth considering paying if space is a premium.
I wonder what the group delay figures are like for these subs?

The O

 

The Oracle - I've a feeling I've seen you on another forum before...and that your interest in Velodyne is not entirely a personal one

Michael.

 

Impulse response would be more interesting given the enormous mass they have to accelerate. I've heard most of the big Velodynes. great for movies - look elsewhere for music IMO.

 

Surely impulse is a high frequency phenomenon (hence the need for super tweeters). Subwoofers only flap around in the low tens of Hz. Surely they don't need an amazing impulse response. More important is that their flapping is in phase with the higher frequency components of the sound.

 

Not for me Chris, I'm not a fan of relying on your main speakers to perform bass duties above 50hz or so. Just my preference.

Big bass driver running up to 200hz = grin

 

I just thought I would say if you want deep bass PMC are defiantly the best I have heard. I have been using a pair of active BB5's at a studio quite a bit and the bass is amazing!

If the MB1's are anything like the BB5's you won't need to look any further

Another exception to the rule is my PMC AML1's. They go to 25hz in my room and they only have a 5" driver! Perfectly clean, no distortion and very very fast. Not to mention the rest..

Thumbs up for PMC

 

What's the output at 25hz? Max spl about 70db?

I think this is the problem, small drive units do not produce "big bass" They simply cannot move enough air to produce decent spl's at low frequencies.

 

Speaking from experience (big Velodyne HGS15), I found that it's performance with music was nigh on perfect as one might expect from a subwoofer with virtually nil distortion. At the time I did some A/B comparisons by playing stereo music through a pair of KEF Ref 2-2's on their own and then switching in the sub using an 80Hz crossover (this was done by switching between 'direct' and direct+sub' on my Tag). Of course the bass was deeper when the sub was playing but, crucially, it also sounded cleaner/faster. The other benefit (not really relevant to this debate mind you) was that the higher frequencies sounded better too with the sub playing - I guess this was mainly down to the fact that the amp and the speakers could apply all their power to the 80Hz plus stuff.

One this I genuinely don't understand is the talk of transient response (or impulse response) shortcomings in these big servo subs. To my (non technical) mind, if a sub has little or no distortion then it must be accurately reproducing the input signal it receives – and if it is reproducing the input signal perfectly then how can there be any response shortcomings? Surely if the driver is unable to respond to the demanding transients of the music then it would NOT be reproducing the input signal accurately and would therefore have higher distortion figures. Maybe I have misunderstood the whole issue.

Merlin – over to you to explain....

Matt.

 

I too get less bass overhang and cleaner transients by crossing over at 120hz. As you say, imaging and treble sweetness improves too. This is probably due to the reduction in intermodulation distortion as much as anything, a very real benefit of biamping.

The initial impulse response of the big velodyne unit is noticeably more gradual than ideal, although it could be argued that the rise time of a deep bass note makes this irrelevent. My listening experience would suggest otherwise. Imagine a bass note, it's fundementals produced by the DD15 whilst it's harmonics are the product of the midrange driver in your main speakers.

The initial impulse responses of both units should be the same in order for the note to be portrayed accurately. The extra time taken by the Velodyne to get up to speed will give the impression of the subs being located behind the main speakers. This will give added warmth and body, at the expense of an increase in group delay, which will slightly soften transients.

In practice these effects are subtle, and indeed you may prefer a little delay. I just prefer other approaches.

 

They simply cannot move enough air to produce decent spl's at low frequencies.

i accept that,my drivers are only 4" on the Sparks,but i listen mostly to guitar/vocals,so what am i missing? (I dont have any Barry White ).

I cant understand why a manufacturer would make a £1750 pair of speakers and only make the river 4" if it coulsnt replicate bass properly

 

£1750 is pretty cheap for speakers that can't do bass. Naim charge far more than that.

 

Hurrah hurrah! Happy days. My sub has returned and normal service has been resumed

I'm afraid I don't buy that explanation at all. Particularly since my amp and main speakers are doing exactly the same thing whether the sub is on or off and the difference is very very obvious when the sub is on. I have really missed my sub during the last two weeks. I believe there is information on the disc right down to 20 Hz and below. It may not be much. It might sound like gentle murmurings. But it sure as hell makes a big difference to the whole sound of the system, as you noticed.

Can't say I've noticed any softening of transients with the sub on. However, Mr. Thwack himself is coming over on Friday so we'll get a second opinion on that

 

I'm not sure what the Max SPL is. Where would I find that out?

They certainly do not bottom out when playing loud.. they have A LOT of power. I have the power amps set to about 10 o'clock and the pre-amp still never needs to go much over 12 o'clock to achieve permanent hearing loss levels. I do have a small room though.

They do 25hz at -3db.

 

excellent news,i will sleep better now

 

Aha but hang on a minute Mr Bear - unlike in your set up where the sub is connected at speaker level, I was using a Tag AV processor that was actually 'bass managing' the system (the sub being connected via a line level input).

Therefore, when I selected 'direct+sub', the Tag sent only signals above 80Hz to the mains with everything below this going to the sub (obviously with the given roll off slopes etc) - so, in this situation, the main speakers and amp driving them all of a sudden were relieved of their <80Hz duties. In the 'direct' mode (that I was using as the comparison) the mains received the full signal and the sub got nothing.

I agree with you that there are other reasons why adding a sub can make the mids and highs sound better but logic says to me that there may well be some sonic benefit when the main speakers and amp no longer have to worry about producing the 35Hz-80Hz part of the frequency spectrum.

Anyway, good to hear you've got your sub back anyway.

Matt.

 

:lol:

Yes, I see what you mean and given my own experience of bi-amping with the Arcams, I am sure you are right.

But adding in those missing Hz (from 20 to 35 in my case) really does make quite a difference even when the amp is working no less hard. Mind you, the ATC is one ballsy amp so working hard actually equates to 'insanely loud' here at Technobear Towers

Just for interest, the in-room measurements with my REL Storm III are flat to 22 Hz and about -3dB at 19 Hz