Design differences between Accugrooves

Different speakers, crossover components, crossover points, and cabinet structures.

Are you really asking about what the tonal differences are? If so, your question would be best answered by trying out both cabs with similar equipment.

 

I had a discussion about the Bill Dicken's vs. Whappo Jr. with Glenn at Austin Bass Traders a while back when I was considering a new cab. I ended up not going with Accugroove for a number of reasons at the time, but from my memory of the discussion, the Bill Dicken's cab has two non-Neo 12" woofers, a larger midrange driver and the same soft-dome tweeters as the Jr. The Jr. has a 12" neo woofer, a 12" neo lower mid driver, a smaller upper mid speaker and the two soft domes. So, the Dicken's cab is more of a '3 way' vs. '4 way' sort of thing. From the sound description the Glenn gave me, the Dicken's is a little more scooped with more aggressive upper mids (and a lot heavier and more expensive!).

I don't have direct experience, and I know the Accugroove guys have been changing the designs of the cabs (this info is based on the discussion I had with Glenn about a year ago). Since I haven't seen many posts on the Dicken's cab, I thought I'd post my limited info.

 

do they have a switch?

 

They all seem to be designed with the same disregard for speaker engineering principles.....

I'm told they sound good, but I'd be interested in seeing response plots to see if they're as flat as everyone seems to think they are. I'd guess not, but then again, flat doesn't necessarily equate to good sound. The complete lack of any useful tech information on their site annoys me.

 

Mark, just for the record, most of us call them flat, but what we really mean is that they are flatter, meaning flatter than other available cabinets, and more like the sound of studio monitors or high-end sound reinforcement. Having some response plot on their website is meaningless unless we can superimpose them over similarly obtained plots of competing speakers tested under similar conditions.

It's my understanding the Dickens cabs are not intended to have that same flatness to them.

 

Are they? They certainly have better bass extension than most bass cabs but I can make an educated guess that the midrange and top end are anything but flat. What I wonder is whether people equate good bass extension to flat response. Again, flat isn't necessarily desireable either....

I'd like to see detailed amplitude and phase response plots for every speaker, not just Accugroove. However, that would only have a certain amount of bearing on any decisions. As useful as specs and measurements are, I still rely on my ears for final decisions.

 

Mark,

Have you ever given an Accugroove Cab a serious go or do you just rely on other peoples views? I say this because I looked at your profile and saw what cabs you use.

Just curious

Matthew

 

Nope, but I'd like to do that. However, I do know what 'flat' cabinets sound and measure like and I could tell you in a second whether a cab is close or not.
My guess that the Accugroove cabs are not 'flat' in the mid and high frequency ranges is based on my observations on how the cabs are designed, not on anyone's views. Note, I'm not saying that flat necessarily equals good.

 

Mark, here's my experience which I've believed I've shared before. I went into Sheffield Recording here in Maryland last year for a project recording demos. I went direct into the board, and was miked as well with the purpose of being able to choose the better sound for a particular song or to blend the two. After doing a couple songs, the chief engineer asked me to come into the control room because he felt he was wasting time. My tone through my Aguilar 750 into my Whappo Jr. was indistinguishable from my direct sound. This was in the opinion of the chief engineer of the studio, the producer, and myself.

Within a month of that, I was in a different studio recording a CD. Same setup, miked and direct. During the first song, the engineer came out, started moving the mics away from my cabinet and turning my amp off. I asked him what the heck he was doing? He said there was no difference between the two tracks.

What's your experience with an Accugroove?

 

I'll probably ruffle a few feathers posting this but I've been having some correspondence with someone very well versed in speaker design who bought a AccuGroove cab for testing. His views:

"Incorrect cab tuning. Even if the thing rolls off, it needs to be in phase with itself down low, or you can't even EQ it. Junk.

He uses a single-section crossover (cap only) to roll off both the mid and tweet. These are the only two reactive components in the entire crossover, other than the irrelevant Accuswitch.

There is nothing wrong with this. When you can get away with this, use it. BUT, for attenuators, he uses simple rheostats, not impedance-correcting L-pads... Simple rheostats increase apparent driver impedance as attenuation increases. As the apparent driver impedance INCREASES, the crossover frequency DECREASES. So the system changes in sound when the attenuators are used, and the midrange and tweeter are subjected to lower frequencies than intended.

The impedance curves you showed me will change as the attenuators are introduced.

The screen made a horrendous rattle. The ports themselves were noisy due to hard right-angle boundaries and the fact that they "fired" through the front screen. The cabinet itself was resonant and noisy.

Sine waves were so noisy and distorted that the cab sounded blown."

And regarding the impedance plots that Petebass got from the El Whappo:

"BTW, the impedance curve indicates a cab tuning frequency of 40 Hz. Below this frequency, the system will roll off at a rate of 24 dB per octave. I'll leave it to you to calculate how much it will be down at 30.87=B. It will be a lot. This is a measurement I had intended to make, but my computer crashed that night..."

I have my own theories on why so many bassists are enjoying the AccuGroove cabs - and good for you if you are! But I'm pretty convinced that flat 'audiophile' response is not the reason.

Alex

 

I'm with Mark on this one.... from my experience with the Ag750, that amp has a very, very, very distinctive voice... about as colored as you can get. So... the Accugroove somehow eliminated the impact of the 750 and made your bass sound exactly like it did through the board direct If that's the case... dump that lead sled and get an AI Clarus

I've also had very good luck with my Epi's, my EA's, and my BagEnds back in the day getting a very similar sound versus direct into a board.... it's mostly in the hands and experience with subtle EQ IMO.

Edit: Sure not slamming Accugroove... not my sound, but I understand why people like them.... but this 'flat' thing (especially the example above) still is silly to me.

 

I hear exactly what you're saying KJung, but that's my experience, so I thought I'd relate it. BTW, did you know I actually do have a Clarus (I assume you saw that). And, yes I do run the Clarus through my 'grooves as well.

I think your comments on being light on the EQ and knowing how playing style affects tone is dead on. Hand placement, etc., all definitely play their roles.

I have no doubt that Epis are relatively flat as well, that's my (limited) experience, and what I've heard.

Not sure why the flat thing is silly, though. It seems only logical that some cabinets would be more colored than others. Different designers are going for different flavors in the tone. What am I missing about what's peeving you? In your experience with Accugrooves, do you feel that they are more colored than other cabinets?

 

+1 Not peeved at all at your post , just love the discussion, etc. with other people as passionate about their tone as I am Also, statiing the 'flat thing is silly' was a little too strongly worded bases on what I was trying to point out I've found this sort of dialectic between other TBers very helpful in putting a context around what gear I would be interested in, and also explaining some of the things I hear when I 'audition' a piece of gear.

 

Don't worry, I know where you're coming from, I value your experience as well--heck I suspect we both have been playing for over 30 years. I value your opinion. I was seriously curious about your take. I know from another thread that you had a chance to audition Accugrooves, but I forget which models. Where would you place them on the flatness spectrum? Say, not as flat as Epis, but more so than Bergs?

BTW, I also totally agree with your and Mark's point, which simply stated, is, "Who cares if it's flat, the question is whether it's good." I'm with you on that, but once you have quality sound, then some of us do value relative flatness, for the tonal flexibility it gives. I go from jazz to classic rock to modern rock, so flexibility is very valuable to me.

And btw, millner should probably PM BigString, because I know he auditioned the Bill Dickens cabs on at least one occasion.

 

30 years is about right! Kind of scary!!!! I'm actually one of those guys who agree with the Bass Player review of the somewhat polite treble response of the Accugrooves... especially the Whappo, with that huge low end. I felt the same way about my old EA VL's and my Acme's. When I played the Whappo, the Jr. and the 210 (granted all in a music store setting, which we all know is not the real world of what gear really sounds like), they all sounded different enough that it again reinforced my confusion about 'flat'.

As far as being flexible, I found that I could easily dial out the treble response in other cabs like the Epi, but could not 'add' that sort of sizzle into these 'soft dome' type tweeter cabs, actually making them less flexible for me. However, many players don't go for the sort of sound that I go for, so this issue is probably a moot point for most. My guess is, most basses don't even have the kind of frequency response to even notice this, which might be where all the violent disagreement with the BP review came from. Who knows, though!

I hope you Accugroove guys notice that I also recommend these cabs to TBers who are going for a warmer, more classic fingerstyle tone... I love my Epi's and Schroeder's, but totally realize that sound is not for everyone. If I was a PBass guy, or was really going for the 'Fodera NY sort of Anthony Jackson vibe... I would jump on one of these cabs in a minute! I even recommend the Berg NV's to 'tube rockers', and those cabs are about as far away from what I like as they can be. However, I guess I always push back a little when these 'flat' type cabs are marketed as being able to give you any sound you want... that's simply not the case IMO... they sound like they sound... if you like it great and they fit the 'sound in your head'... awesome!

 

Add to this the fact the there are only high pass filters on the mid and tweets, which means the woofers get a full range signal. So what, right? Most woofers have strong output up to 2kHz or beyond, so the woofer and mid will be producing a lot of the same information. That's good, right? Mutual coupling and all that. Nope. Once you get above the frequency whose half-wavelength is shorter than the distance between the driver centers, you're going to get comb filtering and lots of it. If you look at the way the Whappo Jr. is set up you'll see not one but two paths between the woofers and the mid. If both woofers are just high passed, both will cause their own comb filters with the mid.
The other immediately obvious issue is the double tweeter, for the same reasons. Look through a few Stereophile magazines and see how many cabs have two tweeters. None. Why? Because it's not a very smart idea. With two soft dome tweeters, you can't get the driver centers close enough to not comb filter at some frequency. in this case the tweeters look to be about 8-10cm center to center. So everything above about 2kHz is going to be subject to comb filtering. That's going to make the on-axis frequency response messy as hell.

 

I don't have any personal experience with Accugroove and I've never claimed that they don't sound good, I'm sure they do. I'm questioning the veracity of their 'accurate' claims based on actual physics. Simply, that there isn't any possibility of the cabs being flat based on their design criteria.

I probably would have never paid any attention to it save for the whole Accuswitch thing.